Photosynthetic physiological characteristics of Angelica dahurica var.formosana from Sichuan province in different growth years / 中国中药杂志

In this study,the leaves of autumn-sown Angelica dahurica var. formosana from Sichuan province in different growth years was used to explore the fitting model of photosynthetic response curve and the different photosynthetic physiological characteristics between annual and biennial A. dahurica var. formosana from Sichuan province. The results showed that the fitting model of the optimum light response curve of the leaves of A. dahurica var. formosana from Sichuan province with different growth years was all rectangular hyperbolic correction model. The light saturation points were 1 600,1 700 μmol·m-2·s-1,the light compensation points were17. 98,52. 23 μmol·m-2·s-1 in the leaves of annual and biennial plant,respectively. The diurnal variation curves of net photosynthetic rate,transpiration rate and stomatal conductance in the leaves all acted as a single peak value wave. The daily mean values of net photosynthetic rate and transpiration rate in the leaves of biennial plant were significantly higher than that of annual plant. There was no significant difference in daily mean stomatal conductance. The net photosynthetic rate was significantly positively correlated with stomatal conductance in both of the different growth years. The net photosynthetic rate of annual and biennial A. dahurica var. formosana from Sichuan province had extremely significant and significantly negative correlation with the intercellular CO2 respectively. The transpiration rate of annual plant was positively correlated with the effective photosynthetic radiation intensity and air temperature,but had significantly negative correlation with the intercellular CO2 concentration. The transpiration rate of biennial plant had extremely positive correlation with the effective photosynthetic radiation intensity,and negatively correlated with the intercellular CO2 concentration. In conclusion,the photosynthetic efficiency of the leaves in biennial plant of A. dahurica var. formosana from Sichuan province was higher than that in annual plant,but the ability to utilize weak light was lower than that of annual plant. It should be planted in the sunny field.

Response of growth and photosynthetic characteristics of Polygonatum cyrtonema to shading conditions / 中国中药杂志

The purpose of this experiment was to study the effects of different shading conditions on the growth,physiological characteristics and biomass allocation of Polygonatum cyrtonema,which offered a theoretical basis for its cultivation.Different light environments(100%,80%,60% and 35% light transmittance) were simulated with shading treatments.Growth and photosynthetic indexes of P.cyrtonema were measured and the variances were analyzed.The results show that shading decreased superoxide anion radical(O-·2)production rate and hydrogen peroxide(H_2O_2) accumulation,kept the activity of SOD,POD and CAT enzyme at a high level.Furthermore,The content of chlorophyll a and chlorophyll b,net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),maximal photochemical efficiency of photosystem Ⅱ(Fv/Fm),photochemical quenching index(q P) and effective quantum yield of photosystem II(ΦPSⅡ) of P.cyrtonema were increased while the intercellular CO2 concentration(Ci),Foand NPQ were decreased by shading.Shading is beneficial to P.cyrtonema growth,can increase the total biomass P.cyrtonema.The allocation proportion of biomass on the aerial portion of P.cyrtonema increased but underground parts decreased with increasing shading conditions.In this study,P.cyrtonema can grow well in shading conditions,shading is beneficial to the formation of the yield and quality of the rhizomes of P.cyrtonema,especially in 65% light transmittance.

Study on membrane type leaf water evaporation inhibitors for improving effect of preventing diseases and pest controlling of / 中国中药杂志

Through indoor and field comparative experiments, the properties of membrane type leaf evaporation inhibitors and its effects on photosynthesis of and compatibility and synergistic of pesticide were studied. The evaporation inhibitors and were chosen to investigate the suppression of water evaporation and the compatibility with pesticides. The effect of evaporation inhibitors on photosynthesis of leaves was determined by the chlorophyll fluorescence imaging system. The results showed that water evaporation of leaves of different leaf age were evidently suppressed after treated with evaporation inhibitor. The inhibitor was well compatible with pesticide and effectively improved the pesticide efficacy，and had no significant effect on chlorophyll fluorescence parameters. It is concluded that the evaporation inhibitor has good compatibility with the pesticide, and has remarkable effect of restraining moisture evaporation, which make it can be used for reducing the dosage and improving the efficacy of the pesticide in the field of

