加利福尼亚索诺兰沙漠中多刺烟树（Psorothamnus spinosus）的茎光合作用。

Stem photosynthesis in Psorothamnus spinosus (smoke tree) in the Sonoran desert of California.

作者信息

Nilsen Erik T, Meinzer F C, Rundel P W

机构信息

Department of Biology, Virginia Polytechnic Institute and State University, 24061, Blacksburg, VA, USA.

Hawaiian Sugar Planters' Association, P.O. Box 1057, 96701, Aiea, Hawaii, USA.

出版信息

Oecologia. 1989 May;79(2):193-197. doi: 10.1007/BF00388478.

DOI:10.1007/BF00388478

PMID:28312855

Abstract

Stem photosynthetic responses to environmental parameters were investigated with Psorothamnus spinosus in the Sonoran Desert of California. Light saturation of stem photosynthesis was equal to maximum midday summer irradance (1600-2000 μmol·m·s). The optimum temperature for stem photosynthesis was 39°C, and lower stem temperatures (27-35°C) caused significant decreases (up to 50%) in stem photosynthesis. Positive stem photosynthesis was maintained up to 51°C. Stem photosynthesis was relatively insensitive to increasing vpd up to 5 kPa; However, stem conductance decreased by 25% at a vpd of 5 kPa. At vpd greater than 5 kPa stem photosynthesis decreased relatively more than that of stem conductance causing a decrease in water use efficiency and an increase an intercellular carbon dioxide concentration. Maximum stem photosynthetic rates were low (6.2-10.6 μmol·m·s) on a stem surface area, but, stem photosynthetic rates of young shoots were substantially higher (19.5-33.3 μmol· m·s) on a projected area basis.

摘要

在加利福尼亚州索诺兰沙漠，对多刺补骨脂的茎光合对环境参数的响应进行了研究。茎光合作用的光饱和等于夏季中午的最大辐照度（1600 - 2000 μmol·m·s）。茎光合作用的最适温度为39°C，较低的茎温度（27 - 35°C）会导致茎光合作用显著下降（高达50%）。在高达51°C时仍保持正向的茎光合作用。茎光合作用对vpd增加至5 kPa相对不敏感；然而，在vpd为5 kPa时，茎导度下降了25%。当vpd大于5 kPa时，茎光合作用的下降相对大于茎导度的下降，导致水分利用效率降低和细胞间二氧化碳浓度增加。基于茎表面积的最大茎光合速率较低（6.2 - 10.6 μmol·m·s），但基于投影面积，幼嫩枝条的茎光合速率显著更高（19.5 - 33.3 μmol·m·s）。