scholarly journals The Effects of Drought and Re-Watering on Non-Structural Carbohydrates of Pinus tabulaeformis Seedlings

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 281
Author(s):  
Xinyi Guo ◽  
Changhui Peng ◽  
Tong Li ◽  
Jingjing Huang ◽  
Hanxiong Song ◽  
...  
Keyword(s):  
Photosynthetic Rate ◽  
Control Level ◽  
Pinus Tabulaeformis ◽  
Severe Drought ◽  
Legacy Effect ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Pinus Tabulaeformis Carr ◽  
Effects Of Drought ◽  
Manipulation Experiment

Intense and frequent drought events strongly affect plant survival. Non-structural carbohydrates (NSCs) are important “buffers” to maintain plant functions under drought conditions. We conducted a drought manipulation experiment using three-year-old Pinus tabulaeformis Carr. seedlings. The seedlings were first treated under different drought intensities (i.e., no irrigation, severe, and moderate) for 50 days, and then they were re-watered for 25 days to explore the dynamics of NSCs in the leaves, twigs, stems, and roots. The results showed that the no irrigation and severe drought treatments significantly reduced photosynthetic rate by 93.9% and 32.6% for 30 days, respectively, leading to the depletion of the starch storage for hydraulic repair, osmotic adjustment, and plant metabolism. The seedlings under moderate drought condition also exhibited starch storage consumption in leaves and twigs. After re-watering, the reduced photosynthetic rate recovered to the control level within five days in the severe drought group but showed no sign of recovery in the no irrigation group. The seedlings under the severe and moderate drought conditions tended to invest newly fixed C to starch storage and hydraulic repair instead of growth due to the “drought legacy effect”. Our findings suggest the depletion and recovery of starch storage are important strategies for P. tabulaeformis seedlings, and they may play key roles in plant resistance and resilience under environmental stress.

scholarly journals Enhancement of drought tolerance in diverse Vicia faba cultivars by inoculation with plant growth-promoting rhizobacteria under newly reclaimed soil conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elsayed Mansour ◽  
Hany A. M. Mahgoub ◽  
Samir A. Mahgoub ◽  
El-Sayed E. A. El-Sobky ◽  
Mohamed I. Abdul-Hamid ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Severe Drought ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Effects Of Drought

AbstractWater deficit has devastating impacts on legume production, particularly with the current abrupt climate changes in arid environments. The application of plant growth-promoting rhizobacteria (PGPR) is an effective approach for producing natural nitrogen and attenuating the detrimental effects of drought stress. This study investigated the influence of inoculation with the PGPR Rhizobium leguminosarum biovar viciae (USDA 2435) and Pseudomonas putida (RA MTCC5279) solely or in combination on the physio-biochemical and agronomic traits of five diverse Vicia faba cultivars under well-watered (100% crop evapotranspiration [ETc]), moderate drought (75% ETc), and severe drought (50% ETc) conditions in newly reclaimed poor-fertility sandy soil. Drought stress substantially reduced the expression of photosynthetic pigments and water relation parameters. In contrast, antioxidant enzyme activities and osmoprotectants were considerably increased in plants under drought stress compared with those in well-watered plants. These adverse effects of drought stress reduced crop water productivity (CWP) and seed yield‐related traits. However, the application of PGPR, particularly a consortium of both strains, improved these parameters and increased seed yield and CWP. The evaluated cultivars displayed varied tolerance to drought stress: Giza-843 and Giza-716 had the highest tolerance under well-watered and moderate drought conditions, whereas Giza-843 and Sakha-4 were more tolerant under severe drought conditions. Thus, co-inoculation of drought-tolerant cultivars with R. leguminosarum and P. putida enhanced their tolerance and increased their yield and CWP under water-deficit stress conditions. This study showed for the first time that the combined use of R. leguminosarum and P. putida is a promising and ecofriendly strategy for increasing drought tolerance in legume crops.

scholarly journals Effects of root phenotypic changes on the deep rooting of Populus euphratica seedlings under drought stresses

