Visual estimation of plant water status in cereals

1979 ◽  
Vol 92 (1) ◽  
pp. 83-89 ◽  
Author(s):  
H. G. Jones

SummaryThe potential offered for plant breeding programmes by visual scoring techniques for plant water status was investigated in rice and spring wheat. It was found that differing plant morphology could seriously bias visual estimates of leaf water potential, particularly in spring wheat. In spite of this problem, it was found that at least for rice, this type of approach may have potential in future breeding programmes where an estimate of leaf water status is required, such as those for drought tolerance, so long as a high intensity of selection is not necessary.

2019 ◽  
Vol 13 (2) ◽  
pp. 41-54 ◽  
Author(s):  
O. O. Makar ◽  
◽  
O. I. Patsula ◽  
Y. Z. Kavulych ◽  
T. I. Batrashkina ◽  
...  

2021 ◽  
Vol 118 (23) ◽  
pp. e2008276118
Author(s):  
Piyush Jain ◽  
Weizhen Liu ◽  
Siyu Zhu ◽  
Christine Yao-Yun Chang ◽  
Jeff Melkonian ◽  
...  

Leaf water potential is a critical indicator of plant water status, integrating soil moisture status, plant physiology, and environmental conditions. There are few tools for measuring plant water status (water potential) in situ, presenting a critical barrier for developing appropriate phenotyping (measurement) methods for crop development and modeling efforts aimed at understanding water transport in plants. Here, we present the development of an in situ, minimally disruptive hydrogel nanoreporter (AquaDust) for measuring leaf water potential. The gel matrix responds to changes in water potential in its local environment by swelling; the distance between covalently linked dyes changes with the reconfiguration of the polymer, leading to changes in the emission spectrum via Förster Resonance Energy Transfer (FRET). Upon infiltration into leaves, the nanoparticles localize within the apoplastic space in the mesophyll; they do not enter the cytoplasm or the xylem. We characterize the physical basis for AquaDust’s response and demonstrate its function in intact maize (Zea mays L.) leaves as a reporter of leaf water potential. We use AquaDust to measure gradients of water potential along intact, actively transpiring leaves as a function of water status; the localized nature of the reporters allows us to define a hydraulic model that distinguishes resistances inside and outside the xylem. We also present field measurements with AquaDust through a full diurnal cycle to confirm the robustness of the technique and of our model. We conclude that AquaDust offers potential opportunities for high-throughput field measurements and spatially resolved studies of water relations within plant tissues.


1969 ◽  
Vol 22 (2) ◽  
pp. 289 ◽  
Author(s):  
JH Troughton

The effect of plant water status on the diffusion of C02 in the gas and liquid phase in leaves of cotton plants was studied in a single leaf chamber under conditions of constant light level and temperature and when photosynthesis was limited by the CO2 supply. A controlled range of relative leaf water contents from 56 to 96% was obtained by varying root temperature from 6 to 30�C while the tops of the plants were -at a constant temperature. Decreasing water content resulted in an increase in the calculated leaf diffusive resistance and a decrease in CO2 exchange. Under the environmental conditions used, plant water status primarily affects C02 exchange by regulating stomatal aperture. The mesophyll resistance, which was estimated in air and in an oxygen-free atmosphere, did not vary with the relative leaf water content down to 75% but increased progressively as relative water content dropped from 75 to 56%.


2020 ◽  
Author(s):  
Piyush Jain ◽  
Weizhen Liu ◽  
Siyu Zhu ◽  
Jeff Melkonian ◽  
Duke Pauli ◽  
...  

