全生育期模拟覆盖旱作水稻的生理反应

Physiological Responses to Rice Plant under Upland Farming with Mulching

为寻求合理调控旱作栽培水稻生长发育的理论依据,采用土培试验研究比较了覆盖旱作水稻与传统淹水栽培水稻生理变化的差异.结果表明,水稻旱作后苗期根系活跃,吸收面积增加,叶片叶绿素a,b含量及其总量均显著增加,但两者比值不变,根系和叶片硝酸还原酶及硝态氮明显增加,光合速率显著降低.进入抽穗期后,旱作水稻叶片叶绿素a,b含量及其总量仍显著高于淹水处理,且两者比值比淹水处理低0.12,根系和叶片硝酸还原酶及硝态氮仍高于相应淹水处理,特别是旱作水稻根系累积大量硝态氮,光合速率接近.水稻旱作后内源激素变化显著,与淹水处理比较,旱作水稻孕穗期叶片ABA,根系ABA和根系GA1/3显著增加,叶片GA1/3,叶片iPA和根系iPA显著减少,叶片IAA略有增加,而汕优63根系IAA显著增加,85-15根系IAA显著减少.进入乳熟期,叶片IAA,根系iPA和叶片GA1/3显著增加,叶片ABA和根系ABA均不同程度减少,根系GA1/3,根系IAA,叶片iPA的变化因品种不同而明显不同.

Pot experiments are conducted to distinguish nitrogen nutrition characters of rice and adaptation to continuous water stress with the two main treatments: waterlogged soil condition and upland soil condition either by covering straw or film. Compared with rice on waterlogged soil condition, dry matter ratios of root to shoot, leaf length, maximum root length, average root length, and root dry matter weight decrease, with a considerable increase, white root number and ratios of white root number to total root number, however. In addition, quantities of thin roots and root hairs are found from the roots of rice in upland farming. Compared with rice on waterlogged soil condition, the active absorption areas of roots, the activity of glycolic acid oxidase in leaves, the contents of chlorophyll a, b and a+b, the contents of NRA and NO3N both in leaves and roots increase significantly during nursery seedling stages in upland farming. Net photosynthesis rate diminishes obviously while ratios of chlorophyll a to b have little changes. From the youngpanicle differentiation to heading stages, NRA, NO3N, chlorophyll a, b and total content of rice plant maintaine higher levels, whereas ratios of chlorophyll a to b decrease by 0.12 units. Net photosynthesis rate tends to be the same as those in waterlogged soil condition. Endogenous hormone of rice has greater changes in upland farming than in waterlogged cultivation. ABA both in roots and in leaves and GA1/3 in roots of rice cultivated in upland soil increase obviously at the youngpanicle differentiation stage, whereas GA1/3 and iPA in leaves and iPA in roots of rice cultivated in upland soil diminishe significantly. IAA in roots of hybrid rice, Shanyou 63, increase to a great extent, but the reverse is true for upland rice 8515. At the maturing stages of rice,IAA and GA1/3 in leaves, iPA in roots increase significantly while ABA in roots and in leaves decreases to some extent. There are significant differences in GA1/3 and IAA in roots and iPA in leaves among the varieties tested.