The influence of water content and leaf anatomy on carbon isotope discrimination and photosynthesis in Sphagnum
The influence of water content and leaf anatomy on carbon isotope discrimination and photosynthesis in Sphagnum
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DOI：
10.1111/j.1365-3040.1996.tb00233.x
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发表时间：
1996-01-01
影响因子：
7.3
通讯作者：
Giles, L
中科院分区：
文献类型：
--
作者：
Rice, SK;Giles, L
研究了泥炭藓（Sphagnum）的水膜扩散阻力（r（wf））和叶片解剖结构（r（p））对净光合速率和碳同位素鉴别（Delta = Delta delta C-13）的相对影响。泥炭藓物种在叶表面的光合细胞暴露方面不同。In S.仿射型光合细胞广泛暴露在表面，而在S.在麦哲伦藻中，光合细胞被包围在充满水的透明细胞内。预计这种差异将导致叶片内扩散阻力（r（p））的变化。净光合作用和在线三角洲测定两种水分含量：温室水分含量（湿）和吸干（干）。在不校正呼吸作用的情况下，湿（千分之23.7）和干（千分之30.9）植物之间的在线Delta值差异显着。然而，物种之间的平均值没有显着差异，没有物种x含水量的相互作用。呼吸校正使Delta值降低约8.1 ppm，平均差异降低至3.1 ppm，但未改变处理的等级顺序。净光合作用也下降了16%，在潮湿的植物，但没有显着差异，这两个物种。此外，对S. affine和S.分析了生长在普通花园中的麦哲伦藻（Magellanicum）的有机质碳同位素组成（δ C-13）。这些值在每个物种内（0.9-1.2份/千）比两个物种之间（0.6份/千）的变化更大。因此，我们的结论是，在表面水膜的变化导致更大的差异，由于在泥炭藓叶片解剖特性的变化，CO2吸收和碳同位素歧视的阻力。
The relative effect of diffusional resistance due to water films (r(wf)) and leaf anatomy (r(p)) on rates of net photosynthesis and on-line measures of carbon isotope discrimination (Delta = Delta delta C-13) was investigated in Sphagnum. Sphagnum species differ in the exposure of photosynthetic cells at the leaf surface. In S. affine, photosynthetic cells are widely exposed at the surface, whereas in S. magellanicum, photosynthetic cells are enclosed within water-filled hyaline cells. This difference is expected to lead to variation in diffusive resistance within leaves (r(p)). Net photosynthesis and on-line Delta were measured at two water contents: greenhouse water content (wet) and blotted dry (dry). Without correcting for respiration, on-line Delta values differed significantly between wet (23.7 parts per thousand) and dry (30.9 parts per thousand) plants. However, there was no significant difference between species means and no species x water content interaction. Corrections for respiration lowered Delta values by approximately 8.1 parts per thousand and reduced the mean difference to 3.1 parts per thousand, but did not alter the rank order of treatments. Net photosynthesis also decreased by 16% in wet plants, but there was no significant difference between the two species. In addition, five populations of S. affine and S. magellanicum grown in a common garden were analysed for their organic matter carbon isotope composition (delta C-13). These values varied more within each species (0.9-1.2 parts per thousand) than between the two species (0.6 parts per thousand). Therefore, we conclude that variation in surface water films leads to a greater difference in resistance to CO2 uptake and carbon isotope discrimination than that due to variation in leaf anatomical properties in Sphagnum.