Plant Measurements as Indicators of Crop Water Deficit¹

Abstract

An irrigation experiment was conducted with southern peas [Vigna sinensis L. (Endl.) var. ‘Burgundy’] utilizing lysimeters in which the soil water balance could be controlled. The purpose of the experiment was to compare certain plant measurements as indicators of crop water deficit. Plant measurements made on stressed and non‐stressed plants throughout the growing season were leaf‐water potential, leaf‐air temperature differential, and leaf‐diffusion resistance.Leaf‐water potentials were measured by the pressure chamber method on well‐exposed leaves. Leaf temperatures were measured by infrared radiometry and a diffusion porometer was used to measure leaf‐diffusion resistance. Tensiometers were used to determine the soilwater potential and to time the irrigations.The plant response data taken throughout a day were sensitive to water deficits during the late vegetative stage; however, the measurements were less responsive when the leaves aged, indicated by plants in the pod development stage. The change was particularly evident in the leaf‐water potential measurements. All three plant measurements did indicate water deficit to some degree. Leaf‐diffusion resistance was the least responsive, and leaf‐water potential was the most responsive. Results relating leaf‐water potential to leaf‐diffusion resistance and soilwater potential are also given.

Simulating sunflower canopy temperatures to infer root-zone soil water potential

“…The present model thus supports Clark and Hiler (1973) in t showing that leaf water potential should be more responsive to changes in soil water potential than is canopy-air temperature differential. Remote sensing technology cannot be applied directly to sample leaf water potential.…”

“…By comparing observed leaf water potential, stomatal resiztance, and leaf-air temperature differential of well-watered and water-stressed peas, Clark and Hiler (1973) concluded that leaf water potential was the parameter most sensitive to changes in soil water status. However, leaf water potential, like canopy temperature, is strongly affected by atmospheric variables (Choudhury and Federer, 1983); and this variability can be shown quite easily, since from egns.…”

Use of Chlorophyll Fluorescence Assessments to Differentiate Corn Hybrid Response To Variable Water Conditions

“…Leaf temperatures acquired simultaneously with CF measurements (via the thermocouple attached to the leaf measurement clip) were used to determine the impact of water treatments on plant stress. Leaf temperature is considered to be a proven indicator of plant water stress (Tanner 1963; Clark and Hiler, 1973; Ehrler et al, 1978; Sumayao and Kanemasu, 1979; Jackson et al, 1981; Raskin and Ladyman, 1988), and is based on the principle that increasing plant water deficits lead to stomatal closure, decreased leaf transpirational cooling, and consequently increased leaf temperature relative to well‐watered plants. The ANOVA (Table 2) for leaf temperature revealed a significant water treatment × date interaction, which is illustrated in Fig.…”

“…Clark and Hiler, 1973;Ehrler Reproduced from Crop Science. Published by Crop Science Society of America.…”

Influência de diferentes níveis de sombreamento no comportamento fisiológico de cultivares de café(Coffea arabica L.)

“…A interação entre a demanda evaporativa da atmosfera, potencial de água no solo, distribuição do sistema radicular e processos fisiológicos revela o estado energético de água na planta (Clark & Hiler, 1973), e a expansão foliar, abertura estomática e outros processos associados à fotossíntese são diretamente afetados pela redução do potencial de turgescência da folha, pois a capacidade da planta em manter a turgescência foliar é uma grande adaptação ao déficit hídrico (Jones & Turner, 1978).…”