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6513 ◽  
Author(s):  
Zi-qi Ye ◽  
Jian-ming Wang ◽  
Wen-juan Wang ◽  
Tian-han Zhang ◽  
Jing-wen Li
Keyword(s):  
Drought Stress ◽  
Root Architecture ◽  
Mass Fraction ◽  
Populus Euphratica ◽  
Severe Drought ◽  
Root Depth ◽  
Phenotypic Changes ◽  
Positive Effects ◽  
Drought Conditions ◽  
Moderate Drought

Background Deep roots are critical for the survival of Populus euphratica seedlings on the floodplains of arid regions where they easily suffer drought stress. Drought typically suppresses root growth, but P. euphratica seedlings can adjust phenotypically in terms of root-shoot allocation and root architecture and morphology, thus promoting deep rooting. However, the root phenotypic changes undertaken by P. euphratica seedlings as a deep rooting strategy under drought conditions remain unknown. Methods We quantified deep rooting capacity by the relative root depth (RRD), which represents the ratio of taproot length to plant biomass and is controlled by root mass fraction (RMF), taproot mass fraction (TRMF), and specific taproot length (STRL). We recorded phenotypic changes in one-year-old P. euphratica seedlings under control, moderate and severe drought stress treatments and assessed the effects of RMF, TRMF, and STRL on RRD. Results Drought significantly decreased absolute root depth but substantially increased RRD via exerting positive effects on TRMF, RMF, and STRL. Under moderate drought, TRMF contributed 55%, RMF 27%, and STRL 18% to RRD variation. Under severe drought, the contribution of RMF to RRD variation increased to 37%, which was similar to the 41% for TRMF. The contribution of STRL slightly increased to 22%. Conclusion These results suggest that the adjustments in root architecture and root-shoot allocation were predominantly responsible for deep rooting in P. euphratica seedlings under drought conditions, while morphological changes played a minor role. Moreover, P. euphratica seedlings rely mostly on adjusting their root architecture to maintain root depth under moderate drought conditions, whereas root-shoot allocation responds more strongly under severe drought conditions, to the point where it plays a role as important as root architecture does on deep rooting.

scholarly journals Resilience of Resprouting Temperate Forests is Diminished by Coupled Severe Drought and Fire

2021 ◽  
Author(s):  
Eli Ryan Bendall ◽  
Michael Bedward ◽  
Matthias Boer ◽  
Hamish Clarke ◽  
Luke Collins ◽  
...  
Keyword(s):  
Tree Mortality ◽  
Seedling Recruitment ◽  
Temperate Forests ◽  
Dry Forest ◽  
Drought Severity ◽  
Severe Drought ◽  
Forest Types ◽  
Juvenile Mortality ◽  
Moderate Drought ◽  
Effects Of Drought

Abstract Elevated tree mortality and reduced recruitment of new trees linked to drought and fires has been reported across a range of forests over the last few decades. Forests that resprout new foliage epicormically from buds beneath the bark are considered highly resilient to disturbance, but are potentially at risk of elevated mortality, demographic shifts and changes to species composition due to synergistic effects of drought and fire. Despite this, the effects of drought-fire interactions on such forests remain largely unknown. We assessed the effects of drought severity and fire frequency on juvenile mortality, post-fire seedling recruitment and replacement of juvenile trees (balance of recruitment minus mortality) following fire. We compared dry ridgetop and wet gully assemblages across a temperate forest in southern Australia. Both forest types experienced higher rates of fire-induced juvenile mortality in areas that had experienced severe drought compared to moderate drought, though mortality rates were generally low across all drought and fire combinations. This result indicated that topographic position (i.e. wet gullies) did little to moderate juvenile mortality when exposed to severe drought plus fire. In wet forest, severe drought also reduced recruitment and replacement of dead juveniles by post-fire seedlings compared to moderate drought. In dry forest net-negative replacement increased with the severity of drought. Across both forest types, the total pool of juveniles was reduced under severe drought. Future increases in the frequency of coupled severe drought and fire will likely increase the susceptibility of resilient temperate forests to major changes in structure and function.

