Variation and interaction mechanism between active components in Rheum officinale and rhizosphere soil microorganisms under drought stress / 中国中药杂志

To explore the changes and the reaction mechanisms between soil microecological environment and the content of secon-dary metabolites of plants under water deficit, this study carried out a pot experiment on the 3-leaf stage seedlings of Rheum officinale to analyze their response mechanism under different drought gradients(normal water supply, mild, moderate, and severe drought). The results indicated that the content of flavonoids, phenols, terpenoids, and alkaloids in the root of R. officinale varied greatly under drought stresses. Under mild drought stress, the content of substances mentioned above was comparatively high, and the content of rutin, emodin, gallic acid, and(+)-catechin hydrate in the root significantly increased. The content of rutin, emodin, and gallic acid under severe drought stress was significantly lower than that under normal water supply. The number of species, Shannon diversity index, richness index, and Simpson index of bacteria in the rhizosphere soil were significantly higher than those in blank soil, and the number of microbial species and richness index decreased significantly with the aggravation of drought stresses. In the context of water deficit, Cyanophyta, Firmicutes, Actinobacteria, Chloroflexi, Gemmatimonadetes, Streptomyces, and Actinomyces were the dominant bacteria in the rhizosphere of R. officinale. The relative content of rutin and emodin in the root of R. officinale was positively correlated with the relative abundance of Cyanophyta and Firmicutes, and the relative content of(+)-catechin hydrate and(-)-epicatechin gallate was positively correlated with the relative abundance of Bacteroidetes and Firmicutes. In conclusion, appropriate drought stress can increase the content of secondary metabolites of R. officinale from physiological induction and the increase in the association with beneficial microbe.

Biological Mechanism of Drought Improving Quality of Rhizoma Atractylodis Chinensis / 中国实验方剂学杂志

ObjectiveTo explore the biological mechanism of drought improving the quality of Rhizoma Atractylodis Chinensis and establish a new method for the production of high-quality medicinal materials. MethodThe fresh roots of Atractylodes chinensis were soaked in 0 （control）， 5%， 10%， and 20% PEG-6000 solutions. The changes in reactive oxygen species （ROS） level， antioxidant enzyme activity， activities of key enzymes in primary metabolism and secondary metabolism， and content of secondary metabolites were compared. ResultCompared with the control group， the treatment with 20% PEG for 2 days elevated the levels of superoxide anion radicals （O2-·）， hydrogen peroxide （H2O2）， and malondialdehyde （MDA） by 172.5%， 56.9%， and 14.7%， respectively. The treatment did not change the activity of superoxide dismutase （SOD）， reduced the peroxidase （POD） activity， and increased the catalase （CAT） activity by 10.8%. It increased the activities of 3-hydroxy-3-methylglutaryl-CoA reductase （HMGR）， phosphoenolpyruvate carboxylase （PEPC）， and acetyl-CoA carboxylase （ACC） by 49.9%， 12.1%， and 19.0%， respectively. Furthermore， the content of atractylodin， β-eudesmol， atractylone， and atractylenolide Ⅱ was increased by 51.0%， 36.9%， 47.1%， and 91.5%， respectively. The simulated drought stress can cause the burst of ROS in the fresh roots of A. chinensis， induce the physiological state of plants under drought， change the antioxidant system， and promote the massive synthesis of secondary metabolites in a short time. ConclusionPEG-6000-simulated drought stress can greatly improve the quality of A. chinensis in cultivation.

Validating the physiological potential of zero monopodial compact cotton TCH 1819 culture by chemical manipulation

Cotton is the most important global cash crop which controls economy of many nations. Global sustainability of cotton yield is one of the major challenges for meeting impending threats under climate change. Though India is one among the leading countries in cotton production, the supply is not enough considering the increasing demand. Scientists across the Globe are indulged in developing new lines and cultures with capacity to produce more yields. In this context, here, we have made an attempt to study the growth, physiology, and yield traits of cotton culture - TCH 1819 before its release (now released in the name of CO 17) by different chemical treatments. Observation on the leaf gas exchange traits, leaf parenchymal cells distinguished the source sink relationship of the culture. Chemical manipulation by growth retardants reduced the gibberellins content and modified the foliage structure. By characterizing the physiological potential through manipulation by growth retardant (Mepiquat chloride (0.015 %)) increased the yield by 30%. The traits identified in this study are potential indicators in breeding programme before releasing the variety.

