Effects of iron availability on physiology of Chinese broccoli (Brassica alboglabrd) at different root-zone temperatures

摘要

Chinese broccoli (B. alboglabrd), a subtropical plant, was first grown at 25°C root-zone temperature (RZT) while its aerial portions were exposed to the hot, fluctuating temperatures for 4 weeks in the tropical greenhouse. Interaction between iron (Fe) availability and RZT were then studied by exposing the roots of aeroponically-grown plants to two different RZTs: a constant 25°C-RZT and a fluctuating ambient RZT (A-RZT). There were three different Fe levels [full Fe (F-Fe), V4-Fe and 0-Fe] in thenutrient medium supplied to plants at each RZT. The results indicated that the impact of Fe availability on growth and physiology of Chinese broccoli was greater than that caused by hot A-RZT, although hot A-RZT may mask the effects of Fe deficiency on these plants.