scholarly journals Computational Analysis for Rainfall Characterization and Drought Vulnerability in Peninsular India

2021 ◽  
Vol 2021 ◽  
pp. 1-27
Author(s):  
M. P. Akhtar ◽  
Firoz Alam Faroque ◽  
L. B. Roy ◽  
Mohd. Rizwanullah ◽  
Mukesh Didwania
Keyword(s):  
Tamil Nadu ◽  
Drought Index ◽  
Extreme Drought ◽  
Annual Rainfall ◽  
Drought Indices ◽  
Severe Drought ◽  
Drought Vulnerability ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Standard Deviations

This paper analyzes the historical rainfall characterization and drought conditions in two major southern states of India, namely, Tamil Nadu and Karnataka, through estimation of meteorological drought indices, namely, drought index (DI), Palmer drought index (PDI), and standardized precipitation index (SPI). Monthly and yearly rainfall data, including temperature, have been considered for 110 years. Deficient rainfall conditions have been identified and compared using annual rainfall classification thresholds. Annual rainfall variability and trend have been estimated using Mann–Kendall test and Sen’s slope test. Comparative study on results implies that drought characterization using SPI may amply facilitate the standardization of threshold classification for severity and frequency. Based on threshold classification, it is found that Tamil Nadu witnessed on an average 11 years of moderate drought, 4.36 years of severe drought, and 1.32 years of extreme drought conditions with standard deviations of 4.28, 1.87, and 1.63 years, respectively, during the study period, whereas Karnataka witnessed on an average 9.74 years of moderate drought, 3.91 years of severe drought, and 2.30 years of extreme drought conditions with standard deviations of 4.54, 2.04, and 2.21 years, respectively, during the study period. According to the analysis, drought vulnerability in Tamil Nadu was higher than in Karnataka, based on the number of dry and wet years in terms of SPI threshold values and area covered over 110 years. Karnataka was more susceptible in terms of severity. When compared with other indices, analysis based on drought indices indicates that a single variable-based estimation using SPI is easy to assess and may be significant and definitive in terms of decision making for prioritizing drought mitigation measures in the study area in case of inadequate available data for multiple variable-based drought analysis.

scholarly journals Effect of moderate and severe drought stress on the pre-anthesis development and yield formation of oats

1991 ◽  
Vol 63 (5) ◽  
pp. 379-389 ◽  
Author(s):  
P. Peltonen-Sainio
Keyword(s):  
Drought Stress ◽  
Water Deficit ◽  
Morphological Characteristics ◽  
Developmental Rate ◽  
Yield Potential ◽  
Severe Drought ◽  
Moderate Drought ◽  
Effects Of Drought ◽  
Growing Conditions ◽  
Yield Formation

Greenhouse experiments were conducted at the University of Helsinki, Department of Crop Husbandry in 1989 and 1990 to provide information on the effects of drought stress on the developmental rate of the panicle, formation and abortion of florets, and formation of yield components in two oat cultivars, both adapted to the northern marginal growing conditions. Moderate water deficit and severe drought stress did not affect the developmental rate of the panicle, but the pre-anthesis and post-anthesis architecture changed considerably; leaves unrolled later, the number of green leaves was lower, the internodes lengthened less, and the inflorescence was shorter as a consequence of water deficit. Drought stress decreased the number of fertile florets in the panicle significantly, in the lower clusters of branches in particular. In the cultivar “Puhti”, 57 % of the fertile florets aborted as a consequence of moderate drought stress and 89 % as a result of severe drought stress when compared to well-watered individuals, while in “Virma”, a cultivar of significantly higher yield potential, 80 °lo and 90 % of the fertile florets wilted, respectively. In addition, water deficit caused considerable losses in all the morphological characteristics measured. Further implications of these results for yield formation are discussed.

scholarly journals Correlating drought conservation practices and drought vulnerability in a tropical agricultural system

