Plant Photobiology Laboratory, USDA-Agricultural Research Service, Beltsville Agricultural Research Center, 20705, Beltsville, MD, USA.
Photosynth Res. 1990 Jan;23(1):67-72. doi: 10.1007/BF00030064.
This study investigated the basis of the negative relationship between leaf size and photosynthetic rate per unit of area among five cultivars of soybeans. Exposure of developing mainstem leaves to light, and sizes and light saturated photosynthesis rates of those leaves at maturity were compared in cultivars grown in field plots for two years at Beltsville, Maryland, USA. Plants were grown both in stands at 2.5 cm by 1 m spacing and as isolated plants. While cultivar differences in leaf size were large and consistent in both planting arrangements, significant cultivar differences in light saturated photosynthetic rates were found only in plants grown in stands. Similarly, leaf size was significantly correlated with specific leaf weight only for plants grown in stands. The mainstem apex and developing mainstem leaves experienced more severe shading in large-leaved cultivars than in small-leaved cultivars when plants were grown in stands. Thus, cultivar differences in photosynthetic capacity were probably a consequence of differences in the exposure of developing leaves to light.
本研究旨在探究五个大豆品种中单位面积叶片大小与光合速率呈负相关的基础。在马里兰州贝尔茨维尔的田间试验中，比较了两年生大豆主茎叶片在发育过程中对光照的暴露程度、成熟叶片的大小和光饱和光合速率。植株以 2.5 厘米×1 米的间距种植于垄上和单独种植。尽管在两种种植方式下，叶片大小的品种差异都很大且一致，但只有在垄上种植的植株中才发现光饱和光合速率的显著品种差异。同样，只有在垄上种植的植株中，叶片大小与比叶重显著相关。当植株垄上种植时，与小叶片品种相比，大叶片品种主茎顶端和发育中的主茎叶片受到更严重的遮荫。因此，品种间光合能力的差异可能是发育中叶片对光照暴露的差异所致。
