scholarly journals Interactive Effects of Intraspecific Competition and Drought on Stomatal Conductance and Hormone Concentrations in Different Tomato Genotypes

2021 ◽  
Author(s):  
Yang Gao ◽  
Yueping Liang ◽  
Shuang Li ◽  
Zhuanyun Si ◽  
Abdoul.Kader.Mounkaila Hamani
Keyword(s):  
Stomatal Conductance ◽  
Intraspecific Competition ◽  
Plant Response ◽  
Stomatal Opening ◽  
Interactive Effects ◽  
Root Competition ◽  
Soil Drought ◽  
Severe Drought ◽  
Ethylene Evolution ◽  
Tomato Genotypes

Abstract We elucidated the effects of intraspecific competition on plant growth, stomatal opening and hormone concentrations in different tomato genotypes under different water regimes. Intraspecific competition reduced plant leaf area and stomatal conductance (gs) of wild-type tomato (Ailsa Craig), which was accompanied by abscisic acid (ABA) accumulation and ethylene evolution. Intraspecific competition-induced decrease in gs was absent in flacca, an ABA-deficient mutant, and in never-ripe, a partially ethylene-insensitive genotype, indicating ABA and ethylene involved in plant response to intraspecific competition. As soil water becomes dry, the competition decreased gs by elevating ABA and ethylene accumulations. Under severe drought, the competition-induced decline in gs was covered by the severe drought-induced decrease in gs, as hydraulic signals most probably dominate. Absence of canopy competition had no significant influence on plant stomatal opening of well-watered tomato, due to canopy separation minimized the plant neighbor sensing by ethylene and other signals. Whereas under water deficit condition, absence of canopy competition significantly reduced ABA accumulation in roots and then stomatal conductance, indicating the belowground neighbour detection signals maybe enhanced by soil drought. Absence of root competition increased ethylene evolution, confirming the importance of ethylene in neighbor detection and plant response to environmental stress.

scholarly journals Interactive Effects of Intraspecific Competition and Drought on Stomatal Conductance and Hormone Concentrations in Different Tomato Genotypes

Horticulturae ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 45
Author(s):  
Yang Gao ◽  
Yueping Liang ◽  
Yuanyuan Fu ◽  
Zhuanyun Si ◽  
Abdoul Kader Mounkaila Hamani
Keyword(s):  
Stomatal Conductance ◽  
Intraspecific Competition ◽  
Stomatal Opening ◽  
Root Competition ◽  
Severe Drought ◽  
Full Irrigation ◽  
Wild Type ◽  
Ethylene Evolution ◽  
Irrigation Amount ◽  
Tomato Genotypes

Plant physiological responses to various stresses are characterized by interaction and coupling, while the intrinsic mechanism remains unclear. The effects of intraspecific competition on plant growth, stomatal opening, and hormone concentrations were investigated with three tomato genotypes (WT-wild type, Ailsa Craig; FL-a abscisic acid (ABA) deficient mutant, flacca; NR-a partially ethylene-insensitive genotype) under two water regimes (full irrigation, irrigation amount = daily transpiration; deficit irrigation, 60% of irrigation amount in full irrigation) in this study. Three kinds of competitions were designed, i.e., root and canopy competition, non-root competition, and non-canopy competition, respectively. Intraspecific competition reduced plant leaf area and stomatal conductance (gs) of wild-type tomato, accompanied by ABA accumulation and ethylene evolution. Intraspecific competition-induced decrease in gs was absent in FL and NR, indicating ABA and ethylene involved in plant response to intraspecific competition. As soil water becomes dry, the competition decreased gs by elevating ABA and ethylene accumulations. Under severe drought, the competition-induced decline in gs was covered by the severe drought-induced decrease in gs, as hydraulic signals most probably dominate. The absence of canopy competition insignificantly influenced plant stomatal opening of well-watered tomato, as canopy separation minimized the plant neighbor sensing by ethylene and other signals. Whereas under water deficit condition, the absence of canopy competition significantly reduced ABA accumulation in roots and then stomatal conductance, indicating the belowground neighbor detection signals maybe enhanced by soil drought. The absence of root competition increased ethylene evolution, confirming the importance of ethylene in neighbor detection and plant response to environmental stress.