AbstractLeaf water potential is a critical indicator of plant water status, integrating soil moisture status, plant physiology, and environmental conditions. There are few tools for measuring plant water status (water potential) in situ, presenting a critical barrier for the development of appropriate phenotyping (measurement) methods for crop development and modeling efforts aimed at understanding water transport in plants. Here, we present the development of an in situ, minimally-disruptive hydrogel nanoreporter (AquaDust) for measuring leaf water potential. The gel matrix responds to changes in water potential in its local environment by swelling; the distance between covalently linked dyes changes with the reconfiguration of the polymer, leading to changes in the emission spectrum via Fluorescence Resonance Energy Transfer (FRET). Upon infiltration into leaves, the nanoparticles localize within the apoplastic space in the mesophyll; they do not enter the cytoplast or the xylem. We characterize the physical basis for AquaDust’s response and demonstrate its function in intact maize (Zea mays L.) leaves as a reporter of leaf water potential. We use AquaDust to measure gradients of water potential along intact, actively transpiring leaves as a function of water status; the localized nature of the reporters allows us to define a hydraulic model that distinguishes resistances inside and outside the xylem. We also present field measurements with AquaDust through a full diurnal cycle to confirm the robustness of the technique and of our model. We conclude that AquaDust offers potential opportunities for high-throughput, field measurements and spatially resolved studies of water relations within plant tissues.


2010 ◽  
Vol 37 (8) ◽  
pp. 726 ◽  
Author(s):  
Matthew T. Harrison ◽  
Walter M. Kelman ◽  
Andrew D. Moore ◽  
John R. Evans

To model the impact of grazing on the growth of wheat (Triticum aestivum L.), we measured photosynthesis in the field. Grazing may affect photosynthesis as a consequence of changes to leaf water status, nitrogen content per unit leaf area (Na) or photosynthetic enzyme activity. While light-saturated CO2 assimilation rates (Asat) of field-grown wheat were unchanged during grazing, Asat transiently increased by 33–68% compared with ungrazed leaves over a 2- to 4-week period after grazing ended. Grazing reduced leaf mass per unit area, increased stomatal conductance and increased intercellular CO2 concentrations (Ci) by 36–38%, 88–169% and 17–20%, respectively. Grazing did not alter Na. Using a photosynthesis model, we demonstrated that the increase in Asat after grazing required an increase in Rubisco activity of up to 53%, whereas the increase in Ci could only increase Asat by up to 13%. Increased Rubisco activity was associated with a partial alleviation of leaf water stress. We observed a 68% increase in leaf water potential of grazed plants that could be attributed to reduced leaf area index and canopy evaporative demand, as well as to increased rainfall infiltration into soil. The grazing of rain-fed grain cereals may be tailored to relieve plant water stress and enhance leaf photosynthesis.


1974 ◽  
Vol 82 (1) ◽  
pp. 19-27 ◽  
Author(s):  
D. K. Jackson

SUMMARYSimulated swards of Dactylis glomerata (var. S.37) and Lolium perenne (var. S.23) were grown in large lysimeters or vertical pipes of 15 cm diameter, both sufficiently deep to allow largely unrestricted root development.Rainfall was excluded, and the effect of a drying cycle on the plant water balance was compared with irrigated controls in a sequence of sampling harvests at increasing soil water deficits.Leaf water potential (ΨL) fell during the day, both in treatments and controls, to levels which might be expected to reduce extension growth and, frequently, stomatal diffusion. Rapid recovery occurred in the evening to levels which might allow normal functioning of growth processes not dependent on sunlight. Defoliation reduced plant stress and stomatal restriction.The amelioration of plant water stress appeared to require a reduction in atmospheric evaporative demand, and irrigation had relatively little effect. The possibility is discussed that the major benefits of irrigation are other than through the relief of water stress within the plant. The significance of this is considered in relation to conventional irrigation techniques.The leaf water status was more sensitive to drought, transpiration was reduced more, and the root system extended more slowly in Dactylis than in Lolium. Consequently, the onset of permanent wilting due to exhaustion of water from the profile was delayed compared with Lolium. It is deduced that this characteristic might enhance the survival of Dactylis in prolonged drought, but prove disadvantageous in terms of growth during short droughts, when reduced stomatal opening might limit CO2 uptake. This would not be an impediment, however, if investigations suggesting that partial closure has a minor effect on CO2 uptake compared with that on transpiration were to be confirmed.


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