Drought resistance of cotton (Gossypium hirsutum) is promoted by early stomatal closure and leaf shedding

2020 ◽  
Vol 47 (2) ◽  
pp. 91 ◽  
Author(s):  
Ximeng Li ◽  
Renee Smith ◽  
Brendan Choat ◽  
David T. Tissue
Keyword(s):  
Gossypium Hirsutum ◽  
Water Potential ◽  
Drought Resistance ◽  
Leaf Gas Exchange ◽  
Stomatal Closure ◽  
Water Shortage ◽  
Drought Avoidance ◽  
Xylem Vulnerability ◽  
Leaf Shedding

Water relations have been well documented in tree species, but relatively little is known about the hydraulic characteristics of crops. Here, we report on the hydraulic strategy of cotton (Gossypium hirsutum L.). Leaf gas exchange and in vivo embolism formation were monitored simultaneously on plants that were dried down in situ under controlled environment conditions, and xylem vulnerability to embolism of leaves, stems and roots was measured using intact plants. Water potential inducing 50% embolised vessels (P50) in leaves was significantly higher (less negative) than P50 of stems and roots, suggesting that leaves were the most vulnerable organ to embolism. Furthermore, the water potential generating stomatal closure (Pgs) was higher than required to generate embolism formation, and complete stomatal closure always preceded the onset of embolism with declining soil water content. Although protracted drought resulted in massive leaf shedding, stem embolism remained minimal even after ~90% leaf area was lost. Overall, cotton maintained hydraulic integrity during long-term drought stress through early stomatal closure and leaf shedding, thus exhibiting a drought avoidance strategy. Given that water potentials triggering xylem embolism are uncommon under field conditions, cotton is unlikely to experience hydraulic dysfunction except under extreme climates. Results of this study provide physiological evidence for drought resistance in cotton with regard to hydraulics, and may provide guidance in developing irrigation schedules during periods of water shortage.

Leaf Gas Exchange and Water Relations of Lupins and Wheat. II. Root and Shoot Water Relations of Lupin During Drought-Induced Stomatal Closure

1989 ◽  
Vol 16 (5) ◽  
pp. 415 ◽  
Author(s):  
CR Jensen ◽  
IE Henson ◽  
NC Turner
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Transport ◽  
Water Uptake ◽  
Water Relations ◽  
Leaf Gas Exchange ◽  
Stomatal Closure ◽  
Soil Water Potential ◽  
Root Water Uptake ◽  
Leaf Conductance

Plants of Lupinus cosentinii Guss. cv. Eregulla were grown in a sandy soil in large containers in a glasshouse and exposed to drought by withholding water. Under these conditions stomatal closure had previously been shown to be initiated before a significant reduction in leaf water potential was detected. In the experiments reported here, no significant changes were found in water potential or turgor pressure of roots or leaves when a small reduction in soil water potential was induced which led to a 60% reduction in leaf conductance. The decrease in leaf conductance and root water uptake closely paralleled the fraction of roots in wet soil. By applying observed data of soil water and root characteristics, and root water uptake for whole pots in a single-root model, the average water potential at the root surface was calculated. Potential differences for water transport in the soil-plant system, and the resistances to water flow were estimated using the 'Ohm's Law' analogy for water transport. Soil resistance was negligible or minor, whereas the root resistance accounted for 61-72% and the shoot resistance accounted for about 30% of the total resistance. The validity of the measurements and calculations is discussed and the possible role of root- to-shoot communication raised.

scholarly journals Penggulungan daun pada tanaman monokotil saat kekurangan air (Leaf rolling in monocotyledon plants under water deficit)

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Song Ai Nio ◽  
Audry Agatha Lenak
Keyword(s):  
Water Potential ◽  
Water Deficit ◽  
Leaf Water Potential ◽  
Drought Resistance ◽  
Leaf Water ◽  
Leaf Rolling ◽  
Bulliform Cells ◽  
Drought Avoidance ◽  
Evapotranspiration Rate ◽  
Dry Soil

