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Braz. j. biol ; 84: e252364, 2024. graf
Article in English | LILACS, VETINDEX | ID: biblio-1355885


Abstract Understanding morphological and physiological changes under different light conditions in native fruit species in juveniles' stage is important, as it indicate the appropriate environment to achieve vigorous saplings. We aimed to verify growth and morphophysiological changes under shade gradient in feijoa (Acca sellowiana (O. Berg) Burret) to achieve good quality saplings adequate to improve cultivation in orchards. The saplings were grown for twenty-one-month under four shading treatments (0%, 30%, 50%, and 80%). Growth, photosynthetic pigments, gas exchanges, chlorophyll fluorescence, and leaf anatomy parameters were evaluated. Saplings under full sun and 30% shade had higher height and diameter growth and dry mass accumulation due to higher photosynthesis rate. As main acclimatization mechanisms in feijoa saplings under 80% shade were developed larger leaf area, reduced leaf blade thickness, and enhanced quantum yield of photosystem II. Even so, the net CO2 assimilation and the electron transport rate was lower and, consequently, there was a restriction on the growth and dry mass in saplings under deep shade. Therefore, to obtain higher quality feijoa saplings, we recommend that it be carried out in full sun or up to 30% shade, to maximize the sapling vigor in nurseries and, later, this light environment can also be used in orchards for favor growth and fruit production.

Resumo A verificação de mudanças morfológicas e fisiológicas sob diferentes condições luminosas em espécies frutíferas nativas em estágio juvenil é importante, uma vez que indicam o ambiente adequado para a formação de mudas com alto vigor. Objetivou-se verificar o crescimento e as alterações morfofisiológicas sob gradiente de sombreamento em mudas de feijoa (Acca sellowiana (O. Berg) Burret) para obter mudas de boa qualidade, adequadas para fomentar os plantios da espécie em pomares. As mudas foram cultivadas por vinte e um meses sob quatro tratamentos de sombreamento (0%, 30%, 50% e 80%). Foram avaliados parâmetros de crescimento, pigmentos fotossintéticos, trocas gasosas, fluorescência da clorofila e anatomia foliar. Mudas a pleno sol e 30% de sombra apresentaram maior crescimento em altura, diâmetro e acúmulo de massa seca, devido à maior taxa de fotossíntese. Como principais mecanismos de aclimatação sob 80% de sombra, as mudas desenvolveram maior área foliar, redução da espessura do limbo foliar e aumento do rendimento quântico do fotossistema II. Mesmo assim, a assimilação líquida de CO2 e a taxa de transporte de elétrons foram menores e, consequentemente, houve restrição ao crescimento e acúmulo de massa seca das mudas no maior nível de sombreamento. Portanto, para a obtenção de mudas de feijoa de maior qualidade, recomendamos que seja realizada a pleno sol ou até 30% de sombra, para maximizar o vigor das mudas em viveiros e, posteriormente, este ambiente de luz também pode ser utilizado em pomares para favorecer o crescimento e a produção de frutos.

Myrtaceae , Feijoa , Photosynthesis , Plant Leaves , Acclimatization , Light
Article in Chinese | WPRIM | ID: wpr-942335


Objective : To study the effect of temperature and light intensity on photosynthetic fluorescence parameters, volatile oil content, and growth of Atractylodes lancea and provide reference for the rational selection of cultivation environment for A. lancea. MethodWe determined the photosynthetic indexes (such as net photosynthetic rate, water use efficiency, and carboxylation rate), light response curve, CO2 response curve, fluorescence parameters, and the content of four volatile oils in A. lancea under two temperature treatments (32 °C and 22 °C) and two light treatments (full light and shade). ResultThe net photosynthetic rate and water use efficiency of A. lancea under high temperature + strong light were significantly higher than those under high temperature + weak light and low temperature + strong light. The ability of A. lancea to use weak light at low temperature was the strongest, while the utilization rate of weak light under strong light significantly reduced. The photosynthetic rate of A. lancea at low temperature was more susceptible to light intensity and CO2 concentration than that at high temperature. The maximum photosynthetic rate and apparent quantum efficiency under weak light were significantly higher than those under strong light. The photoreaction efficiency at high temperature was higher than that at low temperature. The total amount of volatile oil in A. lancea treated with high temperature + weak light was the highest, reaching 4.582%. Compared with high temperature + strong light, high temperature + weak light significantly increased the content of hinesol and β-eudesmol in A. lancea by 91.7% and 35.7%, respectively, and low temperature + strong light significantly increased the content of hinesol by 87.5%. The content of β-eudesmol in low temperature + weak light treatment was significantly lower than that in high temperature + weak light treatment. ConclusionTThe growth of A. lancea was affected by the interaction between temperature and light. The light and temperature conditions required for the accumulation of volatile oil were not consistent with those suitable for the growth and development of A. lancea. A. lancea responded to the changes of light and temperature conditions by regulating the synthesis and accumulation of volatile oil.