Seed discontinuous hydration does not benefit germination, but improves drought tolerance of Triplaris gardneriana seedlings

The discontinuous seed hydration enables the acquisition of tolerance to environmental stresses, causing a stress imprint. It may modify metabolic patterns and lead to improved stress responses. This study aims to evaluate the effects of discontinuous hydration on germination and on seedling growth of Triplaris gardneriana Wedd. under intermittent drought. The seeds have gone through cycles (0, 1, 2 and 3) of hydration and dehydration (HD). The seedlings produced were subjected to water deficit (daily watering and intervals of seven and fourteen days between watering). Seed germinability parameters and, relative growth rate (RGR) of seedling, leaf area, dry matter yield and leaf relative water content (RWC) were evaluated. The HD cycles did not benefit germination, but two HD cycles induced a better biomass accumulation and increased leaf area in seedlings under moderate water deficit, while three HD cycles promoted an increase in RGR and influenced the RWC values. Severe stress affects seedling growth, but subjection to HD cycles minimizes the deleterious effects of drought, suggesting discontinuous hydration acts leading stress imprint in plants.

Infuence of kaolin application on most important fruit and leaf characteristics of two apple cultivars under sustained defcit irrigation

BACKGROUND: Apple is one of the oldest and most valuable fruits. Water restriction is one of the major problems in the production of this fruit in some planting areas. METHODS: Effects of kaolin spray treatments were studied on two early apple cultivars of Golab and Shafi-Abadi under sustained deficit irrigation (SDI) in Alborz province, Iran during 2017 and 2018. Irrigation treatments were 100%, 85%, and 70% ETc and kaolin application were concentrations of 0, 3 and 6% in 2017 and 0, 1.5 and 3% in 2018. RESULTS: Results showed that 85% ETc treatment compared to other irrigation treatments improved apple tree crown volume in 2017. Deficit irrigation treatments significantly reduced fruit weight in both years. Application with 6% kaolin resulted in 33.3% increase in apple fruit weight compared to non-kaolin treatment at 100% ETc irrigation in the first year. Severe deficit irrigation (70% ETc) significantly reduced apple fruit length in both years, but 6% kaolin increased fruit length in both apple cultivars in 2017. Severe deficit irrigation treatment increased the firmness of apple fruit compared to control and mild deficit irrigation (85% ETc) in the first year of experiment. There was no significant difference between irrigation treatments for apple fruit firmness in the second year of experiment. Kaolin treatments of 1.5% and 3% at full irrigation increased the soluble solids content of apple fruit by 36.6% and 44.1% in 2018, respectively. Deficit irrigation treatments significantly increased leaf proline content compared to control in both years. In the first year, kaolin treatments increased leaf proline but in the second year, leaf proline was not significant. Deficit irrigation treatment of 70% ETc and 6% kaolin had the highest amount of glycine betaine content, malondialdehyde and hydrogen peroxide in apple leaf in the first year of experiment. CONCLUSIONS: Severe deficit irrigation stress (70% ETc) increased the activity of nonenzymatic defense systems of apple trees. Kaolin as a drought stress reducing agent can be recommended in apple orchards of Golab and Shafi-Abadi cultivars as an effective and inexpensive method to improve tolerance to drought stress conditions.

Advances in the physiological functions of plant lipids in response to stresses / 生物工程学报

Lipids are important components of living organisms that participate in and regulate a variety of life activities. Lipids in plants also play important physiological functions in response to a variety of abiotic stresses (e.g. salt stress, drought stress, temperature stress). However, most research on lipids focused on animal cells and medical fields, while the functions of lipids in plants were overlooked. With the rapid development of "omics" technologies and biotechnology, the lipidomics has received much attention in recent years because it can reveal the composition and function of lipids in a deep and comprehensive way. This review summarizes the recent advances in the functions and classification of lipids, the development of lipidomics technology, and the responses of plant lipids against drought stress, salt stress and temperature stress. In addition, challenges and prospects were proposed for future lipidomics research and further exploration of the physiological functions of lipids in plant stress resistance.

