Abstract: With Shanyou 63 (indica hybrid rice) and 9516 (japonica rice) as materials, reasons of lodging under dry land cultivation (DC) were investigated. Results showed that the lodging percentage under DC was significantly higher than that under traditional flooding cultivation (FC), which made its yield significantly lower than that under FC. The plumpness status (thickness and weight per centimeter), the thickness of cell wall of sclerenchyma and of silicification layer of epidermis, and the content of usable carbohydrate (soluble sugar + starch) of basal internode, plant physiological activities i.e. chlorophyll content of flag leaf, root oxidation activity and the content of cytokinin (zeatin + zeatin riboside) in root, under DC were lower than those under FC. The application of silicon and potassium could not only increase plant physiological activities and the content of usable carbohydrate, raise the thickness of cell wall of sclerenchyma and of silicification layer of epidermis of basal internode, but also improve the plumpness status of basal internode and promote the ability of lodging resistance, and increase the yield eventually. Results were reversed after cutting 1/2 leaves at booting stage. These results suggested that early senescence (low plant physiological activities) affected the plumpness of basal internode and caused the lodging under DC. The lodging mechanism and countermeasure under DC were discussed.

Key words: rice, dry cultivation, lodging, physiological reason, countermeasure

摘要： 以籼型杂交稻汕优63和粳稻9516为材料，研究了旱种水稻倒伏的原因。结果表明：旱种水稻的倒伏率明显高于常规水种水稻，使得产量较水种水稻明显下降。旱种水稻基部节间充实程度(秆壁厚度、单位长度节间重量)、茎秆厚壁组织细胞壁和表皮硅质层厚度、基部节间可用性糖含量及植株的生理活性［剑叶叶绿素含量、根系氧化力、细胞分裂素(玉米素+玉米素核苷)含量］均不及常规水种水稻。施用硅、钾肥能提高旱种水稻植株的生理活性，增加抽穗期和成熟期基部节间可用性糖的贮存，增加茎秆厚壁组织细胞壁及表皮硅质层的厚度，提高茎秆基部节间充实程度，增强抗倒伏能力，最终提高旱种水稻的产量。孕穗期去1/2叶，结果则相反。表明由于旱种水稻早衰(植株生理活性低)，影响了水稻基部节间的充实，造成旱种水稻发生倒伏。还就旱种水稻倒伏机理及对策进行了讨论。

关键词: 水稻, 旱种, 倒伏, 生理原因, 对策