ISHS Acta Horticulturae 403: International Symposium on Cultivar Improvement of Horticultural Crops. Part 2: Fruit Crops
SOME GROWTH AND PHYSIOLOGICAL RESPONSES OF IRON-EFFICIENT AND-INEFFICIENT SPECIES OF MALUS TO IRON DEFICIENCY |
| Authors: | Z. Haihan, T. Shen, F. Rongwu |
| Abstract:
Preliminary experiments have shown that Malus xiaojinensis Cheng et Jiang was iron-efficient, M. baccata (L.) Borkh., iron-inefficient while M. micromalus Makino was intermediate. The experiments reported herein were designed to study some growth and physiological responses of these three species under the condition of iron stress as compared to under that of adequate iron supply. Young seedlings of these three species were grown in culture solutions adjusted to pH 7.8. The results indicated that there was no statistically significant differences in stem and root growth and in the content of mineral elements between iron deficiency and adequate iron supply. The photosynthesis rate of the young top leaves and their chlorophyll content, under adequate iron supply, were highest for M. xiaojinensis, followed by M. micromalus, the lowest being M. baccata. Under iron deficiency, both the photosynthesis rate and chlorophyll content of all these three species decreased during the period of 42 days. Although under adequate iron supply, the ATP content in the root, from high to low, was in the order of M. baccata > M. micromalus > M. xiaojinensis, there occurred a remarkable change under iron stress. In terms of percentage of changes in ATP content, an increase was observed in M. xiaojinensis and M. micromalus and a decrease in M. baccata. The results obtained indicate that root ATP content and P/Fe ratio appear to be reliable criterium in screening for iron-efficient genotypes in the genus Malus. | |
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