Effects of drought stress on physiological and biochemical and chemical components of Cinnamomum cassia seedlings / 中国中药杂志

Six month old Cinnamomum cassia seedlings were used to simulate drought stress with polyethylene glycol(PEG 6000). The physiological indicators(osmotic substances, antioxidant enzymes, etc.) and chemical components of seedlings under different drought levels and the correlation between the two were studied. The results showed that the chlorophyll content and relative water content decreased gradually with the increase of PGE 6000(0, 5%, 10%, 15%) concentration and time(3, 5, 7 d), while the soluble protein content, soluble sugar content and catalase(CAT) activity increased, but the rising rate slowed down with the time. The activities of peroxidase(POD), superoxide dismutase(SOD), malondialdehyde(MDA) and proline content increased at first and then decreased. The content of coumarin, cinnamaldehyde, cinnamic acid and dimethoxycinnamaldehyde decreased, while the content of cinnamyl alcohol continued to increase.Under drought stress, the fluorescence signals of reactive oxygen species and no contents in roots of C. cassia seedlings were significantly stronger than those of the control.Further correlation analysis showed that coumarin content, di-methoxycinnamaldehyde content and osmoregulation substance content were significantly negatively correlated(P<0.05), cinnamic acid content was significantly negatively correlated with POD and SOD activities(P<0.01).It was found that C. cassia seedlings showed a certain degree of drought tolerance under short-term or mild drought stress, but if the drought exceeded a certain degree, the physiological metabolism of the seedlings would be unbalanced.

Effect of EBR on Seed Germination， Seedling Growth and Key Enzyme Activities for Flavonoid Biosynthesis in Astragalus membranaceus var. mongholicus Under PEG-induced Drought Stress / 中国实验方剂学杂志

Objective:To study the effects of 24-epibrassinolide （EBR） at different concentrations on seed germination， seedling growth and key enzyme activities for flavonoid biosynthesis in <italic>Astragalus membranaceus </italic>var.<italic> mongholicus</italic> under polyethylene glycol （PEG）-induced drought stress， in order to provide theoretical reference for standardizing the drought-resistant cultivation techniques of <italic>A. membranaceus </italic>var.<italic> mongholicus</italic>. Method:The seeds of <italic>A. membranaceus </italic>var.<italic> mongholicus </italic>were soaked in EBR solution at different concentrations（0.001， 0.01， 0.1， 1， 10 μmol·L^-1） followed by foliar spraying to explore their effects on seed germination， seedling growth， photosynthesis， chlorophyll and malondialdehyde （MDA） contents， and key enzyme activities for flavonoid biosynthesis under drought stress induced by 20% polyethylene glycol （PEG）-6000. Result:Compared with the control（CK）group， PEG-induced drought stress led to an obvious decrease in germination potential， germination rate， germination index， vigor index， relative germination rate， plant height， root length， aboveground and root dry weight， net photosynthetic rate （<italic>Pn</italic>）， stomata conductance （<italic>Gs</italic>）<italic>， </italic>transpiration rate （<italic>Tr</italic>）， chlorophyll contents and chlorophyll a/b ratio， while a significant increase in intercellular carbon dioxide concentration （<italic>Gi</italic>）， MDA， flavonoids contents， and key enzyme activities for flavonoid biosynthesis such as phenylalanine ammonia lyase （PAL）. The treatment with exogenous EBR solution at the suitable concentration significantly enhanced the adaptation of <italic>A. membranaceus </italic>var.<italic> mongholicus </italic>seeds and seedlings to PEG-induced drought stress， manifested as significantly elevated germination potential， germination rate， germination index， vigor index， relative germination rate， plant height， root length， aboveground and root dry weight， <italic>Pn</italic>， <italic>Gs， Tr</italic>， chlorophyll a/b ratio， chlorophyll and flavonoids contents and key enzyme activities for flavonoid biosynthesis like PAL while lowered <italic>Ci</italic> and MDA contents. The optimal concentration of EBR solution was 0.1 μmol·L^-1. Conclusion:Exogenous EBR solution at the suitable concentration ameliorates the inhibitory effect of 20% PEG stress against seed germination and seedling growth of <italic>A. membranaceus </italic>var.<italic> mongholicus</italic>， reduces the oxidative damage in leaves， and improves the stress resistance to a certain extent by up-regulating the key enzyme activities and promoting flavonoid synthesis.

