Photosynthesis, Transpiration, and Leaf Elongation in Corn Seedlings at Suboptimal Soil Temperatures¹

Abstract

The physiology of plant response to low soil temperatures is not well understood. Laboratory studies were conducted to examine the relative sensitivities of rates of leaf elongation, net photosynthesis, and transpiration and the leaf water potential of corn seedlings (Zea mays L. ‘Pride 5’) to decreasing temperature. These parameters were simultaneously monitored, as the soil temperature was decreased from 28 to 10 C at about 4 C increments. The different soil temperatures were imposed during a 10‐hour period on 14‐day‐old plants with seven exposed leaves growing at a 27.5 C air temperature, a 55% relative humidity, and a light intensity of 753 μE/m2/sec. Any decrease of the soil temperature below 28 C decreased the leaf elongation rate. This was attributed to restricted water uptake which lowered the plant water potential and to the temperature decrease of the shoot apical meristem region. Leaf elongation ceased at the plant water potential of —9 bars due to decline of leaf turgor pressure. Neither transpiration nor net photosynthesis was reduced significantly until the plant water potential reached —12 to —13 bars. Increases in both stomatal and internal resistances to CO2 diffusion coincided with the decreased net photosynthesis at low plant water potentials. Suboptimal soil temperatures affect corn seedling growth primarily by decreasing leaf elongation.

Growth and physiological trait variation among corn hybrids for cold tolerance

“…This may be due to temperature effects on leaf addition rates and leaf cell elongation processes. The reductions in leaf area in response to low temperatures are in agreement with the reports of Barlow et al (1977). Tollenaar et al (1979) also stated that the minimum temperature for leaf area expansion in corn was 7°C, and the optimum 25°C.…”

Low Root Temperature Effects on Soybean Nitrogen Metabolism and Photosynthesis

“…In such species as Zea mays it appears that photosynthesis, Er, and transpiration rate are controlled by leaf water potential, which is drastically lowered by low soil temperature (1). Our data would suggest that in soybeans this relationship may be much more complicated (Figs.…”

Recovery of maize seedling growth, development and photosynthetic efficiency after initial growth at low temperature

“…A linear dependence between shoot meristem temperature and leaf elongation rate has been observed, but its mechanism is not known (Barlow et al, 1977;Giaufret et al, 1995;Ben-Haj-Salah and Tardieu, 1995;Tardieu, 2003). According to Tardieu (2003) the slope of this relationship is a stable characteristic of a genotype and differs among genotypes.…”