Abstrak Penggulungan daun merupakan salah satu bentuk resistensi terhadap kekeringan atau lebih tepatnya mekanisme menghindari kekeringan pada tumbuhan monokotil. Mekanisme ini terjadi dengan cara menurunkan laju evapotranspirasi atau dengan meningkatkan absorpsi air pada tanah kering untuk mempertahankan potensial air daun tetap tinggi. Proses penggulungan daun ini berkaitan erat dengan peranan sel kipas. Pada saat kekurangan air, jumlah dan ukuran sel kipas meningkat, sehingga daun akan menggulung. Tingkat penggulungan daun dapat ditentukan secara visual berdasarkan sistem standar evaluasi untuk tanaman padi dengan memberi skor 1-9. Rendahnya tingkat penggulungan daun berkorelasi positif dengan meningkatnya potensial air daun. Kata kunci: menghindari kekeringan, penggulungan daun Abstract Leaf rolling is one mechanism of drought resistance, i.e. drought avoidance. This mechanism was resulted from decreasing evapotranspiration rate or increasing water absorption in the dry soil to maintain high leaf water potential. The process of leaf rolling in monocotyledon was closely related to the activity of bulliform cells. The number and size of bulliform cells were increased under water deficit, so that leaf rolling occurred. Leaf rolling score (1-9) could be visually determined based on the system of standard evaluation in rice. The low leaf rolling score was positively correlated with high leaf water potential. Keywords: drought avoidance, leaf rolling

scholarly journals Physiological Mechanisms of Drought Resistance in Four Native Ornamental Perennials

1994 ◽  
Vol 119 (2) ◽  
pp. 299-306 ◽  
Author(s):  
Douglas S. Chapman ◽  
Robert M. Augé
Keyword(s):  
Drought Resistance ◽  
Osmotic Adjustment ◽  
Relative Water Content ◽  
Stomatal Closure ◽  
Echinacea Purpurea ◽  
The Other ◽  
Dehydration Tolerance ◽  
Drought Avoidance ◽  
Relative Water ◽  
Monarda Didyma

Understanding physiological drought resistance mechanisms in ornamentals may help growers and landscapers minimize plant water stress after wholesale production. We characterized the drought resistance of four potted, native, ornamental perennials: purple coneflower [Echinacea purpurea (L.) Moench], orange coneflower [Rudbeckia fulgida var. Sullivantii (Beadle & Boynt.) Cronq.], beebalm (Monarda didyma L.), and swamp sunflower (Helianthus angustifolius L.). We measured a) stomatal conductance of leaves of drying plants, b) lethal water potential and relative water content, and c) leaf osmotic adjustment during the lethal drying period. Maintenance of stomatal opening as leaves dry, low lethal water status values, and ability to osmotically adjust indicate relative drought tolerance, with the reverse indicating drought avoidance. Echinacea purpurea had low leaf water potential (ψL) and relative water content (RWC) at stomatal closure and low lethal ψL and RWC, results indicating high dehydration tolerance, relative to the other three species. Rudbeckia fulgida var. Sullivantii had a similar low ψL at stomatal closure and low lethal ψL and displayed relatively large osmotic adjustment. Monarda didyma had the highest ψL and RWC at stomatal closure and an intermediate lethal ψL, yet displayed a relatively large osmotic adjustment. Helianthus angustifolius became desiccated more rapidly than the other species, despite having a high ψL at stomatal closure; it had a high lethal ψL and displayed very little osmotic adjustment, results indicating relatively low dehydration tolerance. Despite differences in stomatal sensitivity, dehydration tolerance, and osmotic adjustment, all four perennials fall predominantly in the drought-avoidance category, relative to the dehydration tolerance previously reported for a wide range of plant species.

scholarly journals Interaction of stomatal behaviour and vulnerability to xylem cavitation determines the drought response of three temperate tree species

AoB Plants ◽  
2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Zhicheng Chen ◽  
Shirong Liu ◽  
Haibo Lu ◽  
Xianchong Wan
Keyword(s):  
Water Potential ◽  
Tree Species ◽  
Stomatal Closure ◽  
Safety Margin ◽  
Xylem Cavitation ◽  
Stomatal Behaviour ◽  
Xylem Vulnerability ◽  
Humid Region ◽  
Rainfall Reduction ◽  
Lindera Obtusiloba

