Variation between and within species of rapeseed (Brassica campestris and B. napus) in response to drought stress. I. Sensitivity at different stages of development

1978 ◽  
Vol 29 (3) ◽  
pp. 469 ◽  
Author(s):  
RA Richards ◽  
N Thurling
Keyword(s):  
Drought Stress ◽  
Seed Yield ◽  
Brassica Campestris ◽  
Stem Elongation ◽  
Principal Component ◽  
Plant Size ◽  
Root Weight ◽  
Drought Treatment ◽  
Plant Weight ◽  
Major Factors

Drought imposed at different times on four spring cultivars of each of two oilseed rape species (Brassica campestris and B. napus) markedly influenced seed yield and its components and other characteristics of the mature plant. In general, drought reduced those plant and yield components associated with plant size, whereas other characters were variable, depending on the species and treatments. Seed yield was lowest in both species when drought was applied either from stem elongation or from the time of anthesis. However, considering grain yields in terms of the amount of water added in each treatment, B. napus cultivars were most sensitive at anthesis, with the exception of Masoweicki which was most sensitive at pod-filling. In B. campestris, Span was most sensitive when drought stress was first imposed at stem elongation, whilst other cultivars were sensitive at later reproductive stages. Principal component analyses reduced the complex interrelationships between all variables excluding yield to two major factors in each species and treatment. In general, the first factor, which explained most of the variation in the parameters measured, was composed of variables associated with plant size, whereas the second was composed of variables which were independent of plant size. The relative importance of these two factors as yield determinants varied substantially with the different species and treatments. In B. napus the first factor was the major determinant of yield ill the control and in the drought treatment imposed from stem elongation. In B. campestris the second factor was a significant determinant of yield in all treatments and the major factor influencing yield in the control and stem elongation treatments. Increased root weight was associated with increased yield in the drought treatments in both species, but this was primarily due to its association with plant size. When the influence of plant size was accounted for, it was observed that a smaller root weight relative to the above-ground plant weight and a greater tap-root weight relative to lateral root weight was associated with higher yield in both species in all drought treatments. As well as these latter characters, seed weight per pod, and harvest index were the most important group of characters contributing to yield in both species in all treatments when variation in plant size was accounted for.

scholarly journals CHANGES IN FRUIT YIELD AND PHOTOSYNTHESIS PARAMETERS IN DIFFERENT OLIVE CULTIVARS (Olea europaea L.) UNDER CON-TRASTING WATER REGIMES

2020 ◽  
Vol 19 (3) ◽  
pp. 135-147
Author(s):  
Majid Golmohammadi ◽  
Omid Sofalian ◽  
Mehdi Taheri ◽  
Alireza Ghanbari ◽  
Valiollah Rasoli
Keyword(s):  
Drought Stress ◽  
Olea Europaea ◽  
Principal Component ◽  
Fruit Yield ◽  
Photosynthetic Parameters ◽  
Olive Cultivar ◽  
Drought Treatment ◽  
Olea Europaea L ◽  
Olive Cultivars ◽  
Olea Europaéa

The evergreen tree olive (Olea europaea L.) is the only species of the genus Olea that produces edible fruits with high ecological and economic value. This tree species has developed a series of physiochemical mechanisms to tolerate drought stress and grow under adverse climatic environments. One of these mechanisms is photosynthesis activities, so that as yet little information achieved about the relations between olive production and photosynthetic parameters under drought conditions. An experiment was carried out during two consecutive years (2015–2017) to study the response of 20 different olive tree cultivars (Olea europaea L.) to drought stress. Several parameters like net photosynthetic rate (PN), stomatal conductance (GS), transpiration rate (TE), photosynthetic pigments (total chlorophyll, chlorophyll a, b and carotenoid) and fruit yield were measured. The results of combined analysis of variance for fruit yield and other measured traits showed that year, drought treatment, cultivar main effects and their interactions were highly significant. The results indicated that drought stress reduced all traits, however GS (42.80%), PN (37.21%) and TE (37.17%) significantly affected by drought. Lower reduction in photosynthetic performance (PN, GS and TE) in the cultivar T7 compared to other olive cultivars allowed them to maintain better fruit yield. Principal component analysis (PCA) identified two PCs that accounted for 82.04 and 83.27% of the total variation in photosynthetic parameters under optimal and drought stress conditions, respectively. Taken together, mean comparison, relative changes due to drought and biplot analysis revealed that cultivars ‘T7’, ‘Roghani’, ‘Koroneiki’, ‘Korfolia’ and ‘Abou-satl’ displayed better response against drought stress. According to our results, one olive cultivar namely ‘T7’, could be used in olive breeding programs to improve new high yielding cultivars with drought tolerance for use in the drought-prone environments.