2018 ◽  
Vol 33 (3) ◽  
pp. 279-291 ◽  
Author(s):  
Nora L. Álvarez-Berríos ◽  
Sandra Soto-Bayó ◽  
Eva Holupchinski ◽  
Stephen J. Fain ◽  
William A. Gould
Keyword(s):  
Puerto Rico ◽  
Cover Crops ◽  
Spatial Databases ◽  
Extreme Drought ◽  
Climate Projections ◽  
Severe Drought ◽  
Conservation Practices ◽  
Eastern Region ◽  
Drought Conditions ◽  
Moderate Drought

AbstractRecent droughts in Puerto Rico and throughout the Caribbean have emphasized the region's agricultural vulnerability to this hazard and the increasing need for adaptation mechanisms to support sustainable production. In this study, we assessed the geographic extent of agricultural conservation practices incentivized by US Department of Agriculture Natural Resources Conservation Service (NRCS) and evaluated their large-scale contribution to drought adaptability. We identified concentrations of drought-related practices (e.g. cover crops, ponds) applied between 2000 and 2016. Using information from spatial databases and interviews with experts, we assessed the spatial correlation between these practices and areas exposed to drought as identified by the US Drought Monitor. Between 2000 and 2016, Puerto Rico experienced seven drought episodes concentrated around the south, east and southeastern regions. The most profound drought occurred between 2014 and 2016 when the island experienced 80 consecutive weeks of moderate drought, 48 of severe drought and 33 of extreme drought conditions. A total of 44 drought-related conservation practices were applied at 6984 locations throughout 860 km2 of farmlands between 2000 and 2016 through the NRCS-Environmental Quality Incentives Program (EQIP). Practices related to water availability were statistically clustered along the coasts, whereas soil and plant health practices were clustered in the mountainous region. While these concentrations strongly correlated with areas exposed to moderate drought conditions, >80% did not coincide with areas that experienced severe or extreme drought conditions, suggesting that areas highly exposed to drought conditions generally lacked drought preparedness assisted by EQIP. Climate projections indicate an increase in the frequency and intensity of drought events, particularly in the eastern region of Puerto Rico. Our analysis highlighted the need to implement more conservation practices in these areas subject to drought intensification and exposure. Government programs intended to address vulnerabilities and enhance capacity and resilience may not be reaching areas of highest exposure. Recommendations include raising producer awareness of past and future exposure and making programs more accessible to a broader audience.

scholarly journals Influence of Different Typ es Mycorrhizal Fungi on Crop Productivity

2014 ◽  
Vol 2 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Raminder Kaur ◽  
Avtar Singh ◽  
J Kang
Keyword(s):  
Drought Stress ◽  
Mycorrhizal Fungi ◽  
Crop Productivity ◽  
Severe Drought ◽  
Drought Condition ◽  
Mycorrhizal Association ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Zinc Nutrition ◽  
Mycorrhizal Plants

Mycorrhizal fungi greatly enhanced the ability of plants to take up phosphorus and other nutrients those are relatively immobile and exist in low concentration in the soil solution. Fungi can be important in the uptake of other nutrients by the host plant. Zinc nutrition is most commonly reported as being influenced by the association, although uptake of copper (Cu) , iron, N, K, Ca and Mg has been reported to be enhanced. Water uptake may be improved by mycorrhizal association, making more resistant to drought condition. Often both water and nutrient uptake are higher in drought stressed mycorrhizal plants than in non mycorrhizal plants. The fungal strands are capable of altering the water potential of plants and can only alleviate moderate drought stress and in more severe drought conditions they become ineffective.

scholarly journals Quantifying the spatial extent and intensity of recent extreme drought events in the Amazon rainforest and their impacts on the carbon cycle

2020 ◽  
Author(s):  
Phillip Papastefanou ◽  
Christian S. Zang ◽  
Zlatan Angelov ◽  
Aline Anderson de Castro ◽  
Juan Carlos Jimenez ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Amazon Basin ◽  
State Of The Art ◽  
Amazon Region ◽  
Extreme Drought ◽  
Spatial Extent ◽  
Amazon Rainforest ◽  
Severe Drought ◽  
Drought Conditions ◽  
Moderate Drought