Abstract How the mortality and growth of tree species vary with the iso-anisohydric continuum and xylem vulnerability is still being debated. We conducted a precipitation reduction experiment to create a mild drought condition in a forest in the Baotianman Mountains, China, a sub-humid region. Three main sub-canopy tree species in this region were examined. After rainfall reduction, Lindera obtusiloba showed severe dieback, but two other co-occurring species did not show dieback. The water potential at stomatal closure of Dendrobenthamia japonica, L. obtusiloba and Sorbus alnifolia was −1.70, −2.54 and −3.41 MPa, respectively, whereas the water potential at 88 % loss in hydraulic conductivity of the three species was −2.31, −2.11 and −7.01 MPa, respectively. Taken together, near-anisohydric L. obtusiloba with vulnerable xylem was highly susceptible to drought dieback. Anisohydric S. alnifolia had the most negative minimum water potential, and its xylem was the most resistant to cavitation. Isohydric D. japonica conserved water by rapidly closing its stomata. Ultimately, the hydraulic safety margin (HSM) of L. obtusiloba was the smallest among the three species, especially in precipitation-reduced plots. In terms of the stomatal safety margin (SSM), L. obtusiloba was negative, while S. alnifolia and D. japonica were positive. Of the two species without dieback, rainfall reduction decreased growth of D. japonica, but did not influence growth of S. Alnifolia; meanwhile, rainfall reduction led to a decrease of non-structural carbohydrates (NSCs) in D. japonica, but an increase in S. alnifolia. It is concluded that HSM as well as SSM allow interpreting the sensitivity of the three sub-canopy species to drought. The drought-induced dieback of L. obtusiloba is determined by the interaction of stomatal behaviour and xylem vulnerability, and the species could be sensitive to climate change-caused drought although still in sub-humid areas. The isohydric/anisohydric degree is associated with NSCs status and growth of plants.

Water relations and drought resistance of young Pinusbanksiana and P. resinosa plantation trees

1977 ◽  
Vol 7 (1) ◽  
pp. 132-137 ◽  
Author(s):  
J. S. Pereira ◽  
T. T. Kozlowski
Keyword(s):  
Water Potential ◽  
Drought Resistance ◽  
Stomatal Closure ◽  
Growing Season ◽  
Early Morning ◽  
Diffusion Resistance ◽  
Soil Water Depletion ◽  
Water Potentials ◽  
Needle Water Potential ◽  
Better Than

Daytime changes in needle water potential and needle diffusion resistance of young Pinusbanksiana and P. resinosa plantation trees were determined at various times throughout the 1974 growing season in northern Wisconsin. Early in the growing season, early-morning water potential and daytime needle diffusion resistance varied little between the two species. However, midday water potentials generally were higher in P. banksiana than in P. resinosa. As the season progressed, water potentials in the early morning were lower, and they decreased more during the day in P. resinosa than in P. banksiana. In addition, stomata of P. banksiana usually closed earlier in the day. Pinusbanksiana appeared to avoid drought better than P. resinosa because the former maintained a higher needle water potential throughout most of the growing season. This reflected lower transpiration and slower soil water depletion associated with lower leaf area and stomatal closure at higher needle water potential in P. banksiana.

scholarly journals Contrasting Water Use, Stomatal Regulation, Embolism Resistance, and Drought Responses of Two Co-Occurring Mangroves

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1945
Author(s):  
Guo-Feng Jiang ◽  
Timothy J. Brodribb ◽  
Adam B. Roddy ◽  
Jin-Yan Lei ◽  
Huai-Tong Si ◽  
...  
Keyword(s):  
Water Potential ◽  
Saline Water ◽  
Stomatal Closure ◽  
Avicennia Marina ◽  
Cavitation Resistance ◽  
Bruguiera Gymnorrhiza ◽  
Drought Avoidance ◽  
Tolerance Strategy ◽  
Safety Margins ◽  
The Difference

