The influences of environmental diversity on water-use efficiency, carbon isotope discrimination, leaf movements and nutrition of bush bean

Effects of growth environment (E) on carbon isotope discrimination (Δ), water-use efficiency (WUE), leaf movement (LM) and nutrition of bush bean were examined. Environments in greenhouse (GR), open air (E₀), perforated (E₁) and non-perforated (E₂) plastic covers in combination with well-watered (W₀), moderately-watered (W ₁), and water-stressed (W₂) plants were used. Soil water content (WC), E, and E x WC interaction significantly affected Δ, WUE, dry matter (DM) and water use. WUE, photosynthetic rate, and leaf nitrogen increased; while Δ, DM, and transpiration decreased with water stress in GR, and E₀. WUE in E₂ either decreased or remained almost constant with decrease of WC. WUE of W₀, and Δ in E₂ were independent of growing environment, and WC, respectively. WUE and Δ correlations were significant in GR, E₀, and E ₁. LM was more paraheliotropic inside plastic coverings than those in E₀. LM and pulvinus water content were affected by WC and temperature. High correlations were found between LM and the transmission of beta-rays from a beta-ray gauging system, WC, and leaf water potential. A high correlation was also found between leaf angle and 45Ca activity ratio between the extensor and flexor parts of the pulvinus. 32P uptake increased with increased root temperature, and decreased in presence of iron in the medium. Q₁₀ values showed 32P uptake with and without the presence of iron to be mostly diffusion-controlled, but leaf movements were active processes requiring the expenditure of energy.