Abstract. Over the last decades, the Amazon rainforest was hit by multiple severe drought events. Here we assess the severity and spatial extent of the extreme drought years 2005, 2010, and 2015/2016 in the Amazon region and their impacts on the carbon cycle. As an indicator of drought stress in the Amazon rainforest, we use the widely applied maximum cumulative water deficit (ΔMCWD). Evaluating an ensemble of ten state-of-the-art precipitation datasets for the Amazon region, we find that the spatial extent of the drought in 2005 ranges from 2.8 to 4.2 (mean = 3.2) million km2 (46–71 % of the Amazon basin, mean = 53 %) where ΔMCWD indicates at least moderate drought conditions (ΔMCWD anomaly

Can wild lentil genotypes help improve water use and transpiration efficiency in cultivated lentil?

2018 ◽  
Vol 16 (5) ◽  
pp. 459-468 ◽  
Author(s):  
Linda Yuya Gorim ◽  
Albert Vandenberg
Keyword(s):  
Drought Tolerance ◽  
Water Use ◽  
Drought Indices ◽  
Severe Drought ◽  
Transpiration Efficiency ◽  
Drought Tolerant ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Plant Level ◽  
Wild Lentil

AbstractClimate change forecasts point to increased frequency of droughts which may affect plant growth. For protein crops such as lentil, genetic improvement of both water use and drought tolerance is necessary. Wild lentil species are known to have evolved in drought prone areas and can be introgressed into cultivated lentil, making them candidates for the evaluation of high transpiration efficiency (TE) and drought tolerance. We assessed TE, water use and drought tolerance at the plant level for five wild lentil species and in cultivated lentil. Under fully watered and moderate drought conditions, wild lentil genotypes consumed significantly less water to fix similar or more dry matter compared with their cultivated counterparts. Under severe drought conditions, the wild lentil genotype L. ervoides IG 72815 had significantly higher TE compared with L. culinaris Eston. Lens ervoides L-01-827A, had significantly higher yield compared with all other species in the presence or absence of drought and showed significantly higher (α = 5%) TE under moderate drought. Drought susceptibility index was identified as a tool to identify drought-tolerant lentil genotypes grown under severe drought. The numerous small seeds of wild lentil made it difficult to estimate drought indices that are weight based and require formulae that incorporate seed numbers.

scholarly journals Role of Ascorbic acid, Glutathione and Proline Applied as Singly or in Sequence Combination in Improving Chickpea Plant through Physiological Change and Antioxidant Defense under Different Levels of Irrigation Intervals

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1702 ◽  
Author(s):  
Hossam S. El-Beltagi ◽  
Heba I. Mohamed ◽  
Mahmoud R. Sofy
Keyword(s):  
Ascorbic Acid ◽  
Drought Stress ◽  
Plant Growth ◽  
Antioxidant Defense ◽  
Harmful Effect ◽  
Antioxidant Defense System ◽  
Severe Drought ◽  
Chickpea Plant ◽  
Moderate Drought ◽  
Effects Of Drought

In recent years, the harmful effects of drought stress have been be mitigated by using bioactive compounds such as antioxidants and osmolytes. In this research, pot experiments were carried out to investigate the effects of ascorbic acid, glutathione and proline on alleviating the harmful effect of drought stress in chickpea plants during season 2017. Chickpea plant seeds were soaked in ascorbic acid (0.75 mM), glutathione (0.75 mM), proline (0.75 mM) singly and/or in sequence combinations for 4 h and then planted in pots. The pots were irrigated with water after seven days (to serve as control), after 14 days (moderate drought stress) and after 28 days (severe drought stress). The sequence combination of antioxidants and proline under drought stress has not been studied yet. The results showed significantly decreased in plant growth, yielding characteristics, photosynthetic pigments and soluble protein content in response to moderate and severe drought stress. Moreover, treatment with antioxidants caused increment the antioxidant enzyme activity, non-enzymatic antioxidant (ascorbic acid and glutathione) contents and endogenous proline in stressed and unstressed plants. In conclusion, The sequence combination of antioxidants and proline caused improvement in plant growth under drought stress by up-regulating the antioxidant defense system and osmolyte synthesis.

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