Effects of leaf age, nitrogen nutrition and photon flux density on the organization of the photosynthetic apparatus in leaves of a vine (Ipomoea tricolor Cav) grown horizontally to avoid mutual shading of leaves
Effects of leaf age, nitrogen nutrition and photon flux density on the organization of the photosynthetic apparatus in leaves of a vine (Ipomoea tricolor Cav) grown horizontally to avoid mutual shading of leaves
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DOI：
10.1007/bf00197597
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发表时间：
1996-01-01
期刊：
影响因子：
4.3
通讯作者：
Hikosaka, K
中科院分区：
文献类型：
--
作者：
Hikosaka, K
研究了叶片年龄、氮营养和光子通量密度（PFD）对葡萄叶片光合机构组织的影响。水平种植，避免叶片相互遮荫。在两个硝酸盐水平下，在两个生长光处理下进行水培。其中一组植物的叶子暴露在充足的阳光下。对于另一组，各自的叶子被人工遮蔽，以模拟随着直立草本冠层的发展而发生的光梯度变化：随着植物的生长，老叶被放置在逐渐荫蔽的条件下（冠层型遮阳）。在所有处理中，叶绿素含量随叶龄逐渐降低。每Chl的光系统I （PSI）是恒定的，与叶龄、氮营养和/或PFD无关。光系统II （PSII）和细胞色素f / Chi、Chl alb比值与叶龄和/或氮营养无关，但随着生长PFD的降低而降低。每Chi核酮糖-1,5-二磷酸羧化酶（EC 4.1.1.39, RuBPCase）随PFD的降低而急剧下降。在相同PFD条件下生长的叶片比较，低氮有效性条件下生长的植株RuBPCase/Chl较低，无遮荫条件下生长的植株RuBPCase/Chl随叶龄而降低。这种下降与充分日照条件下叶片中RuBPCase与Chi之间的曲线关系有关，与氮有效性和叶龄无关。综上所述，光合机构的组成与叶龄无关，而随光环境和叶片光合成分总量的变化而变化。
Effects of leaf age, nitrogen nutrition and photon flux density (PFD) on the organization of the photosynthetic apparatus in leaves were investigated in a vine, Ipomoea tricolor Cav., which was grown horizontally so as to avoid mutual shading of leaves. The plants were grown hydroponically at two nitrate levels under two growth light treatments. For one group of the plants, leaves were exposed to full sunlight. For another group, respective leaves were artificially shaded in a manner that simulated changes in the light gradient with the development of an erect herbaceous canopy: old leaves were placed under progressively shadier conditions with growth of the plants (canopy-type shading). In all the treatments, chlorophyll (Chi) content gradually decreased with leaf age. Photosystem I (PSI) per Chl was constant, independent of leaf age, nitrogen nutrition and/or PFD. Photosystem II (PSII) and cytochrome f per Chi, and Chl alb ratio were independent of leaf age and/or nitrogen nutrition but decreased with the decrease in growth PFD. Ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39, RuBPCase) per Chi steeply decreased with decrease in PFD. When leaves grown at the same PFD were compared, RuBPCase/Chl was lower in the plants grown under lower nitrogen availability and also decreased with leaf age in the plants grown without shading. These decreases were attributed to the curvilinear relationship between RuBPCase and Chi in leaves grown at full sunlight, that was independent of nitrogen availability and leaf age. From these results, it is concluded that the composition of the photosynthetic apparatus is independent of leaf age but changes depending on the light environment and total amount of photosynthetic components of the leaf.