Article in Chinese | WPRIM | ID: wpr-940774


ObjectiveTo study the effect of organophosphate-solubilizing bacteria and compound bacteria on the photosynthesis and physiological and biochemical characteristics of leaves of Paris polyphylla var. yunnanensis, and to provide a reference for selecting suitable bacterial fertilizers in artificial cultivation of this medicinal species. MethodPot experiment was carried out indoor and the following groups were designed: control (CK), inoculation with Bacillus mycoides (S1), inoculation with B. wiedmannii (S2), inoculation with B. proteolyticus (S3), inoculation with B. mycoides and B. wiedmannii (S4), inoculation with B. mycoides and B. proteolyticus (S5), inoculation with B. wiedmannii and B. proteolyticus (S6), and inoculation with B. mycoides, B. wiedmannii and B. proteolyticus (S7). Then, the growth and development, photosynthesis, and various physiological and biochemical indexes of the leaves of this species were observed. ResultCompared with CK, the treatment groups showed decrease in content of malondialdehyde in the leaves (P<0.05), particularly S7 (content was only about 1/3 that of the CK). The leaf area, photosynthetic parameters, photosynthetic pigment content, soluble sugar content, soluble protein content, and activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in leaves of the treatment groups were all improved. Among them, the leaf area, soluble sugar content, and soluble protein content were the highest in S7, which were 2.8, 2.1, and 2.2 times that of the CK, respectively. SOD activity peaked in S6 (2.9 times higher than that in the CK) and the highest activity of POD and CAT was detected in S5 (1.5 times and 2.1 times, respectively higher than that in the CK). ConclusionInoculation with different organophosphate-solubilizing bacteria or compound bacteria can promote the growth and development of P. polyphylla var. yunnanensis and improve its resistance to stresses. The combination of B. mycoides and B. proteolyticus and the combination of the three achieved the have the best effect. This study provides a reference for the selection of bacterial fertilizers for artificial cultivation of P. polyphylla var. yunnanensis.

Article in Chinese | WPRIM | ID: wpr-940396


ObjectiveTo study the effects of foliar spraying of two kinds of compound rhizosphere growth-promoting agents on the growth and physiological characteristics of Angelicae Sinensis Radix (ASR), as well as the pharmacodynamic components, in order to lay a foundation for providing functional microbial agents for ecological cultivation of ASR. MethodThe compound growth-promoting agents T1 (Pseudomonas CBS5, CBS7 and CBSB) and T2 (Bacillus 5C1, 5C5 and 5C7) with the concentration of 1×108 CFU·mL-1 were sprayed on the leaf surface of the field, and the sterile potato glucose broth medium was used as the control (CK). The plant growth indexes of ASR were measured by conventional methods, the photosynthetic physiological indexes of ASR were measured by portable photosynthetic measurement system, the enzyme activities of plants and microorganisms were measured by kit method, and the endogenous hormone levels were analyzed by ultra-performance liquid chromatography tandem mass spectrometry. The contents of ferulic acid, senkyunolide I, coniferyl ferulate, senkyunolide A and Z-ligustilide were determined by high performance liquid chromatography. ResultCompared with CK, the two compound inoculants could promote the growth of ASR and increase the biomass, increase the leaf net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, increase catalase, peroxidase, superoxide dismutase, polyamine oxidase, diamine oxidase and polyphenol oxidase enzyme activities, increase endogenous jasmonic acid, cytokinin and gibberellin levels in plants, increase the contents of ferulic acid, senkyunolide A and Z-ligustilide, reduce the contents of malondialdehyde and abscisic acid, and reduce the incidence of root rot. ConclusionFoliar spraying of two kinds of rhizosphere compound growth-promoting agents can promote the growth, photosynthesis and stress resistance of ASR, and can improve the quality of ASR in different degrees. Comprehensive analysis shows that T1 treatment is better than T2 treatment in the growth-promoting and quality-enhancing of ASR.

Ciênc. rural (Online) ; 52(10): e20210282, 2022. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1375115


Photoassimilate partition and allocation among plant organs varies throughout their development and is also influenced by factors inherent to the genotype and the environment. Nodulation in the soybean-diazotrophic bacteria interaction is more effective than in the bean-diazotrophic bacteria interaction. This investigation studied growth and photoassimilate partitioning throughout the bean and soybean cycles and inferred how much it could affect the nodulation of the roots. For this purpose, an experiment with two treatments was carried out, soybean (cultivar BRS GO - 7760 - RR) and bean (cultivar BRS Estilo), with four replications, conducted in pots and entirely randomized. The seeds were inoculated with commercial rhizobia specific for bean and soybean LeguMax® (Novozymes-Turfal). Plants were analyzed throughout their cycles based on leaf area and dry mass of all organs, including nodules. Mathematical models were fitted to the data and based on them, the instantaneous physiological indicators of growth were estimated, and the percentages of photoassimilate partition among organs were evaluated. Crop growth rate, relative growth rates, net assimilation rate as well as net photosynthesis rate had higher values in soybean compared to bean, following the pattern of leaf area and total dry mass. For both species, the highest rates occurred at the beginning of the cycle, decreasing with age. Unlike the bean, soybean has a high capacity to supply photosynthates to all of its organs throughout its entire cycle, favoring the maintenance of nodule growth and explaining its greater capacity for nitrogen assimilation.

