scholarly journals VARIATIONS IN GROWTH AND PHOTOSYNTHETIC PARAMETERS OF SOME CLONAL SEMI-DWARFING AND VIGOROUS SEEDLING PEAR (Pyrus spp.) ROOTSTOCKS IN RESPONSE TO DEFICIT IRRIGATION

2020 ◽  
Vol 19 (2) ◽  
pp. 105-121
Author(s):  
Majid Zohouri ◽  
Hamid Abdollahi ◽  
Isa Arji ◽  
Vahid Abdossi

A greenhouse experiment was conducted to estimate the impacts of various deficit irrigation regimes (DIR) as 100 (control), 75 (medium DIR, MDIR) and 50% (severe DIR, SDIR) of field capacity (FC) on the growth and photosynthetic traits of five rootstocks (two vigorous seedling including Pyrus betulifolia and Dargazi seedling (P. communis L.) as well as three clonal semi-dwarfing rootstocks including OH×F69, OH×F87 and Pyrodwarf in 2016. Although in all studied rootstocks the growth and photosynthetic parameters negatively affected under MDIR and SDIR conditions, but P. betulifolia and Pyrodwarf rootstocks had the better growth rate, chlorophylls, total carbohydrates, relative water content, sub-stomatal CO2 (Ci), photosynthesis rate (PN) and instantaneous water use efficiency compared to others. Therefore, the use of P. betulifolia and Pyrodwarf (as drought tolerance rootstocks) could be more appropriate under various DIR conditions.

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
U. Lakshmi Sahitya ◽  
M. S. R. Krishna ◽  
R. Sri Deepthi ◽  
G. Shiva Prasad ◽  
D. Peda Kasim

Altering climatic conditions and water stress drastically affects the chilli crop yield. In this scenario we adapted a strategic approach for screening of elite chilli genotypes, by exploring role of seed antioxidants in stress tolerance during vegetative phase. A total of 20 chilli genotypes’ seed antioxidant potential and its effect on water stress tolerance were studied at three water regimes, namely, control (100% Field Capacity), moderate (80% Field Capacity), and severe (60% Field Capacity) stress conditions. Drought tolerance traits relative water content, chlorophyll content, and activities of superoxide dismutase and catalase enzymes were measured. A strong correlation was observed between seed antioxidants and water stress tolerant traits in seedlings. Genotypes KCa-5, KCa-6, and KCa-10 showed low quantity of H2O2 and Malondialdehyde in seeds and maintained high membrane integrity and chlorophyll content in seedlings. High content of proline in KCa-5, KCa-7, and KCa-10 seeds retained high relative water content at seedling stage under severe water stress. Present work reveals genotypic differences of hot pepper to different water regimes. Based on Principal Component Analysis (PCA) of seed antioxidant variables and drought tolerance indices twenty genotypes segregated into three clusters, namely, drought tolerant and susceptible and moderately tolerant.


2015 ◽  
Vol 10 (4) ◽  
pp. 208 ◽  
Author(s):  
Lorenzo Barbanti ◽  
Ahmad Sher ◽  
Giuseppe Di Girolamo ◽  
Elio Cirillo ◽  
Muhammad Ansar

