The effect of altering nitrogen and sulfur supply on the growth of cut chrysanthemums.

摘要

Dark Yellow Fuji Mefo chrysanthemums were grown hydroponically with 64, 127 or 254 mg N/litre and 0, 1, 2, 4, 8, 16, 32 or 64 mg S/litre in a randomized complete block. Time to flower was measured and symptoms of S deficiency were observed on root,stem and leaf systems. New leaves and inflorescences were analysed for S, and lower leaves were analysed for N concentration. There were 4 sampling dates and 2 experiments. Flower diameter was measured when flowers were present, while stem length was measured every sampling date. N application could be reduced by half to 127 mg/litre as long as some S (4 mg/litre in the autumn and 8 mg/litre in the spring) was applied. S deficiency symptoms observed included branchless roots, which aged earlier, overallyellowing of new leaves and reddening on the leaf abaxial surface starting from older leaves and moving acropetally. Plants receiving no S had smaller leaves, shorter stems, delayed inflorescence initiation and restricted inflorescence development compared with those receiving S. Without S, plants did not produce flowers suitable for commercial sale.