Durante o desenvolvimento das plantas a partição e alocação de fotoassimilados variam entre os seus órgãos, e dependem de fatores inerentes ao genótipo e ao meio ambiente. A nodulação é mais efetiva na interação soja-bactéria diazotrófica do que na interação feijão-bactéria diazotrófica. Esta pesquisa tem como objetivo estudar o crescimento e a partição de fotoassimilados ao longo dos ciclos do feijão e da soja e inferir o quanto isso pode afetar a nodulação das raízes. Para tanto, foi instalado um experimento com dois tratamentos, soja (cultivar BRS GO - 7760 - RR) e feijão comum (cultivar BRS Estilo), com quatro repetições, conduzido em vasos e inteiramente ao acaso. As sementes foram inoculadas com inoculantes comerciais específicos para feijão e soja LeguMax® (Novozymes-Turfal). Plantas foram coletadas ao longo de seus ciclos e medidas as áreas foliares e as massas secas de todos os órgãos, incluindo nódulos. Modelos matemáticos foram ajustados aos dados e, com base neles, foram estimados os indicadores fisiológicos instantâneos do crescimento e, também, foram avaliadas as porcentagens de partição de fotoassimilados entre os órgãos. A taxa de crescimento das culturas (CGR), as taxas de crescimento relativo (RGR), a taxa líquida de assimilação (NAR) e a taxa líquida de fotossíntese (Pn) apresentaram maiores valores na soja em relação ao feijoeiro. Para ambas as culturas as maiores taxas ocorreram no início do ciclo, decrescendo ao longo do ciclo cultural. Diferentemente do feijoeiro a soja tem alta capacidade de suprir de fotoassimilados a todos os seus órgãos ao longo de todo o seu ciclo, o que favorece o maior crescimento dos seus nódulos, justificando a sua maior capacidade na captura do N2 atmosférico.

Photosynthesis , Soybeans/growth & development , Biomass , Phaseolus/growth & development , Root Nodules, Plant
Chinese Journal of Biotechnology ; (12): 592-604, 2022.
Article in Chinese | WPRIM | ID: wpr-927730


Cyanobacteria are important photosynthetic autotrophic microorganisms and are considered as one of the most promising microbial chassises for photosynthetic cell factories. Glycogen is the most important natural carbon sink of cyanobacteria, playing important roles in regulating its intracellular carbon distributions. In order to optimize the performances of cyanobacterial photosynthetic cell factories and drive more photosynthetic carbon flow toward the synthesis of desired metabolites, many strategies and approaches have been developed to manipulate the glycogen metabolism in cyanobacteria. However, the disturbances on glycogen metabolism usually cause complex effects on the physiology and metabolism of cyanobacterial cells. Moreover, the effects on synthesis efficiencies of different photosynthetic cell factories usually differ. In this manuscript, we summarized the recent progress on engineering cyanobacterial glycogen metabolism, analyzed and compared the physiological and metabolism effects caused by engineering glycogen metabolism in different cyanobacteria species, and prospected the future trends of this strategy on optimizing cyanobacterial photosynthetic cell factories.

Carbon/metabolism , Carbon Dioxide/metabolism , Cyanobacteria/metabolism , Glycogen/metabolism , Metabolic Engineering , Photosynthesis/physiology
Braz. arch. biol. technol ; 65: e22210338, 2022. tab
Article in English | LILACS-Express | LILACS | ID: biblio-1364474


Abstract: Climatic variation throughout the day influences the ecophysiological performance of plants at different growth stages and phases. Therefore, this work aimed to evaluate the effect of climatic variation on ecophysiological aspects of T. roseoalba and H. heptaphyllus at different hours of the day and indicate the ideal time for measuring ecophysiological variables in these species. The research was carried out in a greenhouse at the forest nursery of the Federal University of Paraíba, Campus II, in the municipality of Areia, Paraíba state, Northeastern Brazil. The experimental design was completely randomized, consisting of 10 evaluation times throughout the day (from 8 am to 5 pm), with 1 h hour interval between each evaluation. Temperature and air relative humidity inside and outside the greenhouse were evaluated to understand the effect on gas exchange (net assimilation rate of CO2, stomatal conductance, transpiration rate, internal concentration of CO2, and vapor-pressure deficit) and chlorophyll a fluorescence (initial, maximum, and variable fluorescence, photochemical quenching, and electron transport rate). Data were submitted to canonical correlation analysis and principal component analysis to verify the relationship between climatic and ecophysiological variables. For both species, higher correlation was found between internal and external relative humidity with all the ecophysiological variables analyzed, except for initial fluorescence. Thus, climatic factors influenced the photosynthetic performance of T. roseoalba and H. heptaphyllus plants, and 8 am to 9 am is indicated for carrying out ecophysiological evaluations in both species.

Acta biol. colomb ; 26(1): 12-18, ene.-abr. 2021. tab, graf
Article in English | LILACS-Express | LILACS | ID: biblio-1152664


ABSTRACT Leaf anatomy characteristics provide important evidences about the transition between C3 and C4 pathways. The C4 photosynthesis pathway allowed to reduce the C3 photorespiratory rate, concentrating CO2 around the Rubisco site and using structures and machinery already presented in C3 plants. In monocots, it is observed a high number of C4 lineages, most of them phylogenetically related to C3 groups. The genus Apochloa (C3), subtribe Arthropogoninae, is related to two C4 genera Coleataenia and Cyphonanthus. The aim of this study was to evaluate four Apochloa species in order to establish anatomical characteristics related to the evolution of C4 pathway in this group. By means of transverse sections fully expanded leaves of A. euprepes, A. lorea, A. molinioides, and A. poliophylla were collected and the characteristics of the mesophyll (M) and bundle sheath (BS) cells were determined. These species showed a rustic Kranz anatomy with enlarged and radial arranged BS cells, which have few organelles organized in a centrifugal position. Although the modifications of BS cells are probably related to the maintenance of plant water status, we also discuss the evolution for the establishment of C4 photosynthesis in the related C4 genera.