A better understanding of plant mechanisms in response to drought is a strong premise to achieving high yields while saving unnecessary water. This is especially true in the case of biomass crops for non-food uses (energy, fibre and forage), grown with limited water supply. In this frame, we investigated growth and physiological response of two genotypes of biomass sorghum (<em>Sorghum bicolor</em> (L.) Moench) to contrasting levels of soil moisture in a pot experiment carried out in a greenhouse. Two water regimes (high and low water, corresponding to 70% and 30% field capacity) were applied to JS-2002 and Trudan-8 sorghum genotypes, respectively bred for dry sub-tropical and mild temperate conditions. Two harvests were carried out at 73 and 105 days after seeding. Physiological traits (transpiration, photosynthesis and stomatal conductance) were assessed in four dates during growth. Leaf water potential, its components and relative water content were determined at the two harvests. Low watering curbed plant height and aboveground biomass to a similar extent (ca. 􀀀70%) in both genotypes. JS-2002 exhibited a higher proportion of belowground to aboveground biomass, <em>i.e</em>., a morphology better suited to withstand drought. Despite this, JS-2002 was more affected by low water in terms of physiology: during the growing season, the average ratio in transpiration, photosynthesis and stomatal conductance between droughty and well watered plants was, respectively, 0.82, 0.80 and 0.79 in JS-2002; 1.05, 1.08 and 1.03 in Trudan-8. Hence Trudan-8 evidenced a ca. 20% advantage in the three traits. In addition, Trudan-8 could better exploit abundant moisture (70% field capacity), increasing aboveground biomass and water use efficiency. In both genotypes, drought led to very low levels of leaf water potential and relative water content, still supporting photosynthesis. Hence, both morphological and physiological characteristics of sorghum were involved in plant adaptation to drought, in accordance with previous results. Conversely, the common assumption that genotypes best performing under wet conditions are less suited to face drought was contradicted by the results of the two genotypes in our experiment. This discloses a potential to be further exploited in programmes of biomass utilization for various end uses, although further evidence at greenhouse and field level is needed to corroborate this finding.


2022 ◽  
Vol 44 (1) ◽  
Author(s):  
Mohamed Ahmed Fayek ◽  
Ahmed Abdelhady Rashedy ◽  
Amr Ebrahim Mohamed Ali

Abstract Using interstock with a potential genetic base is considered more recent and sustainable strategy for mitigating the water deficit. This investigation was carried out on transplant of Flame seedless (Vitis vinifera) grapevine grafted onto two rootstocks namely; Freedom (Vitis champinii x 1613C) and 1103Paulsen (vitis berlandieri x Vitis rupestris) with or without 1103Paulsen as interstock to determine its performance under deficit irrigation condition (50% of field capacity). The results indicated that Paulsen as rootstock or as interstock significantly increased the growth vigor of Flame seedless scion as well as the leaf content of total proline, phenols and sugars. Paulsen rootstock has decreased stomatal conductance, leaf transpiration rate and increased diffusion resistance under 50% deficit irrigation compared with grafting on Freedom rootstock. Moreover, Paulsen as interstock for Flame seedless grafted onto Freedom rootstock significantly increased relative water content accompanied by an increase in thickness of leaf anatomical characters such as midvein, lamina, palisade, xylem and phloem tissue under deficit irrigation compared with grafts without Paulsen interstock. This study suggests that using Paulsen as interstock, can be an adaptation strategy for water stress through controlling in some morphological, chemical physiological and anatomical responses of scion.


2019 ◽  
Vol 18 (6) ◽  
pp. 75-84
Author(s):  
Alireza Motallebi-Azar ◽  
István Papp ◽  
Anita Szegő

Dehydrins are proteins that play a role in the mechanism of drought tolerance. This study aimed at establishing dehydrin profile and accumulation in four local melon varieties of Iran: Mino, Dargazi, Saveii, and Semsori, as well as in a commercial variety Honeydew. Plants were treated with drought stress by adjusting the soil water content to 75, 50, 40, 30 and 20% of field capacity (FC) by withholding water. Water status of plants was monitored based on the seedling fresh weight (FW) and relative water content of leaves (RWC). Total protein content was extracted, then heat-stable protein (HSP) fraction was isolated for each variety and water stress treatment. After SDS-PAGE of HSP, Western blotting analysis was carried out with Anti-dehydrin rabbit (primary) and Goat anti rabbit (secondary) antibodies. ANOVA results showed that with decreasing FC below 75%, FW and RWC decreased, but these changes significantly varied among genotypes. On the basis of FW and RWC data under different drought stress treatments, the following drought-tolerant ranking was established: Mino > Dargazi > Saveii and Honeydew > Semsori, from tolerant to sensitive order. Results of Western blot analysis showed that expression of some proteins with molecular weights of 19–52 kDa was induced in the studied varieties under drought stress (% FC). Expression level of the dehydrin proteins in different varieties was variable and also depending on the drought stress level applied. However, dehydrin proteins (45 and 50 kDa) showed strong expression levels in all varieties under severe drought stress (20% FC). The abundance of dehydrin proteins was higher in tolerant varieties (Mino and Dargazi) than in moderate and drought sensitive genotypes. Consequently, dehydrins represent a potential marker for selection of genotypes with enhanced drought tolerance.


