PHOTOSYNTHETIC RATE AND MESOPHYLL SURFACE AREA IN EXPANDING LEAVES OF ALTERNANTHERA PHILOXEROIDES GROWN AT TWO LIGHT LEVELS
PHOTOSYNTHETIC RATE AND MESOPHYLL SURFACE AREA IN EXPANDING LEAVES OF ALTERNANTHERA PHILOXEROIDES GROWN AT TWO LIGHT LEVELS
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DOI：
10.1002/j.1537-2197.1985.tb05340.x
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发表时间：
1985
影响因子：
3
通讯作者：
D. Longstreth;J. Bolaños;R. Goddard
中科院分区：
文献类型：
--
作者：
D. Longstreth;J. Bolaños;R. Goddard
空心莲子草（Alternanthera philoxeroides）的叶子，在光合光子通量密度（PPFD，波长为 400 至 700 nm 的光能）为 790 umol sec-' m-2（高光）下发育时，其表面积更小，更厚，具有更高的最大 Pn（CO2 吸收净速率），并且与在160，umol sec-' m-2（低光）。低光条件下，出苗后 2 天叶肉厚度在最大值的 19% 以内，但在高光条件下，叶肉厚度在叶片出苗后 2 至 16 天内增加了 79%。在两种光照处理的发育过程中，叶肉表面积与叶片表面积之比均下降；然而，在完全展开的高光叶子中，该比率比在低光叶子中高出 70% 以上。以叶片表面积为基础表示的最大 Pn 在高光叶片中比在低光叶片中高出 158%，但在以叶肉表面积为基础表示时 Pn 仅高出 58%。当在 PPFD 叶子展开时测量 Pn 时，估计完全展开的高光叶子比完全展开的低光叶子固定每片叶子多 72% 的 CO2（Pn 表示每单位表面积乘以每片叶子的总表面积）。当 Pn 在 160 umol sec-' m-2 下测量时，高光和低光叶子每片叶子固定的 CO2 量大约相同，因为低光叶子的较大表面积抵消了 Pn 的微小差异
Leaves of Alternanthera philoxeroides, alligator weed, developed at a photosynthetic photon flux density (PPFD, light energy at wavelengths of 400 to 700 nm) of 790 ,umol sec-' m-2 (High Light) had less surface area, were thicker, had a higher maximum Pn (net rate of CO2 uptake), and required a higher PPFD for saturation of PnX than leaves developed at 160 ,umol sec-' m-2 (Low Light). Mesophyll thickness at Low Light was within 19% of maximum 2 days after emergence but at High Light, thickness increased 79% between 2 and 16 days after leafemergence. The ratio of mesophyll surface area to leaf surface area decreased during development in both light treatments; the ratio, however, was over 70% greater in fully expanded High Light leaves than in Low Light leaves. Maximum Pn expressed on a leaf surface area basis was 158% greater in High Light leaves than in Low Light leaves, but Pn was only 58% greater when expressed on a mesophyll surface area basis. It was estimated that fully expanded High Light leaves fixed 72% more CO2 per leaf (Pn expressed per unit surface area times the total surface area per leaf) than fully expanded Low Light leaves when Pn was measured at the PPFD leaves expanded under. Both High and Low Light leaves would fix about the same amount of CO2 per leaf when Pn was measured at 160 ,umol sec-' m-2 because the larger surface area of the Low Light leaves offset small differences in Pn