RESUMEN Las características de la anatomía de la hoja proporcionan evidencias importantes sobre la transición entre las vías C3 y C4. La fotosíntesis C4 surgió para reducir la tasa de fotorrespiración C3, concentrando el CO2 alrededor del sitio de la Rubisco y utilizando estructuras y maquinaria ya presentes en las plantas C3. En monocotiledóneas, se observa un alto número de linajes C4, la mayoría de ellas filogenéticamente relacionadas con grupos C3. El género C3 Apochloa, que pertenece a la subtribu Arthropogoninae, está relacionado con dos géneros C4 Coleataenia and Cyphonanthus. En este contexto, el objetivo fue evaluar cuatro especies de Apochloa para establecer las características anatómicas relacionadas con la evolución de la via C4 en este grupo. Se colectaron hojas completamente expandidas de A. euprepes, A. lorea, A. molinioides y A. poliophylla y se determinaron las características de las células del mesófilo (M) y del haz de la vaina (HV) a partir de secciones transversales de la hoja. Las especies presentaron una anatomía rústica de Kranz con células HV agrandadas y de distribución radial, con pocas organelas organizadas en posición centrífuga. Aunque las modificaciones de las células HV están probablemente relacionadas con el mantenimiento del estado hídrico de la planta, se puede inferir que facilitan el establecimiento de la fotosíntesis en los géneros C4 relacionados.

Article in Chinese | WPRIM | ID: wpr-906090


Objective:To investigate the physiological response of Ginseng Radix et Rhizoma with different phenotypes to high light stress under farmland cultivation mode, and to provide theoretical support for breeding of and fine management of new varieties of farmland ginseng. Method:Four-year-old ginseng plants with different stem colors were used as materials, and blue film was replaced by the colorless and translucent film for performing high light stress and investigating the change of growth status, light response curve, photosynthetic and fluorescence parameters of ginseng leaves. Meanwhile, the physiological adaptability and cell ultrastructural differences of ginseng with different phenotypes for strong light were compared by analyzing the variation of leaf ultrastructural characteristics before and after the stress. Result:The color of ginseng leaves became weak and the content of chlorophyll was greatly decreased with burning phenomenon on the leaf margin under high light stress. The maximum net photosynthetic rate and light saturation point of purple-stem ginseng were higher than those of green-stem ginseng. Transpiration rate, water use efficiency and other gas exchange parameters of purple-stem ginseng had adversity advantages, photosynthetic electron transport rate, maximum photochemical efficiency, photochemical quenching coefficient and other chlorophyll fluorescence parameters were higher than those of green-stem ginseng. There were changes in ultrastructure of the two germplasms, and the plasmolysis of green-stem ginseng was more obvious, its chloroplast membrane ruptured, the contents were exuded and the accumulation of starch grains and osmiophilic bodies increased. The chloroplast membrane structure of purple-stem germplasm was relatively stable, and its number of multivesicular bodies increased significantly by comparing with that of green-stem ginseng under high light. Conclusion:High light stress inhibits the leaf growth of farmland ginseng with different stem colors. The photosynthetic efficiency of green-stem ginseng is obviously reduced, and the integrity of chloroplast is damaged, leading to the weak physiological resistance. The purple-stem ginseng can reduce the damage of the photosynthetic system of plants under high light stress by its special cell structure and non-photochemical quenching advantages. Therefore, the purple-stem ginseng can be cultivated into a new resistant variety.

Article in Chinese | WPRIM | ID: wpr-905080


Objective:To study the effects of different drought conditions on the growth and photosynthetic physiological parameters of Acanthopanax senticosus,in order to provide the theoretical basis for standardized planting and rational development and utilization of A. senticosus. Method:In this study,three-year-old A. senticosus was used as experimental samples. The growth parameters,photosynthetic parameters,and photosynthetic physiological parameters were determined to study the effects of different drought conditions on the growth and photosynthesis of A. senticosus. Result:The plant height and leaf number were significantly lower than the control group under drought stress conditions,and the leaf area was higher than the control group under drought stress. Net photosynthetic rate,stomata conductance and transpiration rate were not significantly different between the control group and the moderate drought stress group. They were significantly decreased in the severe drought stress group,while the intercellular carbon dioxide concentration increased with the severity of drought stress. With the treatment time,the initial fluorescence was higher in the severe drought stress group than in the control group,and the moderate drought stress group was lower than the control group,the maximum fluorescence was significantly lower in the severe drought stress group than in the control group, potential photochemical efficiency and maximum photochemical efficiency were significantly elevated in the moderate drought stress group. Conclusion:Drought stress can significantly inhibit the growth of A. senticosus. Severe drought conditions can significantly inhibit the photosynthesis of A. senticosus leaves. This effect is related to the regulation of stomatal size,but not related to the activity of photoreaction center.

Chinese Journal of Biotechnology ; (12): 1229-1236, 2021.
Article in Chinese | WPRIM | ID: wpr-878626


Lactate is an important industrial chemical and widely used in various industries. In recent years, with the increasing demand for polylactic acid (PLA), the demand for lactate raw materials is also increasing. The contradiction between the high cost and the market demand caused by the heterotrophic production of lactate attracts researchers to seek other favorable solutions. The production of lactate from photosynthetic carbon fixation by cyanobacteria is a potential new raw material supply strategy. Based on the photosynthetic autotrophic cell factory, it can directly produce high optical purity lactate from carbon dioxide on a single platform driven by solar energy. The raw materials are cheap and easy to obtain, the process is simple and controllable, the products are clear and easy to separate, and the double effects of energy saving and emission reduction and production of high value-added products are achieved at the same time, which has important research and application value. This paper reviews the development history of cyanobacteria carbon sequestration to produce lactate, summarizes its research progress and encounters technical difficulties from the aspects of metabolic basis, metabolic engineering strategy, metabolic kinetics analysis and technical application, and prospects the future of this technology.