Photosynthetic capacity and water use efficiency in Ricinus communis (L) under drought stress in semi-humid and semi-arid areas

ABSTRACT Castor bean is one of the crops with potential to provide raw material for production of oils for biodiesel. This species possess adaptive mechanisms for maintaining the water status when subjected to drought stress. A better understanding these mechanisms under field conditions can unravel the survival strategies used by this species. This study aimed to compare the physiological adaptations of Ricinus communis (L.) in two regions with different climates, the semi-arid and semi-humid subject to water stress. The plants showed greater vapor pressure deficit during the driest hours of the day, which contributed to higher values of the leaf temperature and leaf transpiration, however, the VPD(leaf-air) had the greatest effect on plants in the semi-arid region. In both regions, between 12:00 p.m. and 2:00 p.m., the plants presented reduction in the rates of photosynthesis and intracellular CO2 concentration in response to stomatal closure. During the dry season in the semi-arid region, photoinhibition occurred in the leaves of castor bean between 12:00 p.m. and 2:00 p.m. These results suggest that castor bean plants possess compensatory mechanisms for drought tolerance, such as: higher stomatal control and maintenance of photosynthetic capacity, allowing the plant to survive well in soil with low water availability.

Morpho-physiological analyses of Allamanda blanchetii A. DC. seedlings under water deficit / Análises morfo-fisiológicas em plantas de Allamanda blanchetii A. DC sob déficit hídrico

The Allamanda blanchetii belongs to the Apocynaceae family, being an ornamental species popularly known as allamanda-roxa and is endemic to the Caatinga. The aim of this research was to evaluate the growth, gas exchange, relative water content, and stomatal density of A. blanchetii under water stress conditions. The experimental design was completely randomized with six levels of the maximum water holding capacity (MWHC) (100%, 80%, 60%, 40%, and 20%) with eight replications. Weekly, it was performed the evaluations of plant height and number of leaves. The results for water stress treatment in the A. blanchetii plants show that they develop better in the water levels of 100% and 80% of the MWHC, without presenting significant morphological and physiological changes. In turn, 20% of the MWHC does not allow the survival of the A. blanchetii plants. The water restriction negatively interfered in the gas exchange in the treatment of 60% and 40% of the MWHC. Therefore, it can be concluded that the A. blanchetii plants grow satisfactorily in 100% and 80% of the MWHC, ensuring the growth and survival during the drought period. The water availability to which the plants were submitted does not influence the total chlorophyll and relative water content of leaves. Gas exchanges are adversely affected at levels of water availability below 80% of the MWHC.

Allamanda blanchetii pertence à família Apocynaceae, é uma espécie ornamental, conhecida popularmente como allamanda-roxa, endêmica da Caatinga. O objetivo da pesquisa foi avaliar o crescimento, trocas gasosas, conteúdo relativo de água e densidade estomática de A. blanchetii sob condições de estresse hídrico. O delineamento experimental foi inteiramente casualizado, com seis capacidade máxima de retenção de água tratamentos hídricos (100%, 80%, 60%, 40% e 20%) com oito repetições. Os resultados obtidos sobre o déficit hídrico aplicado, as plantas de A. blanchetii se desenvolvem com níveis de água de 100% e 80% da CMRA, sem apresentar modificações morfológicas e fisiológicas significativas enquanto que com de 20% da CMRA não houve a sobrevivência de plantas. A restrição hídrica interferiu negativamente nas trocas gasosas, nos tratamentos de 60% e 40% CMRA. Portanto pode-se concluir que as plantas de A. blanchetii crescem satisfatória sob 100% e 80% CMRA garantindo a sua sobrevivência e crescimento durante a seca. A clorofila total e o teor relativo de água na folha das plantas não foram influenciados pelos regimes hídricos a que foram submetidas. As trocas gasosas são negativamente afetadas em níveis de disponibilidade hídrica abaixo de 80% da CMRA.