Metabolomics Analysis of Codonopsis pilosula Under Drought Stress Based on LC-MS / 中国实验方剂学杂志

Objective:The biological mechanism of <italic>Codonopsis pilosula</italic> adaptation to drought was explored by determining the root metabolome of <italic>C. pilosula</italic> during harvesting. Method:Non-targeted metabonomics LC-MS was used to screen differential metabolites by multivariate statistical analysis，univariate statistical analysis and metabolic pathway enrichment analysis. Result:①There were 274 metabolites in LD vs CK group，142 of which were up-regulated and 132 of which were down-regulated. There were 284 metabolites with significant difference in MD vs CK group，of which 157 were up-regulated and 127 were down-regulated. There were 317 metabolites with significant difference in SD vs CK group，of which 133 were up-regulated and 184 were down-regulated. ②Differential metabolites were annotated into kyoto Encyclopedia of Gene and Genomes （KEGG） database and 82 differential metabolic pathways were obtained，among which sphingolipids metabolism was significantly enriched （<italic>P</italic><0.01）.Metabolism of arginine and proline，tryptophan，alanine，galactose，nicotinic acid and nicotinamide，cysteine and methionine，arachidonic acid，linolenic acid and glycerides were significantly enriched in different metabolite pathways （<italic>P</italic><0.05）. ③The metabolites of the three comparison groups before and after enrichment were classified and analyzed. It was found that they were mainly concentrated in fatty acyls group，carboxylic acid and derivatives，and organ oxygen compounds，followed by sphingolipids，indoles and derivatives，organonitrogen compounds，glycerophospholipids，pyridines and derivatives，peptidomimetics，glycerolipids and so on.In the drought stress of <italic>C. codonopsis</italic>，carbohydrate related metabolites were mainly up-regulated，lipid related metabolites were mainly down-regulated，and all other metabolites were up-regulated. Conclusion:The changes of metabolites in the roots of <italic>C. pilosula</italic> under drought stress were elucidated. carbohydrate and lipid-related metabolites were the main products of <italic>C. pilosula</italic> under drought stress，and these metabolites may be the main reason to improve the ability of <italic>C. pilosula</italic> to resist drought，which laid a foundation for further study on the mechanism of <italic>C. pilosula</italic> to resist drought.

Effect of Drought Stress on Growth and Photosynthetic Physiological Parameters of Acanthopanax senticosus / 中国实验方剂学杂志

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.

Influence of Climate on Oak Savanna Tree Species in the Midwestern United States

Aims: The previously abundant high quality and open canopy oak savanna communities in the Midwest have been reduced by more than 98% of their pre-settlement (pre-1840) area because of changing land use and represent some of the most threatened ecosystems in North America. Prior knowledge of oak savanna communities’ climatic resilience to potential impact of climate change and competition is critical to restoration success. This study examined sensitivity to climatic stress, and effects of competition, which are important considerations during oak savanna restoration. Methodology: Dendrochronological methods were used to sample oak savanna communities located in MacCready Reserve (MR) situated in southern Michigan, U.S.A. The influence of climate (mainly temperature and precipitation) on white oak (Quercus alba L.), red maple (Acer rubrum L), and black cherry (Prunus serotina Ehrh) were correlated using dendroclimatic techniques. The effect of competitor species (A. rubrum and P. serotina) on Q. alba were examined using competitor ratio chronologies and examining correlations with climatic variables. Results: Findings indicate that precipitation in winter, spring, and summer is beneficial for radial growth of white oak. White oak is more resilient to drought stress than red maple and black cherry due to its ecophysiological adaptations but tends to grow rather slower when in competition with shade tolerant and fire sensitive competitor species. Conclusion: Overall, this study has shown that temperature and precipitation play key roles in tree productivity and thus climatic sensitivity should be incorporated in the restoration of oak savanna ecosystems.

Physiological and Biochemical Changes under Salinity and Drought Stress in Ricebean [Vigna umbellata (Thunb.) Ohwi and Ohashi] Seedlings

