Effects of temperature and relative humidity on growth and calcium uptake, translocation, and accumulation in sorghum1

Abstract

Abstract Differences in temperature or relative humidity may partially explain some of the visual appearances of calcium (Ca) deficiency disorders found in sorghum [ Sorghum bicolor (L.) Moench] plants grown in controlled conditions. Independent temperature and relative humidity (R.H.) experiments were conducted using ‘Redlan’ and ‘Martin’ sorghum genotypes grown in three identical growth chambers with temperature treatments of 21/16, 28/23, and 35/30°C or R.H. regimes of 30, 60, and 90% at nutrient solution Ca levels of 25, 50, and 300 mg Ca L‐1. Calcium deficiency symptoms appeared on plants grown with the lowest Ca level at each temperature or R.H. Symptoms became progressively more severe as the temperature increased and were most severe at 60% R.H. The severity of deficiency was higher in Redlan than Martin in the R.H. experiment, but no differences between genotypes appeared with changing temperatures. Plant dry matter and Ca concentrations in plants increased with increasing Ca levels. Lower leaves...