scholarly journals The Response of Soybean (glycine max (l.) Meer.) Varieties from the Tropical Region to Five Watering Regimes under a Controlled Environment

2018 ◽  
Vol 1 (2) ◽  
Keyword(s):  
Glycine Max ◽  
Drought Stress ◽  
Stomatal Conductance ◽  
Water Supply ◽  
Dry Season ◽  
Plant Response ◽  
Tropical Region ◽  
Transpiration Efficiency ◽  
Wide Range ◽  
Glycine Max L

In some rice dominated tropical regions, such as in Indonesia, soybeans are an increasingly important dry season crop which are often exposed to periods of drought stress. The morphological and physiological responses, which could lead to some tolerance to water stress, may vary between varieties. By better understanding the plant response to drought stress and finding if these responses vary between varieties better dry season production could be achieved. An experiment was conducted to compare the response of four varieties of soybean (glycine max (l.) Meer.) to five watering regimes, with the objective of determining the response of common soybean varieies across a wide range of water supply. Plant response to water supply was measured using gas exchange measurement with the rate of photo synthesis decreasing progressively from well watered to dry conditions across the four varieties. A correlation of stomatal conductance and transpiration rate has a close relationship with photosynthetic rate, where stomatal conductance of Burangrang variety has higher value than other varieties. Varieties Burangrang and Argomulyo stomatal conductances are higher value than those of Anjasmoro and Grobogan varieties. In a deficit of water condition, the Argomulyo varieties have a higher value of transpiration efficiency and significantly different than the other three varieties. The transpiration efficiency significantly declined for treatments watered once every two or three weeks. The transpiration efficiency values of Agromulyo and Burangrang varieties were significantly higher than another varieties.

scholarly journals Research on Occurrence and Development of Pasture Drought Events in Alpine Grassland using the Drought Threshold

2018 ◽  
Author(s):  
Tiaofeng Zhang ◽  
Lin Li ◽  
Hongbin Xiao ◽  
Hongmei Li
Keyword(s):  
Soil Moisture ◽  
Alpine Grassland ◽  
Soil Drought ◽  
Severe Drought ◽  
Drought Event ◽  
Drought Intensity ◽  
Quantitative Expression ◽  
Initial Soil Moisture ◽  
Initial Soil ◽  
The Relationship

Abstract. Pasture is vital to livestock husbandry development in Qinghai and even in North China. Drought is the primary meteorological disaster that affects pasture, but insufficient soil moisture is the most prominent cause of pasture drought. Timely and accurate determination of the soil moisture threshold of pasture is important for objective recognition and monitoring of the occurrence and development of pasture drought. This study aims at investigating pasture responses to soil drought as well as quantitative expression of soil drought degree and drought threshold. Test plots were selected from the pasture test station. Five testing groups were set according to coverage rate (0–100 %) at the initiation the pasture growth period. The impacts of profile moisture characteristics, drought threshold, and precipitation on duration of pasture drought were studied. Research results have demonstrated that moisture in the soil profile below 20 cm decreases slightly throughout drought events in alpine grassland. Changes of soil moisture in the 0–20 cm layer can generally reflect drought stress of the pasture. In the process of a drought event, the relationship between soil water storage and cumulative relative water loss can be expressed via a logarithmic linear equation. Quantitative expression of drought degree in grasslands can be realized by transforming the slope of this equation into the index D with an interval of [0, 1]. The occurrence rates of mild drought,moderate drought, and severe drought were 0.36, 0.45, and 0.70, respectively. The duration of severe drought was closely related with initial soil moisture. The relationship between duration of drought and the necessary minimum precipitation can be expressed by an exponential equation. Values of the D index can express soil drought intensity and pasture drought intensity. The durations for different grades of drought events were correlated with both initial soil moisture and previous precipitation. The conclusions of this study can provide scientific references for the objective understanding onoccurrence, development, monitoring, and early warning of pasture drought.