Aims: To study the effect of iso-osmotic potentials of drought and salinity during seedling growth stage in ricebean. Study Design: Completely randomised design. Place and Duration of Study: The lab experiment was conducted during the year of 2017- 2018 and 2018-2019 in ricebean variety Bidhan 1 at Department of Plant Physiology, Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West Bengal, India. Methodology: For studying the effect of iso-osmotic potential of salinity and drought stress, the solutions of NaCl and PEG 6000 with -0.2, -0.4 and -0.8 MPa osmotic potential were used and the experiment was conducted in sand culture using modified Hoagland solution [1] under laboratory condition of diffused light, at around 80±1% relative humidity (R.H.) and at a temperature of 28±1°C. Results: All the biochemical parameters under study, in general were adversely affected by the both stress with the effects being more drastic as the intensity of stress increased. The highest intensity of salinity stress was found to produce more adverse effects than drought in respect of RLWC, leaf chlorophyll as well as protein content in leaves of ricebean in the present experiment. While the content of soluble sugar, starch and phenol in the leaf were more drastically affected by drought stress. Conclusion: The drought stress was found to register more drastic effects on seedling growth as compared to iso-osmotic potential of salinity stress, especially, at the highest intensity of stress in ricebean cultivar Bidhan 1.

Contrasting the expression pattern change of polyamine oxidase genes and photosynthetic efficiency of maize (Zea mays L.) genotypes under drought stress

The aim of this study was to contrast the effects of drought stress on polyamine oxidases gene expression andactivity as well as photosynthetic efficiency in relatively tolerant (Karoon) and sensitive (260) maize genotype.d Reduction in leaf relative water content as a result of drought led to increase in root growth, butdiminished shoot growth indices. Under drought stress, activity of antioxidant enzyme, catalase, significantlyincreased in both genotypes, whereas significant higher activity of superoxide dismutase and peroxidase wasonly observed in Karoon genotype. Expression of polyamine oxidase (PAO) genes (zmPAO1, zmPAO2,zmPAO3, zmPAO4, zmPAO5, zmPAO6) and activity of enzymatic polyamine oxidation was increased in bothgenotypes under drought stress. The enhancement in PAO gene expression and enzyme activity was moreprominent in Karoon cultivar compared to 260. Chlorophyll a fluorescence and fast induction kinetics werenegatively influenced by drought stress. These parameters were more affected in 260 cultivar compared withKaroon. Our results suggest that under drought stress, higher activity of polyamine oxidase pathway in backconversion of Spermine and spermidine to putrescine (protectant of photosynthetic apparatus) as well as higherantioxidant enzymes activity in Karoon cultivar, may play a role in higher efficiency of photosynthetic processin this cultivar

Seed germination and antioxidant enzyme activity in seedlings of diploid and tetraploid bahiagrass under water restriction / Germinação de sementes e atividade de enzimas antioxidantes em plântulas de grama forquilha diplóide e tetraploide sob restrição hídrica

ABSTRACT: The objective of the following research was to investigate the physiological responses of two bahiagrass genotypes (Paspalum notatum Flügge) submitted to water restriction, induced by polyethylene glycol (PEG6000), during seed germination. Seeds of cv. Pensacola (diploid) and Bagual ecotype (tetraploid) were placed on paper moistened with osmotic solutions at potentials of 0.0; -0.1; -0.2 and -0.3 MPa. Composed of two subsamples of 100 seeds and four experimental units per treatment, the germination test was conducted in a germination chamber under alternating temperatures of 30 °C (8 hours) and 20 °C (16 hours), with presence of light during the higher temperature. Final germination percentage and germination speed index of the seeds, as well as early growth, activity and expression of antioxidant enzymes of seedlings were evaluated. The water restriction induced by PEG6000 reduced the percentage of germination in Pensacola (from 74% to 59%) and Bagual (34% to 10%). For the latter, the evaluation of seedlings showed higher dry mass in relation to cv. Pensacola (1.7 times higher in root and 1.6 times in shoot). In response to moderate water restriction, the genotypes showed increases in root growth (1.7 times higher in -0.1 compared to 0.0 MPa), both in expression and enzymatic activity (superoxide dismutase and catalase).