Carbon Cycle , Carbon Dioxide , Cyanobacteria/genetics , Lactic Acid , Metabolic Engineering , Photosynthesis
Ciênc. rural (Online) ; 51(10): e20200549, 2021. tab
Article in English | LILACS-Express | LILACS, VETINDEX | ID: biblio-1278861


ABSTRACT: Macronutrient suppression is one way to identify which chemical elements is the most important in the early development of seedlings of forest species. This study evaluated the initial growth of Eucalyptus benthamii seedlings through morphological and physiological variables, submitted to doses of N, P and K, and liming. The experimental design to install the experiment was completely randomized, with a 2x9 factorial scheme, in which levels of factor "A" referred to absence and presence of liming and levels of factor "B", to the different treatments of NPK. Morphological variables of SD (stem diameter) and H (height) and the physiological variables of A (photosynthesis), E (transpiration), gs (stomatal conductance), Ci/Ca (relationship between intercellular and atmospheric CO2 concentration) and WUE (water use efficiency) were measured. For morphological variables, the absence of N directly affected the means and there was a direct relationship between increase of the dose and increase of SD and H. There was a positive relationship of P mainly in relation to shoot dry matter content (SDMC) and root dry matter content (RDMC). For the physiological variables, there was no direct response with the doses of N or P, with K being the element that most influenced the variables, especially when limestone was applied, resulting in higher averages for photosynthesis, transpiration and stomatal conductance. With the purpose of meeting the morphological and physiological demands, the recommendation for cultivation of Eucalyptus benthamii under the conditions of this study is the doses 150-200-150, without liming application.

RESUMO: A supressão dos macronutrientes é uma das maneiras de identificar qual ou quais dos elementos químicos é o mais importante no desenvolvimento inicial das mudas de espécies florestais. O estudo objetivou avaliar o crescimento inicial de mudas de Eucalyptus benthamii por meio de variáveis morfológicas e fisiológicas, submetidas a doses de N, P e K, e calagem. O delineamento experimental para instalação do experimento foi em delineamento inteiramente casualizado, com esquema fatorial 2x9, em que os níveis do fator "A" se referiram a ausência e a presença de calagem e os níveis do fator "B" aos diferentes tratamentos de NPK. Variáveis morfológicas de DAC (diâmetro a altura do colo) e H (altura) e as variáveis fisiológicas de A (fotossíntese), E (transpiração), gs (condutância estomática), Ci/Ca (relação entre a concentração intercelular e atmosférica de CO2) e WUE (eficiência no uso da água) foram determinadas. Para as variáveis morfológicas, a ausência do N afetou diretamente as médias, havendo uma relação direta entre o aumento da dose com o aumento das variáveis. Há uma relação positiva do P principalmente em relação a MSPA e MSPR. Para as variáveis fisiológicas, não houve resposta direta com as doses de N ou P, sendo o K o elemento que mais influenciou as variáveis, principalmente quando o calcário foi aplicado, resultando em maiores médias para fotossíntese, transpiração e condutância estomática. Com o objetivo de atender às demandas morfológicas e fisiológicas, a recomendação para o cultivo de Eucalyptus benthamii nas condições deste estudo é a dose 150-200-150, sem aplicação de calagem.

Braz. arch. biol. technol ; 64: e21190580, 2021. tab, graf
Article in English | LILACS | ID: biblio-1285547


HIGHLIGHTS Azospirillum brasilense stimulates root growth in maize under water deficit. Maize inoculated with A. brasilense shows greater photosynthesis under drought conditions. Under water deficit, maize plants inoculated with A. brasilense showed greater water use efficiency (WUE).

Abstract The objective of this study was to evaluate the gas exchange, root morphology and nutrient concentration in maize plants inoculated with A. brasilense under two water conditions. The experiments were carried out in a greenhouse, one under irrigation and the other under water deficit. The treatments consisted of four A. brasilense inoculants (control (without inoculation), Az1 (CMS 7 + 26), Az2 (CMS 11 + 26) and Az3 (CMS 26 +42). At the V6 plant stage, water stress was imposed on maize plants for 15 days. The phytotechnical characteristics, gas exchange, root morphology, root dry matter and macronutrient analysis were evaluated after 15 days of water deficit imposition. The water deficit caused a reduction in the development of maize plants. The presence of A. brasilense Az1 under the same condition yielded higher photosynthesis, carboxylation efficiency, water use efficiency, and greater soil exploration with increased length, surface area and root volume of plants. Inoculation by A. brasilense increased root system volume by an average of 40 and 47% under irrigation and water deficit, respectively, when compared to non-inoculated plants. The inoculant Az1 attenuated the deleterious effects caused by drought and yielded the best growth of the root system, resulting in the tolerance of maize plants to water deficit.

Photosynthesis , Water Consumption (Environmental Health) , Zea mays , Efficient Water Use/methods
Biosci. j. (Online) ; 36(1): 152-160, jan./feb. 2020. graf, tab
Article in English | LILACS | ID: biblio-1049228


