早稻旱育秧形态、组织结构和生理特性

本文分析了杂交早稻威优４８－２旰育秧和湿润育秧若干形态，组织结构和生理特性差异，讨论了旱育对秧苗根系和根系活力的影响以及南方早稻旱育高产栽培技术的增机制。结果表明：与湿润育秧比较，旱育秧地上部矮壮，分蘖和叶片表皮毛增多，气孔开度增大，叶脉变薄，气腔变小；根系发达，总根数、白根数、根干重、根毛和根系吸收面积增大；根尖和叶肉细胞体积变小，排列更紧密，原生质浓度增高；要系ＰＯＤ和ＰＡＬ活性显著增强；但根

Studies on the Morphology, Tissue Structure and Physiological Characteristics of Early Rice (Oryza sativa L.)Seedlings Raised in Dry Nursery

The differences on morphology, tissue structure and physiological characteristics between rice seedlings raised in dry nursery(RSRDN) and rice seedlings raised in wet nursery (RSRWN)of early hybrid rice Veiyou 48-2 were investigated, and the effects of drought stress on root growth and root vigor, the mechanism of high grain output of rice cultivation technique by raising seedlings in dry nursery in the southern part of China were discussed. Results showed that: Compared with that of RSRWN, the aerial part of RSRDN was shorter and sturdier, and got more tillers, more cuticular hairs, bigger stomas, and smaller leaf veins and air carvities; the root system of RSRDN developed better, with more roots, more white roots, more root hairs, bigger dry weight and absorption area; the root tip cells and the mesophllic cells of RSRDN became smaller and more tightly arranged, with more concentrated protoplasms; the elongation of root tip cells of RSRDN was inhibited and the differentiation of the root tip ventilation tissue of RSRDN was delayed; the root vigor, the nitrogen assimilation ability, the carbon assimillation a-bility, the water retention ability, the new root generation ability, the root POD activity and the root PAL activity of RSRDN were much stronger than those of RSRWN. However, the respiration rate, the COX activity and the ratio of EMP-TCAC pathway activity in total respiration rate of the root system of RSRDN were of 34. 5% , 12. 0% and 2. 3% less than those of the root system of RSRWN respectively. Moreover, the root vigor of RSRDN increased obviously with the leafage advanced from 2.1 to 3.1, and decreased rapidly with the leafage advanced from 3. 1 to 4. 5. While the root vigor of RSRWN still increased a little when its leafage advanced from 3. 1 to 4. 5. All these results suggested that under drought stress conditions RSRDN underwent a series of adaptive changes in its morphology, tissue structure and physiological characteristics.