Effect of water stress in partial root zone on response of photosynthesis of Aconitum barbatum / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effect of different water stress mode on photosynthesis characteristics of Aconitum barbaturnm, aimed at providing the theoretical basis for cultivating this kind of plant for the arid area.</p><p><b>METHOD</b>The transplanted seedlings of A. barbatum were processed with fixed partial root zone drying(TI) ,alternate partial root zone drying(T2) and both partial root zone irrigation (T3) for three cycles,and relative parameters were measured.</p><p><b>RESULT</b>The net photosynthetic rate (Pn) in the treatment of T2 gradually increased and was higher than that in the treatment of T3 about 6.53%, mainly effected by non-stomatal factors. The water use efficiency (WUE) was higher than that in the treatments of T3 about 25.21%, while the transpiration rate (Tr) and the stomatal conductance was lower than those in the treatment of T1 and T3 separately. The maximum net photosynthesis rate (Pmax),the apparent quantum yield (AQY) and the dark respiration rate (Rd) were higher than those in comparison condition slightly.</p><p><b>CONCLUSION</b>The alternate partial root zone drying is worth promoting vigorously, and it shall be a rational way to cultivate the A. barbatum under woodland.</p>

Effect of different soil water treatments on physiological characteristics and yield of Artemisia annua / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effect of water content in soil on physiological characters and yield of Artemisia annua.</p><p><b>METHOD</b>The pot experiment was applied and activity of protective enzyme, biomass and artemisinin accumulation were measured under different water treatments.</p><p><b>RESULT AND CONCLUSION</b>The results showed that contents of osmotic adjustable substances, activity of protective enzyme, biomass and artemisinin accumulation were greatly affected by water content in the soil. Under water stress the water content in leave decreased, relative plasmalemma permeability increased, proline quickly accumulated to promote water retaining capability of cell, POD, CAT and SOD cooperated to reduce lipid peroxidation and reduced cell damage, and biomass decreased. At the seedling stage, the content of artemisinin and yield reached the maximal when the water content in soil was between 50%-55%. At the beginning of the branching stage, the content of artemisinin was the highest at the water content of 50%-55%, while the yield reached the maximal at the water content of 70%-75%. At the end of branching stage, the content of artemisinin was the highest at the water content of 40%-45%, while the yield reached the maximal at the water content of 60%-65%. In conclusion, the optimum water content in soil was between 50%-55% at the seedling stage, at the branching stage, higher water content was beneficial for the higher yield.</p>

Effect of water stress on content of active constituents in Erigeron breviscaps / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effect of water stress on the content of scutellarin and caffeate in Erigeron breviscaps.</p><p><b>METHOD</b>Fv/Fm, N content, as well as the content of scutellarin and caffeate under three water grads were measured.</p><p><b>RESULT AND CONCLUSION</b>Fv/Fm of the plant decreased significantly in 8% and 23% water treatment, that proved drought and waterlogging occurred. Under the two conditions, the contents of N were lower but the contents of active constituents were higher than those under 15% treatment. The results support the carbon-nutrient balance hypothesis and the "stress effect hypothesis" for the formation of geo-herbs.</p>

Fotossíntese, condutância estomática e potencial hídrico foliar em árvores jovens de andiroba (Carapa guianensis) / Photosynthesis, stomatal conductance and leaf water potential in crabwood (Carapa guianensis)