scholarly journals Growth and Comprehensive Quality Index of Tomato under Rain Shelters in Response to Different Irrigation and Drainage Treatments

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Guang-cheng Shao ◽  
Ming-hui Wang ◽  
Na Liu ◽  
Min Yuan ◽  
Prem Kumar ◽  
...  
Keyword(s):  
Fruit Quality ◽  
Quality Index ◽  
Soluble Sugar ◽  
Principal Component ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Root Weight ◽  
Drought Treatment ◽  
Soil Desiccation ◽  
Underground Pipe

The effects of two levels of irrigation water (100%, 60%) and buried underground pipe depths (0.8 m, 0.6 m) under rain shelters’ conditions on yield and some quality parameters of tomato were investigated. A fully randomized factorial experiment was conducted between April and August in 2011 and 2012 at Hohai University. It was found that drainage treatments enhanced biomass production, whereas soil desiccation led to biomass reduction. At 60 cm buried underground pipe depths, the drought treatments increased the mean root weight and root-shoot ratio by 14% and 39%, respectively. The main effects of drainage treatments on the fruit quality were increases in total soluble solids (TSS), soluble sugar (SS), and vitamin C (VC) compared to the control. In addition, drainage treatments increased the average yield by 13% and 9%, respectively, in both years. The drought treatments did not significantly alter fruit yield, although mean single fruit weight was slightly reduced. Instead, these treatments tend to have great potential to improve fruit quality (TSS, SS, and VC) to variable extents. In both years, the drought treatment at 60 cm buried underground pipe depths proved to possess the highest comprehensive quality index based on Principal Component Analysis.

scholarly journals Enzymatic Activities and Gene Transcript Levels Associated with the Augmentation of Antioxidant Constituents during Drought Stress in Lettuce

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 444
Author(s):  
Ryohei Koyama ◽  
Aika Yoshimoto ◽  
Misaki Ishibashi ◽  
Hiromichi Itoh ◽  
Yuichi Uno
Keyword(s):  
Drought Stress ◽  
Radical Scavenging ◽  
Gene Transcript ◽  
Rna Seq ◽  
Drought Treatment ◽  
Plant Constituents ◽  
Major Factors ◽  
Upregulated Genes ◽  
Dehydrin Gene ◽  
Moderate Stress

Efficient cultivation methods were investigated to promote the branding of products in plant factories. Moderate stress can enhance plant constituents that are beneficial for human health, without reducing yield. Dehydration stress in lettuce rhizospheres increased some antioxidants, including L-ascorbic acid (AsA) and polyphenols. In this study, the major factors contributing to the augmentation of antioxidant constituents were investigated. The drought treatment resulted in increased hydrophilic oxygen radical absorbance capacity (ORAC) values but not hydrophobic ORAC values. Both activities of antioxidant enzymes (superoxide dismutase, SOD, and ascorbate peroxidase, APX) were elevated under drought conditions. RNA-seq analysis revealed 33 upregulated and 115 downregulated differentially expressed genes, and 40 gene ontology enrichment categories. A dehydrin gene was the most significant among the upregulated genes in response to drought stress. Dehydrin protects plant cells from dryness through multiple functions, such as radical scavenging and protection of enzymes. Real-time PCR validated the substantial increase in some dehydrin paralogs with root desiccation. In conclusion, the enhancement of antioxidant levels by drought stress is likely not due to the induction of antioxidant enzyme genes, but due to increased enzymic activities. These activities might be protected by dehydrins encoded by the upregulated paralogs under drought stress.