The physiological mechanisms underlying drought responses are poorly documented in mangroves, which experience nearly constant exposure to saline water. We measured gas exchange, foliar abscisic acid (ABA) concentration, and vulnerability to embolism in a soil water-withholding experiment of two co-occurring mangroves, Avicennia marina (Forsskål) Vierhapper (Verbenaceae) and Bruguiera gymnorrhiza (L.) Savigny (Rhizophoraceae). A. marina showed higher photosynthesis and transpiration than B. gymnorrhiza under well-watered conditions. Cavitation resistance differed significantly between species, with 50% cavitation occurring at a water potential (P50) of −8.30 MPa for A. marina and −2.83 MPa for B. gymnorrhiza. This large difference in cavitation resistance was associated with differences in stomatal closure and leaf wilting. The rapid stomatal closure of B. gymnorrhiza was correlated with ABA accumulation as water potential declined. Meanwhile, stomatal closure and declining water potentials in A. marina were not associated with ABA accumulation. The safety margins, calculated as the difference between stomatal closure and embolism spread, differed between these two species (1.59 MPa for A. marina vs. 0.52 MPa for B. gymnorrhiza). Therefore, A. marina adopts a drought tolerance strategy with high cavitation resistance, while B. gymnorrhiza uses a drought avoidance-like strategy with ABA-related sensitive stomatal control to protect its vulnerable xylem.

Leaf Gas Exchange and Water Relations of Lupins and Wheat. III. Abscisic Acid and Drought-Induced Stomatal Closure

1989 ◽  
Vol 16 (5) ◽  
pp. 429 ◽  
Author(s):  
IE Henson ◽  
CR Jensen ◽  
NC Turner
Keyword(s):  
Abscisic Acid ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Stomatal Closure ◽  
Triticum Aestivum L ◽  
Leaf Water ◽  
Stomatal Response ◽  
Leaf Water Status

Changes in the content of endogenous abscisic acid (ABA) were followed in glasshouse experiments during stomatal closure induced by drought in leaves of lupin (Lupinus cosentinii Guss. cv. Eregulla) and wheat (Triticum aestivum L. cvv. Gamenya and Warigal), species which differ in stomatal sensitivity to changes in leaf water potential. Increases in bulk leaf ABA concentration were closely correlated with decreases in leaf conductance in both species. In lupin, substantial increases in ABA and decreases in conductance occurred over a very narrow range of leaf water potential. ABA concentrations in wheat leaves were highly negatively correlated with bulk leaf turgor, but there was no significant relationship between ABA and turgor in lupin. However, ABA accumulated progressively in the leaves of both species as soil water content decreased. Stomatal closure in lupin could be induced by supplying exogenous ABA to detached leaves via the transpiration stream at concentrations of 10-4 to 10-2 mol m-3 of (+)-ABA. Abaxial stomata closed more readily than those on the adaxial surface in response to both drought and applied ABA. Stomatal response to ABA was not affected by the presence of the cytokinin zeatin, and zeatin by itself had no effect on conductance. When treatments designed to reduce endogenous cytokinin concentrations were imposed (prolonged leaf detachment or prior drought), stomatal response to low concentrations of ABA was enhanced. However, such treatments did not significantly change the stomatal response to high ABA concentrations, nor affect the stomatal conductance of leaves supplied with water alone. It is concluded that drought-induced stomatal closure could be mediated by ABA in both wheat and lupin, despite the initially small change in leaf water status in the latter species.