O potencial hídrico da folha é um dos fatores mais importantes que afetam o funcionamento dos estômatos. O objetivo deste trabalho foi avaliar o efeito da variação diurna na irradiância e déficit de pressão de vapor (DPV) na fotossíntese (A), condutância estomática (g s) e potencial hídrico da folha (psi) em Carapa guianensis (Aubl.). Os dados foram coletados de 07:00 às 17:00 h. A taxa fotossintética atingiu um valor máximo (2,5 æmol m-2 s-1) às 10:00 h, depois declinou até atingir um mínimo de 1 æmolm-2 s-1 às 16:00 h. A condutância estomática oscilou durante o dia, de 0,04 molm-2s-1 (ao meio dia) para 0,02 molm-2s- 1 no final da tarde. O potencial hídrico da folha foi máximo nas primeiras horas do dia (-0,3 MPa) e mínimo (-0,75 MPa) no meio da tarde (14:30 a 15:00 h). Após ter alcançado um mínimo, o psi aumentou até -0,64 MPa no fim da tarde. A taxa fotossintética aumentou linearmente em função do g s (P < 0,01). Também houve uma relação positiva entre psi e g s (P < 0,01). A taxa fotossintética declinou durante o dia após ter alcançado um pico no início da manhã, demonstrando que os fatores ambientais que afetam o psi têm efeito significativo na assimilação do carbono de C. guianensis.

Leaf water potential is one of the most important factors affecting stomatal functioning. The aim of this study was to assess the effect of variation in diurnal irradiance and vapour pressure deficit on photosynthesis (A), stomatal conductance (g s) and leaf water potential (psi) in Carapa guianensis (Aubl.). Data were collected from 07:00 to 17:00 h. Photosynthetic rates reached a maximum (2.5 æmol m-2 s-1) at 10:00 h, thereafter declined to a minimum of 1 æmol m-2 s-1 at 16:00 h. Stomatal conductance oscillated during the day, from 0.04 mol m-2 s-1 (at midday) to 0.02.mol.m-2.s-1 at the end of the afternoon. Leaf water potential was higher early in the morning (-0.3 MPa) and lower (-0.75 MPa) at mid-afternoon (14:30 -15:00 h). After reaching a minimum, psi increased up to -0.64 MPa at sunset. Photosynthetic rates increased linearly as a function of g s (P < 0.01). Also there was a positive relationship between psi and g s (P< 0.01). Photosynthetic rates declined during the day after reaching a peak early in the morning, which makes clear that environmental factors that influence psi greatly affect carbon assimilation of C. guianensis.

Protection of ultrastructure in chilling-stressed banana leaves by salicylic acid / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

<p><b>OBJECTIVE</b>Chilling tolerance of salicylic acid (SA) in banana seedlings (Musa acuminata cv., Williams 8818) was investigated by changes in ultrastructure in this study.</p><p><b>METHODS</b>Light and electron microscope observation.</p><p><b>RESULTS</b>Pretreatment with 0.5 mmol/L SA under normal growth conditions (30/22 degrees C) by foliar spray and root irrigation resulted in many changes in ultrastructure of banana cells, such as cells separation from palisade parenchymas, the appearance of crevices in cell walls, the swelling of grana and stromal thylakoids, and a reduction in the number of starch granules. These results implied that SA treatment at 30/22 degrees C could be a type of stress. During 3 d of exposure to 7 degrees C chilling stress under low light, however, cell ultrastructure of SA-pretreated banana seedlings showed less deterioration than those of control seedlings (distilled water-pretreated).</p><p><b>CONCLUSION</b>SA could provide some protection for cell structure of chilling-stressed banana seedling.</p>

A new concept for insect damage evaluation based on plant physiological variables

The objective of this study was to determine the damage levels caused by Orthezia praelonga Douglas, 1891 and Leucoptera coffeella (Guérin-Mèneville 1842), on rangpur lime and Obatã coffee leaves, respectively. Measurements were based on a new concept for the evaluation of the following plant physiological parameters: photosynthesis, stomatal conductance, leaf temperature and transpiration, and internal concentration of CO2 (by infrared analyzer). A negative correlation between infestation level and photosynthesis was found, where the negative inflexion point of the curve was considered as a reference for damage levels. The control level for O. praelonga is below the 7-13 percent limit for damaged leaf area (40 to 70 scales per leaf), while for L. coffeella it is below the 26-36 percent limit for the same variable. Photosynthesis provided the best correlation for this type of analysis.