scholarly journals Flavonoids improve drought tolerance of maize seedlings by regulating the homeostasis of reactive oxygen species

2021 ◽  
Author(s):  
Baozhu Li ◽  
Ruonan Fan ◽  
Guiling Sun ◽  
Ting Sun ◽  
Yanting Fan ◽  
...  
Keyword(s):  
Free Radicals ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Infrared Imaging ◽  
Oxygen Free Radicals ◽  
Transcriptome Profiling ◽  
Far Infrared ◽  
Drought Treatment ◽  
Physiological Characterization ◽  
Oxidative Damages

Abstract Background and aims As drought threatens the yield and quality of maize (Zea mays L.), it is important to dissect the molecular basis of maize drought tolerance. Flavonoids, participate in the scavenging of oxygen free radicals and alleviate stress-induced oxidative damages. This study aims to dissect the function of flavonoids in the improvement of maize drought tolerance. Methods Using far-infrared imaging screening, we previously isolated a drought overly insensitivity (doi) mutant from an ethyl methanesulfonate (EMS)-mutagenized maize library and designated it as doi57. In this study, we performed a physiological characterization and transcriptome profiling of doi57 in comparison to corresponding wild-type B73 under drought stress. Results Under drought stress, doi57 seedlings displayed lower leaf-surface temperature (LST), faster water loss, and better performance in growth than B73. Transcriptome analysis reveals that key genes involved in flavonoid biosynthesis are enriched among differentially expressed genes in doi57. In line with these results, more flavonols and less hydrogen peroxide (H2O2) were accumulated in guard cells of doi57 than in those of B73 with the decrease of soil water content (SWC). Moreover, the capacity determined from doi57 seedling extracts to scavenge oxygen free radicals was more effective than that of B73 under the drought treatment. Additionally, doi57 seedlings had higher photosynthetic rates, stomatal conductance, transpiration rates, and water use efficiency than B73 exposed to drought stress, resulting in high biomass and greater root/shoot ratios in doi57 mutant plants. Conclusion Flavonoids may facilitate maize seedling drought tolerance by lowering drought-induced oxidative damage as well regulating stomatal movement.

scholarly journals Comparing transcriptional responses to Fusarium crown rot in wheat and barley identified an important relationship between disease resistance and drought tolerance

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Z. Y. Su ◽  
J. J. Powell ◽  
S. Gao ◽  
M. Zhou ◽  
C. Liu
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Crown Rot ◽  
Differentially Expressed ◽  
Transcriptional Responses ◽  
Drought Treatment ◽  
Crop Species ◽  
Fusarium Crown Rot ◽  
Important Relationship ◽  
The Impact

Abstract Background Fusarium crown rot (FCR) is a chronic disease in cereal production worldwide. The impact of this disease is highly environmentally dependant and significant yield losses occur mainly in drought-affected crops. Results In the study reported here, we evaluated possible relationships between genes conferring FCR resistance and drought tolerance using two approaches. The first approach studied FCR induced differentially expressed genes (DEGs) targeting two barley and one wheat loci against a panel of genes curated from the literature based on known functions in drought tolerance. Of the 149 curated genes, 61.0% were responsive to FCR infection across the three loci. The second approach was a comparison of the global DEGs induced by FCR infection with the global transcriptomic responses under drought in wheat. This analysis found that approximately 48.0% of the DEGs detected one week following drought treatment and 74.4% of the DEGs detected three weeks following drought treatment were also differentially expressed between the susceptible and resistant isolines under FCR infection at one or more timepoints. As for the results from the first approach, the vast majority of common DEGs were downregulated under drought and expressed more highly in the resistant isoline than the sensitive isoline under FCR infection. Conclusions Results from this study suggest that the resistant isoline in wheat was experiencing less drought stress, which could contribute to the stronger defence response than the sensitive isoline. However, most of the genes induced by drought stress in barley were more highly expressed in the susceptible isolines than the resistant isolines under infection, indicating that genes conferring drought tolerance and FCR resistance may interact differently between these two crop species. Nevertheless, the strong relationship between FCR resistance and drought responsiveness provides further evidence indicating the possibility to enhance FCR resistance by manipulating genes conferring drought tolerance.

