In the wake of declining water availability for agricultural use that will severely disturb the cultivation of irrigated lowland rice (Oryza sativa), aerobic genotypes have been developed allowing rice to grow under drier conditions. However, canopy physiological and morphological characteristics associated with adaptation of aerobic rice to water-limited conditions have so far been understudied. Canopy architectural characters, light and nitrogen distribution parameters (i.e. the extinction coefficient for light, K_L; and for nitrogen, K_N; and their ratio K_N:K_L), plant growth and yield were examined in irrigated-lowland (cv. IR64) vs aerobic (cv. Apo) rice genotypes grown under three water regimes. Compared with cv. IR64, cv. Apo allocated less nitrogen to strongly shaded leaves, allowing the vertical nitrogen distribution to better acclimate to light distribution within the canopy. The K_N:K_L ratio increased with increasing water deficit, and cv. Apo (up to 49 % increase) had a higher increase than cv. IR64 (up to 24 % increase). This was attributed to the maintenance of erect leaves at the upper part of the canopy, allocation of less leaf area and less nitrogen to the shaded leaves under water deficit in cv. Apo. The observed differential response in the K_N:K_L ratio partly explained the difference in biomass gain and yield in response to water deficit between the two rice cultivars. We concluded that favourable above-ground architecture and canopy nitrogen profile relative to the light profile contributed greatly to the better performance of cv. Apo than cv. IR64 under dry conditions.

在农业用水减少将严重干扰灌溉低地水稻（Oryza sativa）的种植之后，已经开发出好氧基因型，使水稻能够在更干燥的条件下生长。然而，迄今为止，与需氧水稻适应缺水条件相关的冠层生理和形态特征尚未得到充分研究。冠层建筑特征、光和氮分布参数（即光的消光系数K _L；氮的消光系数K _N；以及它们的比率K _N : K _L)，在灌溉低地 (cv. IR64) 与需氧 (cv. Apo) 水稻基因型中检查了植物生长和产量，这些水稻基因型在三种水条件下生长。与简历相比。IR64，简历。Apo 将较少的氮分配给强烈遮荫的叶子，使垂直氮分布更好地适应树冠内的光分布。所述ķ _Ñ：ķ_大号比例与水赤字增加，和CV增加。Apo（最多增加 49%）比 cv 有更高的增加。IR64（最多增加 24%）。这归因于在树冠上部保持直立的叶子，在 cv. 中水分不足的情况下，分配给阴影叶的叶面积和氮较少。载脂蛋白。在K _{N 中}观察到的微分响应：K_L比率部分解释了两个水稻品种之间响应水分亏缺的生物量增益和产量差异。我们得出结论，有利的地上结构和相对于光剖面的冠层氮剖面对 cv. 的更好性能做出了很大贡献。载脂蛋白比cv。IR64 在干燥条件下。