【作者】 梁国斌；

【导师】 王忠；

【作者基本信息】 扬州大学 ， 植物学， 2002， 硕士

【摘要】 通过盆栽试验对两水稻品种扬稻六号和粳稻941进行不同施氮时期和施氮量的处理，以研究不同施氮处理对水稻植株生长、颖果发育和稻米品质的影响。其主要结果如下： (1)提高分蘖期施氮量能增加水稻植株的鲜重和干重、分蘖数和株高，增加穗肥施氮量能显著提高抽穗期水稻叶片光合速率。 (2)增加穗肥施氮量，胚乳游离核数目增多，分裂周期缩短；同一施氮处理下，籼稻较粳稻胚乳游离核分裂数目多，分裂周期短。 (3)灌浆期颖果叶绿素含量、光合速率、呼吸速率、CAT和SOD活性及颖壳叶绿素含量呈逐渐减小的变化趋势；增加穗肥施氮量能显著提高颖果叶绿素含量、颖果光合速率、呼吸速率、颖果CAT及SOD活性和颖壳叶绿素含量。 (4)颖果中直链淀粉含量随籽粒灌浆天数的增加而逐渐上升；增加穗肥施氮量能显著降低颖果中直链淀粉含量；颖果中蛋白质含量随灌浆天数的增加而逐渐下降，增加穗肥施氮量能显著提高颖果中蛋白质含量。 (5)籽粒灌浆期颖果的鲜重和干重都呈逐渐上升后趋于平缓的变化趋势，含水率先下降，后趋于平缓；不同施氮处理对水稻颖果鲜重、干重和含水率均没有显著影响。 (6)增加穗肥施氮量对颖果中蛋白体、淀粉体发育和糊粉层的形成均有显著的影响。 (7)增加穗肥施氮量对稻米品质有改善作用，即能提高籽粒糙米率、精米率、整精米率、蛋白质含量以及降低稻米垩白和直链淀粉含量等。更多还原

【Abstract】 Pot experiments were conducted to study the effects of various nitrogen treatments on rice seedlings’ growth, caryopses development and ripening grains qualities by two commonly grown rice cultivars. The main results are the following:(1) The increased nitrogen fertilizer (urea) used at the tillering stage can significantly enhance the fresh and dry weights, tillering numbers and heights of rice seedlings. The same is true for the photosynthetic rate of the rice flag leaf when topdressing was used at the heading stage.(2) Increasing the nitrogen fertilizer, especially at the heading stage, can evidently increase the numbers of free nuclei in endosperm and shorten the division cycle. At the same nitrogen treatment level, compared with Japonica, there are more free nuclei in Indica and the contrary is true for the division cycle.(3) The chlorophyll content, photosynthetic rate, and activities of CAT and SOD in caryopses decrease gradually during the rice grain filling. The topdressing ratio of nitrogen fertilizer at the heading stage is positively correlated to the physiological factors mentioned above.(4) The amylose content in the caryopses decreases gradually during the rice grain filling and the contrary is true for the protein content. Topdressing ratio of nitrogen fertilizer at the heading stage is markedly positively and negatively correlated with the amylose and protein content respectively in caryopses.(5) The fresh and dry weights of caryopses increase significantly after anthesis, 5-15d for Indica and 5~20d for Japonica, showing the curve of "S" shape, while the contrary is true for water content in caryopses. The nitrogen fertilizer treatments had no significant effect on the fresh and dry weights of the caryopses.(6) Increased topdressing of nitrogen fertilizer at the heading stage had significant effect on the development of protein bodies and amyloplasts, and the formation ofaleurone layer in caryopses.(7) Increased topdressing of nitrogen fertilizer at the heading stage can markedly improve the rice grain qualities. That is, the nitrogen fertilizer raised the ratios of brown, fine and integrated fine rice grains and increased protein content compared with the control group, while decreased the degree of opaqueness and amylose content.更多还原