RESUMO: O presente estudo objetivou avaliar as respostas fisiológicas de dois genótipos de grama forquilha (Paspalum notatum Flügge) sob restrição hídrica induzida por polietileno glicol (PEG6000) durante a germinação de sementes. Sementes da cv. Pensacola (diplóide) e do ecótipo Bagual (tetraplóide) foram colocadas em papel umedecido com soluções osmóticas nos potenciais de 0,0; -0,1; -0,2 e -0,3 MPa. Composto de duas subamostras de 100 sementes e quatro unidades experimentais por tratamento, o teste de germinação foi conduzido em câmara de germinação sob temperatura alternada de 30-20 ºC, com presença de luz durante a maior temperatura. Foram avaliados a porcentagem final e o índice de velocidade de germinação das sementes, assim como o crescimento inicial, a atividade e a expressão de enzimas antioxidantes das plântulas. A restrição hídrica induzida por PEG6000 reduziu o percentual de germinação em Pensacola (de 74 para 59%) e Bagual (34 para 10%). Este último, na avaliação de plântulas, apresentou massa seca superior em relação à cv. Pensacola (1.7 vezes superior em raiz e 1.6 vezes superior em parte aérea). Em resposta à restrição hídrica moderada, os genótipos apresentaram aumentos tanto do crescimento radicular (1.7 vezes superior em -0.1 em comparação com 0.0 MPa), quanto da expressão e da atividade enzimática (superóxido dismutase e catalase).

Effect of stress on the leaf anatomy of sugarcane cultivars with different drought tolerance(Saccharum officinarum, Poaceae)

Introduction: Drought is an important stress factor for sugarcane production in many areas of the world. Water proportion and moisture indices are applicable information for agronomic planning to forecast water excess or deficit during the crop cycle. Objective: Leaf anatomical features of two different sugarcane Saccharum 'UT12' (drought susceptible cultivar) and Saccharum 'UT13' (drought tolerant cultivar) were compared under early drought stress situation between 30 and 90 days after planting. Methods: Forty leaf anatomical features were investigated using peeling and free hand sectioning technique. Results: Some anatomical characteristics showed response to drought stress. Saccharum 'UT12' demonstrated higher sensitivity toward anatomical characteristics than Saccharum 'UT13'. A total of 23 and 15 out of the 40 anatomical characteristics showed significance in Saccharum 'UT12' and Saccharum 'UT13', respectively. Some anatomical features such as cell wall and cuticle thickness, vascular bundle size, stomatal size and density can be used as important markers for drought stress assessment in sugarcane leaf. Conclusions: This is the first report describing comparative leaf anatomy of sugarcane Saccharum 'UT12' and Saccharum 'UT13' in Thailand under drought stress. Results will provide important information to improve adaptation mechanisms of tolerant sugarcane cultivars under initial drought stress situations.

Introducción: La sequía es un factor de estrés importante para la producción de caña de azúcar en muchas áreas del mundo. La proporción de agua y los índices de humedad son información aplicable en la planificación agronómica para pronosticar el exceso o el déficit de agua durante el ciclo del cultivo. Objetivo: Se compararon las características anatómicas de las hojas de dos cañas de azúcar diferentes Saccharum 'UT12' (cultivar susceptible a la sequía) y Saccharum 'UT13' (cultivar tolerante a la sequía) bajo una situación de estrés por sequía temprana entre 30 y 90 días después de la siembra. Métodos: Se investigaron las características anatómicas de cuarenta hojas utilizando la técnica de seccionamiento de pelado y manos libres. Resultados: Algunas características anatómicas mostraron respuesta a estrés por sequía. Saccharum "UT12" demostró una mayor sensibilidad hacia las características anatómicas que Saccharum 'UT13'. Un total de 23 y 15 de las 40 características anatómicas mostraron significancia en Saccharum 'UT12' y Saccharum 'UT13', respectivamente. Algunas características anatómicas como la pared celular y el grosor de la cutícula, el tamaño del haz vascular, el tamaño y la densidad de los estomas se pueden utilizar como marcadores importantes para evaluar el estrés por sequía en la hoja de caña de azúcar. Conclusiones: Este es el primer reporte que describe la anatomía comparada de la hoja de la caña de azúcar Saccharum 'UT12' y Saccharum 'UT13' en Tailandia bajo estrés por sequía. Los resultados proporcionarán información importante para mejorar los mecanismos de adaptación de cultivares tolerantes de caña de azúcar bajo situaciones iniciales de estrés por sequía.