scholarly journals What is the Difference between the Response of Grass Pea (Lathyrus sativus L.) to Salinity and Drought Stress?—A Physiological Study

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 833 ◽  
Author(s):  
Barbara Tokarz ◽  
Tomasz Wójtowicz ◽  
Wojciech Makowski ◽  
Roman J. Jędrzejczyk ◽  
Krzysztof M. Tokarz
Keyword(s):  
Drought Stress ◽  
Crop Productivity ◽  
Lathyrus Sativus ◽  
Soil Drought ◽  
Severe Drought ◽  
Chemical Stress ◽  
Plant Tolerance ◽  
Grass Pea ◽  
Physiological Level ◽  
Lathyrus Sativus L

Understanding the mechanisms of plant tolerance to osmotic and chemical stress is fundamental to maintaining high crop productivity. Soil drought often occurs in combination with physiological drought, which causes chemical stress due to high concentrations of ions. Hence, it is often assumed that the acclimatization of plants to salinity and drought follows the same mechanisms. Grass pea (Lathyrus sativus L.) is a legume plant with extraordinary tolerance to severe drought and moderate salinity. The aim of the presented study was to compare acclimatization strategies of grass pea seedlings to osmotic (PEG) and chemical (NaCl) stress on a physiological level. Concentrations of NaCl and PEG were adjusted to create an osmotic potential of a medium at the level of 0.0, −0.45 and −0.65 MPa. The seedlings on the media with PEG were much smaller than those growing in the presence of NaCl, but had a significantly higher content percentage of dry weight. Moreover, the stressors triggered different accumulation patterns of phenolic compounds, soluble and insoluble sugars, proline and β-N-oxalyl-L-α,β-diamino propionic acid, as well as peroxidase and catalase activity. Our results showed that drought stress induced a resistance mechanism consisting of growth rate limitation in favor of osmotic adjustment, while salinity stress induced primarily the mechanisms of efficient compartmentation of harmful ions in the roots and shoots. Furthermore, our results indicated that grass pea plants differed in their response to drought and salinity from the very beginning of stress occurrence.

scholarly journals Opportunistic survival strategy ofWelwitschia mirabilis: recent anatomical and ecophysiological studies elucidating stomatal behaviour and photosynthetic potential

Botany ◽  
2017 ◽  
Vol 95 (12) ◽  
pp. 1109-1123 ◽  
Author(s):  
G.H.J. Krüger ◽  
A. Jordaan ◽  
L.R. Tiedt ◽  
R.J. Strasser ◽  
M. Kilbourn Louw ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Conservation ◽  
Root Hairs ◽  
Leaf Tissue ◽  
Severe Drought ◽  
Survival Strategy ◽  
Potted Plants ◽  
New Findings ◽  
Stomatal Apparatus ◽  
Photosynthetic Potential

We present new findings on leaf and stomatal apparatus anatomy and ecophysiology of Welwitschia mirabilis Hook.f. that are relevant to survival in the desert. We show that the structure of the stomatal apparatus with thin areas in the guard cell walls is a key feature enabling an opportunistic survival strategy through reversible quick switch-over from water conservation to CO2assimilation. Desert environment and greenhouse data demonstrated that stomatal conductance increased almost immediately after dawn to reach a maximum within approximately an hour, whereupon a steep decrease occurred. After discontinuation of induced drought in potted plants, fast recovery of stomatal conductance occurred while copious new root hairs developed within 50 h. Stomatal limitation proved to be the main photosynthetic constraint under induced drought. Under severe drought stress, biochemical limitation came into play. Chlorophyll fluorescence data of in-situ plants showed that the photosynthetic potential of leaf tissue is highest near the basal meristem, but although it decreases with age, it retains activity up to the leaf apex at the end of the green part. The photosynthetic potential of potted plants was optimal at 20 °C, analogous to mesophytic plants. Our data confirms our hypothesis that leaf surface and stomatal structure play a crucial role in moisture conservation and moderating leaf temperature for desert survival.