O objetivo deste trabalho foi estabelecer, baseado em um novo conceito de avaliação de parâmetros fisiológicos vegetais, o nível de dano causado por Orthezia praelonga Douglas 1891 e por Leucoptera coffeella (Guérin-Mèneville 1842) em folhas de limão cravo e cafeeiro 'Obatã', respectivamente. Foram feitas leituras de trocas gasosas por infravermelho, além da avaliação da condutância estomática, temperatura foliar, transpiração foliar e concentração interna de CO2. Os dados demonstraram uma correlação negativa entre o nível de infestação e a fotossíntese, sendo o ponto de inflexão negativa da curva tomado como referência de nível de dano, onde o nível de controle para O. praelonga encontra-se abaixo do limite de 7 a 13 por cento de área foliar lesionada (40 a 70 cochonilhas por folha), e o de L. coffeella encontra-se abaixo dos valores de 26 a 36 por cento de área foliar lesionada. Dentre os parâmetros avaliados a fotossíntese foi o que demonstrou melhor correlação para este tipo de análise.

Differential leaf gas exchange responses to salinity and drought in the mangrove tree Avicecennia germinans (Avicenniaceae)

Leaf gas exchange was assessed in Avicennia germinans L. grown under different NaCl concentrations (0-40 per thousand), after salt-relief, and then during drought. Stomatal conductance (gs) and net photosynthetic rate (Pn) decreased with increasing NaCl concentration, and intrinsic water use efficiency (Pn / gs) increased. Under desalinization Pn / gs declined. Thus, gs did not change in plants grown at low NaCl concentration (10 per thousand), but increased up to 30-32% at higher NaCl concentration (20-40 per thousand). However, Pn was only slightly enhanced (10-15%). Under drought, Pn decreased by as much as 46% in plants grown at low NaCl concentration (10 per thousand) and by 22% at high NaCl concentration (40 per thousand). Thus, Pn / gs decreased and water use efficiency was lower during drought compared to estimates prior to salt-relief.

Se estudió el intercambio de gases en las hojas de Avicennia germinans L. en varias concentraciones de NaCl (0-40‰), después de la desalinización y durante la desecación. La conductancia de los estomas (gs) y la tasa de fotosíntesis (Pn) decrecieron con el incremento en la concentración de NaCl, y se incrementó la eficiencia en el uso intrínseco de agua (Pn / gs). Bajo desalinización Pn / gs declinó. Así, gs no cambia en el crecimiento de las plantas a bajas concentraciones de NaCl (10‰), pero se incrementó hasta 30-32% a las concentraciones de NaCl más altas (20 - 40‰). Sin embargo, Pn aumentó ligeramente (10-15%). En desecación Pn fue reducido hasta un 46% a bajas concentaciones (10‰) de NaCl, y a un 22% a altas concentraciones (40‰) de NaCl. Así, Pn / gs decrecieron y la eficiencia en el uso de agua fue menor durante desecación en comparación con los evalolres stimados previos a la desalinización.

A Comparison of Sap Flow Measurements and Potometry in Two Tropical Lowland Tree Species with Contrasting Wood Properties

We evaluated the performance of the Heat Dissipation Technique (HDT) to measure sap flow in whole trees by comparison with potometric water uptake. Two tropical lowland species, Ochroma lagopus (balsa), a pioneer species with light wood and Hyeronima alchorneoides (pilón), a late-successional species with hard wood were examined. Diurnal courses of sap flow measured with the HDT showed good agreement with potometry. At the low sap flow rates (below 1 Kg h-1) occurring during nocturnal recharge HDT consistently underestimated sap flow rates. This resulted in the failure of the current version of the HDT to measure nocturnal water uptake, an important component of the water budget of at least one of the two species examined.