Sequencing and analysis of transcriptome to reveal regulation of gene expression in Salvia miltiorrhiza under moderate drought stress / 中草药

Objective: To analyze the molecular mechanism of different tissues of Salvia miltiorrhiza in response to moderate drought stress by transcriptome sequencing. Methods: The roots and leaves of 4-month-old S. miltiorrhiza from moderate drought stressed group and control group (the relative water content in soil was 55%-60% and 75%-80%, respectively) were used as the test material. And the transcriptome sequencing analysis was carried out by using Illumina HiSeq 2000. After obtaining transcriptome data, gene function annotation, differentially expressed genes (DEGs) screening and and co-expression network analysis were performed. Results: A total of 58 085 Unigenes were obtained by transcriptome sequencing. Among them, 28 846 Unigenes were annotated, and there were 1 853 and 1 457 DEGs in roots and leaves, respectively. The GO enrichment results showed that the DEGs of the roots and leaves were both significantly enriched in metabolic process, stimulus response, cell structure, and catalytic activity, etc. The KEGG pathway analysis showed that DEGs in roots were significantly enriched in DNA replication, plant hormone signal transduction, plant-pathogen interaction, and carotenoid biosynthesis, etc. And the DEGs in leaves were mainly concentrated in amino acids, alkaloids, and phenylpropanoid biosynthesis. The genes of key enzymes involved in phenylpropanoid and terpenoid biosynthesis were up-regulated by moderate drought stress, which might be the basis for accelerating the accumulation of active ingredients in leaves and roots of S. miltiorrhiza. AP2 /ERF, bHLH, bZIP, WRKY, and MYB transcription factors were significantly differentially expressed in roots and leaves. Gene co-expression network analysis predicted transcription factors that may be involved in regulating the expression of terpenoid genes under moderate drought stress. Conclusion: The high-throughput transcriptome sequencing revealed the regulatory characteristics of moderate drought stress on gene expression in different tissues of S. miltiorrhiza, which could provide scientific basis for further research on the biosynthesis mechanism of medicinal components of S. miltiorrhiza and reasonable irrigation in cultivation.

Transcriptome analysis of stems of Pinellia ternata under drought stress simulated by PEG / 中草药

Objective: In this study, the transcriptome profile of the stems from Pinellia ternata treated by 30% polyethylene glycol simulated drought stress was analyzed, the key enzyme genes responded to the drought stress were explored, so as to explore the molecular mechanism of P. ternata sprout tumble responded to the drought stress. Methods: The stem segments of P. ternata under drought stress were used as research materials. The Illumina Hiseq 2500 platform was applied for transcriptome sequencing, and bioinformatics analysis was performed on the transcriptome data. Results: A total of 23.00 Gb clean data was obtained, 37 467 952 and 39 903 362 clean reads were gained from the control groups and the drought stress treatment, respectively, and 100 274 uingenes were assembled by Trinity software. A total of 41 132 unigenes were finally obtained with functional annotations against the Nr, eggNOG, Pfam, Swiss-Prot, KOG, GO, KEGG, and COG databases. Furthermore, 4 052 differentially expressed genes (DEGs) were obtained, in details, 2 080 DEGs were up-regulated while 1 972 DEGs were with down-regulated expression. KEGG Pathway enrichment analysis showed that DEGs were mostly involved in ribosome, carbon metabolism, starch and sucrose metabolism, plant hormone signal transduction and biosynthesis of amino acids process. The expression levels of the genes encoded plant hormone metabolism and signal transduction, redox-related enzymes, heat shock proteins and vacuolar processing enzymes were significantly promoted after drought stress treatment, while most of the DEGs encoded aquaporins were down-regulated. Conclusion: By analyzing the transcriptome profiles of P. ternata under drought stress simulated by PEG, the candidate genes associated with water metabolism, plant hormone and signal transduction, as well as the related responsive proteins were obtained, which could provide abundant genetic resources and theoretical basis for understanding the mechanism of P. ternata sprout tumble caused by drought stress.

Role of growth regulators and plant water extracts on the productivity and water use efficiency of wheat genotypes under limited water supply / Papel dos reguladores de crescimento e dos extratos de plantas sobre a eficiência da produtividade e do uso da água dos genótipos de trigo sob abastecimento de água limitada