Defoliation frequency and cultivar effects on the storage and utilisation of stolon and root reserves in white clover

2000 ◽  
Vol 51 (8) ◽  
pp. 1039 ◽  
Author(s):  
A. R. Lawson ◽  
K. B. Kelly ◽  
P. W. G. Sale
Keyword(s):  
White Clover ◽  
Plant Size ◽  
Water Soluble ◽  
Cultivar Differences ◽  
Soluble Carbohydrate ◽  
Leaf Production ◽  
Plant Weight ◽  
Stolon Length ◽  
Defoliation Frequency ◽  
Leaf Appearance

The effects of defoliation frequency (2 or 6 defoliations over a 91-day period) on the reserve status and growth rate of 2 white clover cultivars, cvv. Irrigation (medium-leafed) and Haifa (large-leafed), were examined over the final 42 days of the defoliation treatments. The clover plants consisted of single stolons growing in a sand/scoria mix in an unheated glasshouse, and were fertilised weekly with a solution containing essential nutrients excluding nitrogen. More frequent defoliation reduced the leaf appearance rate, stolon elongation rate, and plant size, and increased stolon death, with all of these effects being less pronounced in Irrigation than in Haifa (18% v. 30%, 60% v. 80%, and 23% v 34%, respectively, for leaf appearance rates, stolon elongation rates, and the proportion of stolon length that died). With infrequent defoliation, the combined utilisation of starch and water-soluble carbohydrate (WSC) reserves in the first 14 days after defoliation was equivalent to 15% of the plant weight at defoliation, and to 95% of the new leaf produced during that period. Frequent defoliation reduced the reserve content and remobilisation less in Irrigation than in Haifa, with the combined mass of remobilised starch and WSC over the first 14 days after defoliation being 2.9% and 2.0% of the plant weight at defoliation, and 29% and 19% of leaf production over that period, for Irrigation and Haifa, respectively. The greater reserve mobilisation in Irrigation than in Haifa plants under frequent defoliation probably contributed to their higher growth rates and reduced stolon death. These cultivar differences with frequent defoliation suggest that Irrigation is more suited to frequent defoliation than Haifa.

scholarly journals Effects of Iron and Zinc Spray on Yield and Yield Components of Wheat (Triticum Aestivum L.) in Drought Stress

2013 ◽  
Vol 46 (1) ◽  
pp. 23-32 ◽  
Author(s):  
F. Monjezi ◽  
F. Vazin ◽  
M. Hassanzadehdelouei
Keyword(s):  
Drought Stress ◽  
Seed Yield ◽  
Yield Components ◽  
Block Design ◽  
Control Treatment ◽  
Yield Reduction ◽  
Irrigation Level ◽  
Seed Filling ◽  
Yield And Yield Components ◽  
Iron And Zinc