1997 ◽  
Vol 24 (1) ◽  
pp. 49 ◽  
Author(s):  
K. M. Volkmar

This experiment as undertaken to determine the efects of soil drying around the nodal and/or seminal root systems on the shoot growth of wheat (Triticum aestivum L.). Two split-root experiments were conducted, the first on newly emerged nodal roots of 18-day-old wheat plants, the second on 25-day-old plants. In both experiments, nodal and seminal roots were isolated from one another and water was withheld from either the nodal root chamber, the seminal root chamber, or both, over 6 days. In the first experiment, leaf growth was unaffected by withholding water from very short nodal roots, even though leaf relative water content of the droughted plants decreased. By comparison, both leaf elongation rate and relative water content decreased by withholding water from the seminal roots. On plants that were 1 week older, leaf growth rate and leaf relative water content decreased when nodal roots were drought-stressed. Leaf growth rate of seminal root droughted plants was more impaired than their nodal root counterparts, even though leaf relative water contents of the two treatments were the same. In both experiments, drought stress applied to the nodal root system enhanced nodal root growth more than seminal roots. These results suggest that seminal and nodal roots perceive and respond to drought stress differently with respect to the nature of the message conveyed to the shoots.


2001 ◽  
Vol 48 (4) ◽  
pp. 353-361 ◽  
Author(s):  
E. Farshadfar ◽  
M. Farshadfar ◽  
J. Sutka

To study the properties of some drought tolerance criteria and  agronomic characters in wheat, an eight-parental diallel cross, excluding reciprocals, was grown in a randomized complete block design with three replications under two different water regimes (irrigated and rainfed) for two years in the College of Agriculture at Razi University, Kermanshah, Iran. High broad-sense heritability estimates were observed for harvest index, grain yield, and earliness. Additive gene action was found to be predominant for grain yield, harvest index, relative water content and chlorophyll fluorescence. The results of combining ability analysis revealed that Plainsman was the best general combiner and Plainsman × Kobomugi was the best specific combination for improving drought tolerance. The pooled analysis of variance for combining ability over rainfed conditions reflected that the GCA × environment interaction was not significant for harvest index and chlorophyll fluorescence, and the SCA × environment interaction was  non-significant for relative water content and relative water loss, indicating that genes controlling osmoregulation and the other physiological traits mentioned are not affected in these varieties by different rainfed conditions and hence show static stability.


Author(s):  
K.D. Nkoana ◽  
Abe Shegro Gerrano ◽  
E.T. Gwata

The genetic potential for drought tolerance in cowpea within the small holder sector has not been fully exploited in South Africa. Thus, a drought evaluation experiment was conducted at the ARC-VOP to evaluate 28 cowpea germplasm accessions including two controls viz. IT96D-602 (drought tolerant) and TVU7778 (susceptible to drought) in the drought screening house using plastic box evaluation method in January, 2017. Genotypes raised for three weeks were subjected to 5 weeks of water stress treatment to determine their physiological response through leaf wilting index, relative water content and proline content followed by re-watering to determine genotype (s) with ability to recover from drought stress. Analyses of variance showed highly significant differences in response to moisture stress among the cowpea accessions for the selected physiological traits except for leaf wilting index at week two of drought stress. Stem greenness and recovery appeared to be a reliable indicator of drought tolerant genotypes which was readily observed in Acc1257, Acc1168, Acc2355, IT96D-602 and Acc5352 which also correlated significantly and positively with relative water content and proline content. The genotypes responded differently to drought stress indicating that there is sufficient genetic variability that can be utilized further in breeding for drought stress within the cowpea species.