The knowledge of gas exchanges in forage plants is essential for a better understanding of the process of forage biomass production in pasture. This study evaluated the gas exchange in massai grass fertilized with increasing levels of nitrogen fertilizer (control - without nitrogen fertilizer; 400; 800 and 1200 kg ha-1year-1) and under rotational grazing by sheep, in a completely randomized design with repeated measures in time. The rest period was approximately 1.5 new leaves per tiller, as determined in the pre-test at the beginning of the experiment, providing interval of 22; 18; 16 and 13 days for the levels 0.0 - control; 400; 800 and 1200 kg ha-1 year-1 nitrogen, respectively. The animals used to lower the sward height to the recommended residual height were sheep (½ Morada Nova x ½ undefined breed), placed in paddocks of 42.3 m2. As the animals grazed, the height of the sward was monitored with a ruler until the canopy reached the recommended residual height of approximately 15 cm, corresponding to the residual LAI of exit of the animals from the paddock at approximately 1.5, as determined in a pre-test to set up the experiment. The variables stomatal conductance, leaf photosynthesis rate, leaf carbon dioxide concentration, photosynthesis/transpiration ratio, chlorophyll relative index and nitrogen sufficiency index revealed a positive linear response to nitrogen fertilization. Nitrogen fertilization level at 1200 kg ha-1year-1 caused an increment of 92.3% in leaf photosynthesis rate in relation to the control. The leaf temperature and photosynthesis/conductance ratio were reduced with increasing nitrogen levels. The leaf transpiration showed a quadratic response with maximum point with increasing nitrogen levels. Nitrogen fertilization favor the gas exchange in massai grass up to the last level tested.

O conhecimento das trocas gasosas em plantas forrageiras é essencial para melhor entendimento de como ocorre o processo de produção de biomassa de forragem na pastagem. Objetivou-se avaliar as trocas gasosas no capim-massai submetido a crescentes doses de nitrogênio (controle - sem nitrogênio; 400; 800 e 1200 kg ha-1 ano-1) e sob lotação rotativa com ovinos, num delineamento inteiramente casualizado com medidas repetidas no tempo. O período de descanso adotado foi de aproximadamente 1,5 novas folhas por perfilho, conforme determinação em pré-ensaio quando do início da instalação do experimento, propiciando um intervalo de 22; 18; 16 e 13 dias para as doses 0,0 ­ controle; 400; 800 e 1200 kg ha-1 ano-1 de nitrogênio, respectivamente. Os animais utilizados para rebaixamento do pasto até a altura residual preconizada foram ovinos (½ Morada Nova x ½ SPRD), alocados em piquetes de 42,3 m2. À medida que os animais pastejavam, a altura do pasto foi monitorada com auxílio de uma régua, até que o dossel atingisse a altura residual preconizada de aproximadamente 15 cm, correspondendo ao IAF residual de saída dos animais do piquete de aproximadamente 1,5, conforme determinação em pré-ensaio para instalação do experimento. As variáveis: condutância estomática, taxa de fotossíntese foliar, concentração interna de CO2, relação fotossíntese/transpiração, índice relativo de clorofila e índice de suficiência de nitrogênio responderam de forma linear crescente ao incremento nas doses de nitrogênio. Verificou-se aumento de 92,3% na taxa de fotossíntese para a dose de N de 1200 kg ha-1 ano-1 em relação à ausência de nitrogênio. A temperatura da folha e a relação fotossíntese/condutância foram reduzidas com o aumento das doses de nitrogênio. A adubação nitrogenada proporcionou resposta quadrática com ponto de máximo sobre a taxa de transpiração foliar. A adubação nitrogenada favorece as trocas gasosas em capim-massai até a última dose estudada.

Photosynthesis , Sheep , Biomass , Panicum , Nitrogen
Ciênc. rural (Online) ; 50(4): e20180911, 2020. graf
Article in English | LILACS-Express | LILACS | ID: biblio-1089571


ABSTRACT: Herbicide application is an effective weed control method for mitigating crop yield loss; however, herbicide overuse can cause toxicity in non-target plants. The present study evaluated the effects of glufosinate at recommended dose for agricultural application (0.45 kg ha-1) and at overuse dose (0.90 kg ha-1) glufosinate application on photosynthetic performance and nitrogen assimilation of the rapeseed varieties D148 and Zhongshuang 11 (ZS11). Both glufosinate concentrations significantly decreased the content of chlorophyll and nitrogenous compounds, except free proline, and the activity of glutamine synthetase and glutamate synthase, and increased the activity of glutamic acid dehydrogenase in both varieties. When the concentration of glyphosate was 0.45kg ha-1, the nitrogen assimilation of the two varieties decreased, which indicated that the recommended dosage inhibited the nitrogen assimilation of the two varieties; however, the increase of net photosynthetic rate of D148 and the decrease of that of ZS11 mean that D148 is more tolerant to the recommended dose of glyphosate than ZS11. The 0.90 kg ha-1 dosage was toxic to both rapeseed varieties. Overall, our results indicated that herbicide overuse inhibited the photosynthetic rate and nitrogen assimilation in rapeseed seedlings, and it is essential to apply a suitable glufosinate dose based on the variety grown to minimize adverse effects on crops and environment.

RESUMO: A aplicação de herbicidas é um método eficaz de controle de ervas daninhas para mitigar a perda de produtividade das culturas. No entanto, o uso excessivo de herbicidas pode causar toxicidade em plantas não alvo. O presente estudo avaliou os efeitos da dose recomendada para aplicação agrícola (0.45 kg ha-1) e dose excessiva (0.90 kg ha-1) de glufosinato no desempenho fotossintético e assimilação de nitrogênio das variedades de colza D148 e Zhongshuang 11 (ZS11). Ambas as concentrações de glutamato diminuíram significativamente o teor de clorofila e compostos azotados, exceto a prolina livre, e a atividade de síntese da glutamina e de síntese de glutamato, e aumentaram a atividade de desidrogenase do ácido glutâmico em ambas as variedades. Quando a concentração de glifosato foi 0.45 kg ha-1, a assimilação de azoto das duas variedades diminuiu, o que indicou que a dosagem recomendada de glifosato inibiu a assimilação de azoto das duas variedades de colza. Entretanto, a taxa fotosintética líquida do D148 aumentou enquanto o do ZS11 diminuiu, o que significa que o D148 é mais tolerante a dose recomendada de glifosato do que o ZS11. A dose de 0.90 kg ha-1 de glifosato foi prejudicial para as mudas de duas variedades de colza. Em geral, os nossos resultados indicam que o uso excessivo de glufosinato inibe a taxa fotossintética e a assimilação de nitrogênio em mudas de colza, sendo essencial aplicar uma dose adequada deste herbicida com base na variedade cultivada para minimizar os efeitos adversos nas culturas e no meio ambiente.