Abstract In hot and arid regions, drought stress is considered as one of the main reasons for yield reduction. To study the effect of drought stress, iron and zinc spray on the yield and yield components of wheat, an experiment was carried out during the crop seasons of 2010 and 2011 on Shahid Salemi Farm in Ahwaz as a split factorial within randomized complete block design with three replications. The main plots with irrigation factor and three levels were considered: Level A) full irrigation, Level B) stopping irrigation at pollination step, and Level C) stopping irrigation at the seed filling stage. Subsidiary plots were considered with and without iron and zinc spray. Influencing the seed filling process, in interaction with iron, wich is an important leaf's chlorophyll cation, zinc increased the seed yield. The drought stress reduced the thousand kernels weight (TKW) and the number of seeds per spike increased about 24% and 8.5% more than the one of control treatment, respectively. Using iron, as compared with control treatment, causes the increase of thousand kernels weight from 45.71 to 46.83 grams and the increase of spike from 49.51 to 51.73. Zinc spray increased seed yield and thousand kernels weight. The results obtained from the present research showed that iron and zinc spray has fairly improved the effects caused by drought stress.

scholarly journals Comparative Proteomics of Root Apex and Root Elongation Zones Provides Insights into Molecular Mechanisms for Drought Stress and Recovery Adjustment in Switchgrass

Proteomes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 3 ◽  
Author(s):  
Zhujia Ye ◽  
Sasikiran Reddy Sangireddy ◽  
Chih-Li Yu ◽  
Dafeng Hui ◽  
Kevin Howe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Drought Stress ◽  
Molecular Mechanisms ◽  
Root Zone ◽  
Root Apex ◽  
Root Tip ◽  
Leaf Water Content ◽  
Severe Drought ◽  
Proteomics Data ◽  
Drought Treatment

Switchgrass plants were grown in a Sandwich tube system to induce gradual drought stress by withholding watering. After 29 days, the leaf photosynthetic rate decreased significantly, compared to the control plants which were watered regularly. The drought-treated plants recovered to the same leaf water content after three days of re-watering. The root tip (1cm basal fragment, designated as RT1 hereafter) and the elongation/maturation zone (the next upper 1 cm tissue, designated as RT2 hereafter) tissues were collected at the 29th day of drought stress treatment, (named SDT for severe drought treated), after one (D1W) and three days (D3W) of re-watering. The tandem mass tags mass spectrometry-based quantitative proteomics analysis was performed to identify the proteomes, and drought-induced differentially accumulated proteins (DAPs). From RT1 tissues, 6156, 7687, and 7699 proteins were quantified, and 296, 535, and 384 DAPs were identified in the SDT, D1W, and D3W samples, respectively. From RT2 tissues, 7382, 7255, and 6883 proteins were quantified, and 393, 587, and 321 proteins DAPs were identified in the SDT, D1W, and D3W samples. Between RT1 and RT2 tissues, very few DAPs overlapped at SDT, but the number of such proteins increased during the recovery phase. A large number of hydrophilic proteins and stress-responsive proteins were induced during SDT and remained at a higher level during the recovery stages. A large number of DAPs in RT1 tissues maintained the same expression pattern throughout drought treatment and the recovery phases. The DAPs in RT1 tissues were classified in cell proliferation, mitotic cell division, and chromatin modification, and those in RT2 were placed in cell wall remodeling and cell expansion processes. This study provided information pertaining to root zone-specific proteome changes during drought and recover phases, which will allow us to select proteins (genes) as better defined targets for developing drought tolerant plants. The mass spectrometry proteomics data are available via ProteomeXchange with identifier PXD017441.

Genome-wide identification of AP2/ERF transcription factors in mungbean (Vigna radiata) and expression profiling of the VrDREB subfamily under drought stress

2018 ◽  
Vol 69 (10) ◽  
pp. 1009 ◽  
Author(s):  
Abdullahi Muhammad Labbo ◽  
Maryam Mehmood ◽  
Malik Nadeem Akhtar ◽  
Muhammad Jawad Khan ◽  
Aamira Tariq ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Drought Stress ◽  
Stress Tolerance ◽  
Vigna Radiata ◽  
Critical Role ◽  
Drought Stress Tolerance ◽  
Legume Crop ◽  
Genome Wide ◽  
Responsive Element ◽  
Major Factors