2021 ◽  
Vol 25 (05) ◽  
pp. 937-944
Author(s):  
Xinyang Bai

Improving potassium (K) use efficiency (KUE) is beneficial for the sustainable production of cereal crops. In this study, the effects of K input level on its uptake and agronomic trait of the winter wheat under deficit irrigation were investigated in K deprivation responses, using two cultivars contrasting (low-K tolerant cultivar Kenong 9204 and K deprivation sensitive one Jimai 120). Under sufficient-K treatment (K180, SK), the two cultivars showed similar K contents, and K accumulation, biomass, photosynthetic parameters in upper expanded leaves, including yield components. Under deficient-K (K60, DK) condition, both cultivars showed varied behaviors of the K-associated traits, physiological parameters, growth and agronomic traits; however, better response was observed in Kenong 9204 than Jimai 120. These results suggested the essential roles of low-K tolerant cultivars under the K-saving management together with deficit irrigation. Two genes of the potassium transporter (HAK) family, TaHAK3 and TaHAK5, showed expression of significantly upregulated upon K deprivation, with much more transcripts shown in the K-deprived Kenong 9204 plants than Jimai 120 ones. Transgene analysis on the HAK genes validated their positive roles in modulating the K accumulation and biomass production of plants under low-K condition. These results indicated that distinct HAK family genes are transcriptionally regulated underlying K deprivation signaling and contribute to plant K uptake and biomass production under low-K conditions. This study suggested the drastically genetic variation on K uptake and biomass production across winter wheat cultivars treated by K- and water-saving conditions, associated with transcription efficiency of the distinct HAK genes which modulate K uptake, growth and development of plants. © 2021 Friends Science Publishers


2017 ◽  
Vol 62 (3) ◽  
pp. 213-227 ◽  
Author(s):  
Manal Hefny ◽  
Abdelraheim Ali ◽  
Tarek Byoumi ◽  
Mohamed Al-Ashry ◽  
Salah Okasha

Water scarcity is a universal environmental constraint for agricultural sustainability and production. Two field experiments were accomplished during the 2012 and 2013 growing seasons in two sites: the experimental farm of Suez Canal University, Ismailia and Romana Province, North Sinai, Egypt to evaluate 21 genotypes of maize comprising six inbred lines and their 15 F1 crosses for their drought tolerance. The experiments were arranged as a split-plot design with three replications, where moisture levels (100 and 50% of evapotranspiration) and maize genotypes were allocated to main plots and sub-plots, respectively. Results showed reduction in performance for most measured traits in response to water stress with varying degrees with yield plant-1 being the most affected. Inversely, proline and relative water content and anthesis-silking interval were increased. Correlation results confirmed the reduced grain yield with the increasing anthesis-silking interval, and suggested kernels row-1, relative water content, peroxidase activity and rows ear-1 in Ismailia, and rows ear-1, relative water content, peroxidase activity, kernel weight in Romana were indirect selection criteria for increasing yield in water scarcity environments. Principal component (PC) analysis showed that three PCs having Eigen value >1 explained 70.67 and 70.16%; 69.79 and 71.38% of the total variability among genotypes in control and stress conditions in Ismailia and Romana, respectively. The crosses P1?P3, P4?P6, P3?P5 and P1?P5 were classified as drought tolerant under Ismailia and Romana conditions. On the other hand, P1xP4, P3xP4, and P4 were considered as drought sensitive in Ismailia conditions. In addition, P5, P2?P4, P1?P4 and P5?P6 were the most affected by water deficiency under Romana conditions.


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