Biol. Res ; 53: 37, 2020. tab, graf
Article in English | LILACS | ID: biblio-1131883


BACKGROUND: Soil salinity causes huge economic losses to agriculture productivity in arid and semiarid areas world-wide. The affected plants face disturbances in osmotic adjustment, nutrient transport, ionic toxicity and reduced photosynthesis. Conventional breeding approaches produce little success in combating various stresses in plants. However, non-conventional approaches, such as in vitro tissue culturing, produce genetic variability in the development of salt-tolerant plants, particularly in woody trees. RESULTS: Embryogenic callus cultures of the date palm cultivar Khalas were subjected to various salt levels ranging from 0 to 300 mM in eight subcultures. The regenerants obtained from the salt-treated cultures were regenerated and evaluated using the same concentration of NaCl with which the calli were treated. All the salt-adapted (SA) regenerants showed improved growth characteristics, physiological performance, ion concentrations and K+/Na+ ratios than the salt non-adapted (SNA) regenerants and the control. Regression between the leaf Na+ concentration and net photosynthesis revealed an inverse nonlinear correlation in the SNA regenerants. Leaf K+ contents and stomatal conductance showed a strong linear relationship in SA regenerants compared with the inverse linear correlation, and a very poor coefficient of determination in SNA regenerants. The genetic fidelity of the selected SA regenerants was also tested using 36 random amplified polymorphic DNA (RAPD) primers, of which 26 produced scorable bands. The primers generated 1-10 bands, with an average of 5.4 bands per RAPD primer; there was no variation between SA regenerants and the negative control. CONCLUSION: This is the first report of the variants generated from salt-stressed cultures and their potential adaptation to salinity in date palm cv. Khalas. The massive production of salt stress-adapted date palm plants may be much easier using the salt adaptation approach. Such plants can perform better during exposure to salt stress compared to the non-treated date palm plants.

Salt Tolerance/genetics , Phoeniceae/genetics , Acclimatization , Random Amplified Polymorphic DNA Technique , Salinity
Article in Chinese | WPRIM | ID: wpr-872837


Objective:To study the effect of different shading conditions on the growth and photosynthetic physiological parameters of Acanthopanax senticosus,and provide a theoretical basis for standardized planting and rational development and utilization of A. senticosus. Method:Three-year-old A. senticosus was used as the experimental sample.The growth parameters and photosynthetic physiological parameters of plant height,leaf number and leaf area were determined to study the effects of different shading conditions on the growth and photosynthesis of A. senticosus. Result:Plant height,leaf number,and leaf area were significantly higher in the shading treatment than in the control group,and highest under moderate shading conditions.The net photosynthetic rate,stomatal conductance,and transpiration rate were significantly higher in the moderate shading group than in the control group,and decreased in the severe shading group,while the intercellular carbon dioxide concentration was significantly lower in the moderate shading group than in the other treatment groups.As the treatment time progressed,the initial fluorescence was not significantly higher in the moderate shading group than in the control group,but significantly higher in the severe shading group;the maximum fluorescence was significantly higher in the shading group than in the control group,in the moderate shading group.The potential photochemical efficiency and maximum photochemical efficiency were not significantly different between the moderate shading group and the control group and decreased in the severe shading group,which was significantly lower than other treatment groups. Conclusion:Shading treatment is beneficial to the growth of A. senticosus.The moderate shading condition can significantly improve the photosynthesis of A. senticosus.Severe shading treatment can significantly inhibit the photosynthesis of A. senticosus leaves.This effect is related to the regulation of stomatal regulation. The activity of the photoreaction center is related.

Article | IMSEAR | ID: sea-204834


A rice variety Jyothi (PTB 39) is a red kernelled with bold grain, popular in the region of Kerala, India used in the study. Plants were grown in pots under three different conditions, natural solar UV-B conditions, UV-B excluded condition using UV-B filters and supplemental UV-B using UV-B lamps along with ambient solar radiation. During the study period, UV-B radiation was in the range of 1.30 to 3.58 Wm2 which affected the productivity of the crop under open solar condition. A decrease in morphological traits like plant height, number of tillers, flag leaf angle and increase in leaf thickness were observed. Physiological parameters, leaf gas exchange parameters and biochemical constituents such as chlorophyll content also recorded less value under high UV-B condition along with the high content of protective compounds such as flavonoid content, catalase and PAL activity. The phenophases of the crop were also delayed by 4-5 days under UV-B radiation exposed conditions. All these negative impacts of UV-B radiation on crop leads to restricted filling of grain, lesser harvest index and grain development leading to a decrease in yield and yield attributing characters.