Mungbean (Vigna radiata L.) is a valuable legume crop grown in tropical and subtropical areas of Asia. Drought is one of the major factors hindering its growth globally. APETALA2/ethylene-responsive element factor binding proteins (AP2/ERF) are an important family of plant-specific transcription factors (TFs) involved in drought-stress tolerance. We identified 71 AP2/ERF TFs in the mungbean genome by using bioinformatics tools and classified them into subfamilies: AP2 (16 members), ERF (22), RAV (2), DREB (30) and soloist (other proteins with no domain, 1). Members of DREB play a critical role in drought-stress tolerance. Ten-day-old mungbean plants cv. AZRI-06 were exposed to drought stress by complete withholding of water for 7 days. Root samples were collected from control and drought-stressed plants, and the expression pattern of 30 identified VrDREB genes was determined by qPCR. Most VrDREB genes exhibited differential expression in response to drought. Five genes (VrDREB5, VrDREB12, VrDREB13, VrDREB22, VrDREB30) were highly expressed under drought stress and might be considered excellent candidates for further functional analysis and for improvement of mungbean drought tolerance.

scholarly journals Person - job fi t and the work commitment of IT Personnel

2016 ◽  
Vol 26 (2) ◽  
pp. 218 ◽  
Author(s):  
Therasa C. ◽  
C. Vijayabanu
Keyword(s):  
Regression Analysis ◽  
Principal Component ◽  
Attrition Rate ◽  
P Value ◽  
Work Commitment ◽  
Key Factors ◽  
Coeffi Cients ◽  
Work Autonomy ◽  
Major Factors ◽  
The Impact

Introduction: There have been given a much higher importance to employee commitment and retention since India is experiencing the highest attrition rate globally Economic Times, 2015. Hence, considering the factors of Person-job fi t to interpret the impact towards work commitment is very well essential, especially in the current scenario. Work Commitment is a vital element in any organization which has outstanding impact on productivity and functioning and hence it is very much vital to have a committed workforce which is necessary in this competitive environment and tight labour market. In the same way, there is considerable amount of evidence that if P-J fi t is high then it will have a direct impact on organization commitment also. Person-job fi t is the compatibility between person’s competency and abilities and the requirements of the job Zheng et al.2. If there exists a mismatch between person-job fi t then the consequences might result in poor work commitment, low job satisfaction and extremely lower involvement in the job. Objective: This study analyzed the key factors that contribute to Person- job compatibility among IT workers and also analyzed the relationship and impact of Person- job compatibility towards work commitment. Methods: Exploratory Factor Analysis (EFA) was used to fi lter the key factors initially, followed by a linear regression technique to determine the impact of Person- job compatibility factors in work commitment on a sample of 300 employees. EFA used Principal Component analysis for extraction and Promax for rotation. Finally regression analysis was carried out to predict the work commitment through statistically significant person-job compatibility variables. Results: The impact of person-job compatibility on work commitment was studied through regression analysis and it imply that for every unit increase in HR Policy, a 0.52 (unstandardised coeffi cients) increase in work commitment is predicted and it has been turned out as a most impacting variable to predict work commitment. The coeffi cients for Relationship (B =.330, sig =.000), HR Policies (B =.519, sig =.000), Pay and Benefi ts (B =.386, sig =.000) and Employee Growth (B =.290, sig =.001) were statistically significant, since its p-value is .000 which is smaller than .05. The coeffi cients for Work Autonomy (B =.154, sig = .081) was not statistically signifi cant, since its p-value is 0.081 which is greater than.05. Conclusion: The major factors responsible for creating work commitment among IT employees are Relationship, HR Policies and strategies, Pay and benefi ts, Work autonomy and Employee growth. The most contributing regressors which accounts for creating work commitment are HR policies, Pay and benefi ts, Employee growth and work autonomy.

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