scholarly journals The interactive effects of competition and predation risk on dispersal in an insect

2014 ◽  
Vol 10 (6) ◽  
pp. 20140287 ◽  
Author(s):  
Celina B. Baines ◽  
Shannon J. McCauley ◽  
Locke Rowe
Keyword(s):  
Predation Risk ◽  
Intraspecific Competition ◽  
Aquatic Insects ◽  
Ecological Factors ◽  
Factorial Experiment ◽  
Interactive Effects ◽  
Factorial Experiments ◽  
Evolutionary Processes ◽  
Factors Affecting ◽  
Ecological Conditions

Dispersal dynamics have significant consequences for ecological and evolutionary processes. Previous work has demonstrated that dispersal can be context-dependent. However, factors affecting dispersal are typically considered in isolation, despite the probability that individuals make dispersal decisions in response to multiple, possibly interacting factors. We examined whether two ecological factors, predation risk and intraspecific competition, have interactive effects on dispersal dynamics. We performed a factorial experiment in mesocosms using backswimmers ( Notonecta undulata ), flight-capable, semi-aquatic insects. Emigration rates increased with density, and increased with predation risk at intermediate densities; however, predation had minimal effects on emigration at high and low densities. Our results indicate that factorial experiments may be required to understand dispersal dynamics under realistic ecological conditions.

scholarly journals The interactive effects of enhanced UV-B radiation and soil drought on spring wheat

2007 ◽  
Vol 73 (3) ◽  
pp. 429-434 ◽  
Author(s):  
Huyuan Feng ◽  
Shiwen Li ◽  
Lingui Xue ◽  
Lizhe An ◽  
Xunling Wang
Keyword(s):  
Spring Wheat ◽  
Interactive Effects ◽  
Soil Drought

Water transfer in a mature oak stand (Quercuspetraea): seasonal evolution and effects of a severe drought

1993 ◽  
Vol 23 (6) ◽  
pp. 1136-1143 ◽  
Author(s):  
N. Bréda ◽  
H. Cochard ◽  
E. Dreyer ◽  
A. Granier
Keyword(s):  
Stomatal Conductance ◽  
Potential Evapotranspiration ◽  
Stomatal Closure ◽  
Time Lag ◽  
Xylem Sap ◽  
Water Shortage ◽  
Hydraulic Conductance ◽  
Canopy Conductance ◽  
Severe Drought ◽  
Order Of Magnitude

The reactions of sessile oak (Quercuspetraea (Mattuschka) Liebl.) to drought were studied under natural conditions in a 32-year-old stand near Nancy (northeastern France) during the summers of 1989 (strongly rain deficient) and 1990. A plot of five trees was subjected to imposed water shortage, while a group of irrigated trees was used as a control. Measurements of xylem sap flows and water potential enabled the computation of plot transpiration, canopy conductance, and specific hydraulic conductance in the soil–tree continuum. Stomatal conductance was measured directly with a porometer. Specific hydraulic conductance of our oaks was of the same order of magnitude as that reported for other species. It decreased significantly during spring because of a time lag between cambial growth and leaf area expansion. Measured transpiration was close to potential evapotranspiration, except during days with high vapor pressure deficits, which promoted stomatal closure in the absence of soil water deficits. Imposed drought caused predawn leaf water potentials to reach values as low as −2.0 MPa and a progressive decline in hydraulic conductance, which was probably attributable to modifications in hydraulic properties at the soil–root interface. This gradual decline in conductance was attributed to their deep rooting (1.40 m). This study revealed that Q. petraea may be considered as drought tolerant because of adaptations like deep rooting, efficient and safe xylem sap transport, maintenance of significant stomatal conductance, and significant transpiration, even during strong drought stress.

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