Photosynthesis, transpiration, and leaf diffusive conductance of the cassava leaf in response to water stress

1983 ◽  
Vol 61 (1) ◽  
pp. 373-376 ◽  
Author(s):  
Jairo A. Palta
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Stomatal Closure ◽  
Net Photosynthesis ◽  
Water Shortage ◽  
Leaf Water ◽  
Manihot Esculenta Crantz ◽  
Water Potential Measurements ◽  
Response To Water ◽  
Made In

The effects of short periods of water shortage on the CO2 and water vapour exchange of attached cassava (Manihot esculenta Crantz 'M Col 72') leaves were measured. Gas-exchange and leaf water potential measurements were made in outdoor grown plants previously subjected to varying periods without water. Leaf water potentials fell to between −0.61 and −1.06 MPa and net photosynthesis and transpiration rates declined as leaf water potential decreased. Estimations of the leaf internal CO2 conductance indicated that the linear relationship established between leaf water potential and net photosynthesis is dominated by, but not completely explained by, stomatal closure.

The Effect of Water Shortage on Potted Peach Trees in Relation to Ecophysiological Parameters and Infra-red Thermometry

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 541b-541
Author(s):  
Rita Giuliani ◽  
James A. Flore
Keyword(s):  
Chlorophyll Fluorescence ◽  
Gas Exchange ◽  
Early Detection ◽  
Water Potential ◽  
Canopy Temperature ◽  
Water Shortage ◽  
Development Rate ◽  
Plant Water ◽  
Infra Red ◽  
Peach Trees

Potted peach trees grown outdoors during the 1997 season were subjected to drought and subsequent rewatering to evaluate their dynamic response to soil water content. The investigation was primarily focused on the early detection of plant water stress to prevent negative effects on the growth. Leaf chlorophyll fluorescence and canopy temperature estimates (by infra-red thermometry) were conducted. Drought effect on physiological processes were detected through by estimates of canopy development rate, leaf gas-exchange measurements; while leaf water potential was measured to characterize plant water status. A decrease in the canopy's development rate was found 1 week after irrigation was stopped, which also coincided with a more-negative leaf water potential, whereas a decrease of the gas-exchange activities occurred several days later. No significant differences between the stressed and control plants were recorded by the chlorophyll fluorescence parameters (Fo, Fm, Fv and the ratio Fv/Fm), whereas the infra-red estimates of canopy temperature detected a slight increase of the canopy surface temperature (connected to the change of leaf energy balance and in relation to partial stomatal closure) on the non-irrigated plants 1 week after the beginning of the trial. The use of infra-red thermometry for early detection of water shortage is discussed.

scholarly journals Arabidopsis MADS-box factor AGL16 negatively regulates drought resistance via stomatal density and stomatal movement

2020 ◽  
Vol 71 (19) ◽  
pp. 6092-6106 ◽  
Author(s):  
Ping-Xia Zhao ◽  
Zi-Qing Miao ◽  
Jing Zhang ◽  
Si-Yan Chen ◽  
Qian-Qian Liu ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Resistance ◽  
Molecular Mechanisms ◽  
Stomatal Density ◽  
Stomatal Closure ◽  
Negative Regulator ◽  
Stomatal Development ◽  
Mads Box ◽  
Mobility Shift ◽  
Aba Metabolism

Abstract Drought is one of the most important environmental factors limiting plant growth and productivity. The molecular mechanisms underlying plant drought resistance are complex and not yet fully understood. Here, we show that the Arabidopsis MADS-box transcription factor AGL16 acts as a negative regulator in drought resistance by regulating stomatal density and movement. Loss-of-AGL16 mutants were more resistant to drought stress and had higher relative water content, which was attributed to lower leaf stomatal density and more sensitive stomatal closure due to higher leaf ABA levels compared with the wild type. AGL16-overexpressing lines displayed the opposite phenotypes. AGL16 is preferentially expressed in guard cells and down-regulated in response to drought stress. The expression of CYP707A3 and AAO3 in ABA metabolism and SDD1 in stomatal development was altered in agl16 and overexpression lines, making them potential targets of AGL16. Using chromatin immunoprecipitation, transient transactivation, yeast one-hybrid, and electrophoretic mobility shift assays, we demonstrated that AGL16 was able to bind the CArG motifs in the promoters of the CYP707A3, AAO3, and SDD1 and regulate their transcription, leading to altered leaf stomatal density and ABA levels. Taking our findings together, AGL16 acts as a negative regulator of drought resistance by modulating leaf stomatal density and ABA accumulation.

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