Changes in Photosynthetic Apparatus in the Juvenile Rice Canopy and a Possible Function of Photosystem I in the Bottom Leaves
Changes in Photosynthetic Apparatus in the Juvenile Rice Canopy and a Possible Function of Photosystem I in the Bottom Leaves
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幼稻冠层光合机构的变化及底叶光系统I的可能功能
DOI：
10.1515/znc-1999-1110
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Y. Sugimura
中科院分区：
文献类型：
--
作者：
J. Yamazaki;Y. Kamimura;Y. Sugimura
摘要测定了水稻冠层光系统（PS）Ⅰ和PS Ⅱ的光合机构和相对触角大小的变化。结果表明：（1）叶绿素（Chl）的550 nm电致变色位移和细胞色素E的水平从第6叶到第3叶逐渐降低，但色素（P）-700的损失不明显;因此，PS II/PS I比值从第6片叶的1.5显著降低到第3片叶的0.9。(2)第6叶的电子传递能力是第3叶的1.5倍。(3)细胞色素b6相对于叶绿素的水平从上到下几乎是恒定的。(4)随着深度的增加，叶片的光合性能下降，而呼吸作用略有增加。根据这些结果，我们推测，当光吸收和电子传递能力的不平衡发生在底部叶片时，存在维持机制。
Abstract Changes in the photosynthetic apparatus and relative antenna sizes of photosystem (PS) I and PS II were measured in the rice canopy. We used juvenile rice seedlings to examine light utilization and its absorption in the bottom leaves and obtained the following results: (1) When referred to chlorophyll (Chl), levels of the electrochromic shift at 550 nm and cytochrome ƒ decreased from the sixth to the third leaves, but there was no loss of pigment (P)-700. As a consequence, the PS II/PS I ratio significantly decreased from 1.5 in the sixth leaves to 0.9 in the third leaves. (2) The electron transport capacity in the sixth leaves was 1.5-times larger than that in the third leaves. (3) The levels of cytochrome b6 referred to Chl were almost constant from top to bottom. (4) The photosynthetic performance of the leaf decreased concomitant with the depth, whereas the respiration was slightly increased. From these results, we hypothesize that there are maintenance mechanisms when the imbalances of light absorption and electron transport capacity occur in the bottom leaves.