Empowerment of wheat genotypes by application of growth regulators, compatible solutes and plant extracts under water restriction is an important strategy for getting sustainable yield. This study aimed to evaluate the effects of drought stress on the growth and yield of wheat genotypes and also monitor and compare the role of ABA, SA as well as moringa and mulbery leaf water extracts in improving drought tolerance of wheat genotypes. The work was performed at the research area of the Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan, Pakistan. Three wheat cultivars Aas-2011, Faisalabad- 2008 and Triple dwarf-1 were subjected to drought stress (skipping the irrigation at grain filling stage). The wheat genotypes were subjected to treatments viz., T1 i.e. All normal irrigation without application of abscisic acid (ABA), salicylic acid (SA), moringa (MLE) and mulberry leaf water extract (MBLE), T2 i.e. skipping the irrigation at grain filling stage and application of 2µM ABA, T3 i.e. skipping the irrigation at grain filling stage and application of 10 m mol SA, T4 i.e. skipping the irrigation at grain filling stage and application of 15% MLE and T5 i.e. skipping the irrigation at grain filling stage and application of 10% MBLE. The experiment was laid out in Randomized Complete Block Design with factorial arrangement and repeated three times. From this study it is concluded that Aas-2011 shown best result under drought condition by applying growth regulators and plant water extracts.

O fortalecimento de genótipos de trigo pela aplicação de reguladores de crescimento, solutos compatíveis e extratos vegetais sob restrição hídrica é uma importante estratégia para obtenção de produção sustentável. Trilha de campo foi realizada na área de pesquisa da Faculdade de Ciências Agrárias, Universidade de Ghazi, Dera Ghazi Khan, Paquistão. Três cultivares de trigo Aas-2011, Faisalabad-2008 e Triple anão-1 foram submetidas a estresse hídrico (pulando a irrigação no estágio de enchimento de grãos). Os genótipos de trigo foram submetidos a tratamentos, T1, ou seja, irrigação normal sem aplicação de ácido abscísico (ABA), ácido salicílico (SA), moringa (MLE) e extrato de água de amoreira (MBLE), T2¬, pular a irrigação em estágio de enchimento de grãos e aplicação de ABA 2µM, T3 ou seja, ignorando a irrigação no estágio de enchimento de grãos e aplicação de 10 m mol SA, T4 ou seja, ignorando a irrigação no estágio de enchimento de grãos e aplicação de 15% MLE e T5 ou seja, ignorando a irrigação no enchimento de grãos estágio e aplicação de 10% MBLE. O experimento foi exposto no delineamento de blocos completos casualizados com arranjo fatorial e repetido três vezes. A partir deste estudo conclui-se que Aas-2011 apresentou melhor resultado sob condição de seca, aplicando reguladores de crescimento e extratos de água de plantas.

Development of a drought stress-resistant rice restorer line through Oryza sativa–rufipogon hybridization

Restorer line F6 (Oryza sativa L. ssp. indica) has been widely used in hybrid rice breeding systems in southern China. However, line F6 is susceptible to drought stress, which restricts its utilization in many areas. Dongxiang wild rice (DXWR, Oryza rufipogon Griff.) has strong drought stress resistance, but the molecular factors responsible for drought resistance in DXWR remain unknown. In this study, we used the combination of phenotypic selection and molecular marker-assisted selection (MAS) to improve the drought stress resistance of line F6 by introgression of qSDT12-2, a large effect drought stress-related quantitative trait locus identified in DXWR. Molecular MAS was carried out using linked marker RM1226, which is associated with qSDT12-2. Genomic background assessmentwas performed using 112 polymorphic markers. Finally, a stable drought stress-resistant backcross inbred line (BIL) was developed from a BC5F5 population, termed BIL627. Genetic constitution analysis revealed that the genome of BIL627 is almost identical (99.1%) to that of the restorer line F6. Further, BIL627 showed no yield penalty and no decrease in restorationability under normal conditions. Taken together, our findings reveal the intrinsic value of using genetic resources present in wild species of Oryza to improve undesirable traits found in cultivated rice.

Improvements in biomass production: Learning lessons from the bioenergy plants maize and sorghum

The use of biomass energy is preferred over fossil fuels as the former is more sustainable and emits a reduced amount of greenhouse gases. Sorghum, a tropical C4 plant, is known to have a marked drought tolerance. However, very little is known about the mechanisms involved. An allied species Zea mays, also a C4 plant, is far less drought tolerant. Both plants are known to accumulate high biomass during the course of their growth cycle and can be used as renewable energy sources. This article discusses the possibilities of using these two plants for the production of improved biomass in the context of drought tolerance and sustainable food production. Crucial and novel approaches that render Sorghum more tolerant to drought have been reviewed. Novel drought tolerance mechanisms in two sorghum cultivars- Samsorg 17 (more drought tolerant) and Samsorg 40 (less drought tolerant) have also been reviewed.