Biosci. j. (Online) ; 35(3): 691-704, may./jun. 2019. graf, tab
Article in English | LILACS | ID: biblio-1048627


The occurrence of seasonal droughts is one of the main factors that limit the sugarcane ratoon cycles, compromising sugarcane field longevity. The aim of this study was to evaluate the biochemical responses of sugarcane cultivars to drought stress in ratoon crop. Six cultivars were used: RB72910, RB99382, RB72454, RB92579, RB855536 and RB931011, and three water regimes based on soil available water content(SAWC) and defined as: control, 80 to 100% (SAWC); moderate water stress, 40 to 60% (SAWC), and severewater stress, 0 to 20% (SAWC). Cultivar RB72454 was most sensitive to water deficit. When under stress, this cultivar showed an increased production of hydrogen peroxide, but without concomitant increase in the activity of the antioxidant enzymes ascorbate peroxidase, catalase and superoxide dismutase. Oxidative stress led to lipid peroxidation and chlorophyll degradation, resulting in higher photochemical photoinhibition. On the other hand, cultivar RB92579 was the most tolerant to drought, with increased activity of antioxidant enzymes, which led to low lipid peroxidation, maintenance of photosynthetic pigments and photochemical activity. The antioxidant defense system triggered by ascorbate peroxidase, catalase and superoxide dismutase enzymes appears to be a key protection factor to photochemical complexes of chloroplast of sugarcane plants under water stress. The increase in the antioxidant system as well as the maintenance of photosynthetic pigments and cell membranes served as important criteria to indicate cultivars more tolerant to drought stress.

A ocorrência de secas sazonais é um dos principais fatores que limitam a longevidade do canavial. Esse trabalho teve como objetivo avaliar as respostas bioquímicas de cultivares de cana-de-açúcar em seu segundo ciclo de cultivo a condições de estresse hídrico. Para tanto, foram utilizadas seis cultivares: RB72910, RB99382, RB72454, RB92579, RB855536 e RB931011, e três regimes hídricos, baseado na capacidade de água disponível (CAD) e definidos como: controle, 80 a 100% (CAD); estresse hídrico moderado, 40 a 60% (CAD), e estresse hídrico severo, 0 a 20% (CAD). A cultivar RB72454 se mostrou a mais sensível ao déficit hídrico. Essa cultivar mostrou aumento na produção de peróxido de hidrogênio, mas sem aumento concomitante das enzimas antioxidantes ascorbato peroxidase, catalase e superóxido dismutase. Esse estresse oxidativo levou a peroxidação de lipídeos das membranas e degradação das clorofilas, resultando na diminuição da eficiência fotoquímica do PSII. Por outro lado, a cultivar RB92579 foi a mais tolerante à seca, com aumento de atividade das enzimas antioxidantes, que levou a baixa peroxidação de lipídeos, manutenção dos pigmentos fotossintéticos e da eficiência fotoquímica do PSII. O sistema de defesa antioxidante desencadeado pelas enzimas ascorbato peroxidase, catalase e superóxido dismutase parece ser o fator chave de proteção à fotoinibição de plantas de cana-de-açúcar sob estresse hídrico. O aumento do sistema antioxidante, bem como a manutenção dos pigmentos fotossintéticos e das membranas celulares serviram como critérios importantes para indicar cultivares mais tolerantes ao estresse hídrico.

Photosynthesis , Chlorophyll , Photooxidation , Dehydration , Saccharum
Article | IMSEAR | ID: sea-188020


Aims: To characterize the growth, carbon assimilation and quality of Ipomoea aquatica as influenced by magnetic nanoparticles (MNP) application as well as to determine the best rates of iron oxide nanoparticles that give high growth, carbon assimilation and quality of Ipomoea aquatica. Study Design: Ipomoea aquatica plants were exposed to four different treatments of magnetic iron oxide nanoparticles (Fe3O4) (0, 50, 100 and 150 mg L-1). The experiment was conducted in a randomized complete block design (RCBD) with 3 replications. One unit of experiment consisted of 8 plants and there were 96 plants used in the experiment. Place and Duration of Study: Department of Biology, Faculty of Science, Universiti Putra Malaysia, between March 2018 and July 2018. Methodology: The growth parameters measured included: plant height, basal diameter, total leaf number, leaf temperature, total chlorophyll content and plant biomass. The carbon assimilation parameters were measured using IRGA (Infrared Gas Analyzer, LICOR 6400 XT Portable Photosynthesis System). i.e. transpiration rate (E), stomatal conductance and water use efficiency (WUE). The chlorophyll fluorescence were measured by using Pocket PEA that measured maximum efficiency of photosystem ii, (fv/fm), maximum quantum yield of phytochemical and non-photochemical process in photosystem II (fv/fo), minimal fluorescence (fo), performance index (PI) and Density of Reaction Centers Per PSII Antenna Chlorophyll (RC/ABS). Total phenolics and flavonoids contents in leaves were measured using Folin-Ciocalteu method. Results: It was observed that plant height, shoot length, plant temperature, total biomass, and total chlorophyll content were significantly influenced (p≤0.05) by the different concentrations of magnetic nanoparticles. The net photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), maximum efficiency of photosystem II (Fv/fm), maximum quantum yield of phytochemical and non-photochemical process in photosystem II (Fv/fo), performance index and the density of reaction centers per PSII antenna chlorophyll of Ipomoea aquatica were significantly reduced at higher concentration of magnetic nanoparticles. However, water use efficiency and minimal fluorescence value (Fo) of Ipomoea aquatica increased with increase of MNP concentration. In addition, the application of magnetic nanoparticles significantly influenced (P≤0.05) the total flavonoids and total phenolics content in water spinach. Both of these parameters were increased when higher concentration of magnetic nanoparticles was applied to Ipomoea aquatica. This study showed that MNP affected the growth, carbon assimilation and secondary metabolites production of Ipomoea aquatica. Conclusion: In conclusion, the higher concentration of magnetic nanoparticles reduced the growth rate and carbon assimilation of water spinach and enhanced the production of secondary metabolites.