Effect of different mulch materials on winter wheat production in desalinized soil in Heilonggang region of North China / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Freshwater shortage is the main problem in Heilonggang lower-lying plain, while a considerable amount of underground saline water is available. We wanted to find an effective way to use the brackish water in winter wheat production. Surface mulch has significant effect in reducing evaporation and decreasing soil salinity level. This research was aimed at comparing the effect of different mulch materials on winter wheat production. The experiment was conducted during 2002~2003 and 2003~2004. Four treatments were setup: (1) no mulch, (2) mulch with plastic film, (3) mulch with corn straw, (4) mulch with concrete slab between the rows. The result indicated that concrete mulch and straw mulch was effective in conserving soil water compared to plastic film mulch which increased soil temperature. Concrete mulch decreases surface soil salinity better in comparison to other mulches used. Straw mulch conserved more soil water but decreased wheat grain yield probably due to low temperature. Concrete mulch had similar effect with plastic film mulch on promoting winter wheat development and growth.

Mecanismos de controle da variação sazonal da transpiração de uma floresta tropical no nordeste da amazônia / Control mechanisms of the seasonal variation of transpiration in a northeast amazonian tropical rainforest

No presente trabalho foram estudadas a variação sazonal da transpiração, de uma floresta tropical, e sua dependência com fatores bióticos e abióticos. Utilizaram-se dados do projeto CARBOPARA, parte integrante do Experimento de Grande Escala da Biosfera-Atmosfera na Amazônia (LBA), coletados na reserva florestal de Caxiuanã, região nordeste da Amazônia. A evapotranspiração total num intervalo de 39 dias para o período chuvoso foi 108,2 mm, com valor médio de 2,9 mm dia-1, enquanto, durante o período menos chuvoso, a evapotranspiração total num intervalo de 29 dias foi 128,8 mm, com média de 4,3 mm dia-1 para o período. Os valores máximos da condutividade de superfície (Cs), nos dois períodos, ocorreram às 08:00 hl, sendo estes valores de 0,060 m s-1 e 0,045 m s-1 para o período chuvoso e menos chuvoso, respectivamente. A condutância aerodinâmica média (Ca) foi 0,164 m s-1 e 0,210 m s-1, para os períodos chuvoso e menos chuvoso, respectivamente. Os valores máximos da Ca observados para os períodos chuvoso e menos chuvoso foram, respectivamente, 0,220 e 0,375 m s-1. Verificou-se que Cs guarda uma relação exponencial inversa com o déficit de vapor de água atmosférico, para diferentes intervalos de irradiância solar global. A análise horária do fator de desacoplamento sugere que a evapotranspiração, durante a manhã, tem um maior controle realizado pela disponibilidade de energia, quando comparado ao período menos chuvoso. Durante a tarde verifica-se que o dossel da floresta progressivamente tende a estar mais acoplado à atmosfera, para ambos os períodos estudados, demonstrando maior controle superficial na transpiração.

Metabolic responses of tropical trees to ozone pollution.

Plants fumigated with 40ppbv, 80ppbv and 120ppbv concentrations of O3 exhibited significant reduction in total chlorophyll content, RuBP carboxylase activity and net photosynthesis. The reduction in total chlorophyll activity ranged from 12 to 36% in Bauhinia variegata, 11 to 35% in Ficus infectoria and 3 to 26% in Pongamia pinnata on fumigation with O3, while the RuBP carboxylase activity was reduced by 10 to 32% in Bauhinia variegata, 10 to 23% in Ficus infectoria and 9 to 15% in Pongamia pinnata. The net photosynthesis was also reduced by 6 to 26% in B. variegata, 16 to 39% in F. infectoria and 7 to 31% in P. pinnata on fumigation with 03. The relative higher sensitivity of tropical trees to O3 suggests that the ambient air quality standards in tropical tree areas need to be stringent to prevent vegetation from air pollution.

Copper effect on photosynthesis and transpiration in safflower.

The young leaves of safflower plants subjected to deficient supply of copper (0.00063 mg Cu L-1) developed visible symptoms of Cu deficiency and showed a decrease in chlorophyll concentration, Hill activity, net photosynthesis and transpiration. On giving normal supply of Cu (0.063 mg Cu L-1), these changes were partially reversed.