Plant water relations as selection criteria for drought tolerance in mustard

Drought stress encumbers the growth of turfgrass principally by disrupting the plant-water relations and physiological functions. The present study was carried out to appraise the role of silicon (Si) in improving the drought tolerance in Kentucky bluegrass (Poa pratensisL.). Drought stress and four levels (0, 200, 400, and 800 mg L−1) of Si (Na2SiO3·9H2O) were imposed after 2 months old plants cultured under glasshouse conditions. Drought stress was found to decrease the photosynthesis, transpiration rate, stomatal conductance, leaf water content, relative growth rate, water use efficiency, and turf quality, but to increase in the root/shoot and leaf carbon/nitrogen ratio. Such physiological interferences, disturbances in plant water relations, and visually noticeable growth reductions in Kentucky bluegrass were significantly alleviated by the addition of Si after drought stress. For example, Si application at 400 mg L−1significantly increased the net photosynthesis by 44%, leaf water contents by 33%, leaf green color by 42%, and turf quality by 44% after 20 days of drought stress. Si application proved beneficial in improving the performance of Kentucky bluegrass in the present study suggesting that manipulation of endogenous Si through genetic or biotechnological means may result in the development of drought resistance in grasses.

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Drought tolerance versus drought avoidance: A comparison of plant-water relations in herbaceous wetland plants subjected to water withdrawal and repletion

Wetlands ◽

10.1672/0277-5212(2007)27[656:dtvdaa]2.0.co;2 ◽

2007 ◽

Vol 27 (3) ◽

pp. 656-667 ◽

Cited By ~ 47

Author(s):

Brant W. Touchette ◽

Laura R. Iannacone ◽

Gwendolyn E. Turner ◽

Adam R. Frank

Keyword(s):

Drought Tolerance ◽

Water Relations ◽

Wetland Plants ◽

Water Withdrawal ◽

Plant Water Relations ◽

Plant Water ◽

Drought Avoidance

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Plant carbohydrate depletion spreads via ectomycorrhizal networks impairing plant water relations

10.1101/2020.08.03.234823 ◽

2020 ◽

Author(s):

Gerard Sapes ◽

Patrick Demaree ◽

Ylva Lekberg ◽

Anna Sala

Keyword(s):

Drought Tolerance ◽

Water Relations ◽

Pinus Ponderosa ◽

Carbon Allocation ◽

Ecological Impacts ◽

Water Retention Capacity ◽

Plant Water Relations ◽

Clear Understanding ◽

Plant Water ◽

Fungal Interactions

AbstractCarbon and water relations are fundamental to plant life and strongly interact. Under drought, the ability of plants to assimilate carbon is reduced, which increases their consumption of stored labile carbon in the form of non-structural carbohydrates (NSC). This process may impair plant water relations, but mechanisms are not clear, and we do not know if their effects are independent of water deficit. If so, carbon costs of fungal symbionts could also indirectly influence drought tolerance of plants through stored NSC depletion. We connected well-watered Pinus ponderosa seedling pairs via ectomycorrhizal (EM) networks where one seedling was shaded and the other experienced full light and compared responses to seedling pairs in the light. We measured plant water relations and traced carbon movements using 13CO2 to explore the mechanisms linking stored NSC to water relations, and to identify potential tradeoffs between drought tolerance and maintaining EM fungi under carbon-limiting conditions. We found that even in the absence of drought, mild NSC depletion decreased plant drought tolerance by indirectly impairing osmoregulation capacity and turgor maintenance. This demonstrates that NSC storage influences plant drought tolerance independently of plant water status. We also found that EM networks propagated NSC depletion and its negative effects on drought tolerance from carbon stressed hosts to non-stressed hosts. These results highlight carbon allocation tradeoffs between supporting fungal symbionts and retaining water via stored NSC and have implications for biotic interactions and forest drought responses.Significance StatementThe potential effects of future drought on global carbon cycles, vegetation-climate feedbacks, species distributions and their ecological impacts, urgently call for a clear understanding of factors influencing vegetation tolerance to drought. Key to this is the understanding of mechanisms and processes by which plants tolerate drought and how prevalent plant-fungal interactions may influence these processes.We demonstrate that even mild depletion of plant non-structural carbohydrate (NSC) storage readily decreases plant water retention capacity, therefore decreasing tolerance to drought. Because plant-fungal interactions depend on NSC exchange, plants face carbon-allocation tradeoffs between maintaining drought tolerance and feeding fungal symbionts. The impacts of these tradeoffs extend across plants connected via ectomycorrhizal networks as fungi propagate NSC depletion from NSC-limited plants to non-stressed individuals.

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