%0 Journal Article
%A JIN Ze-Xin*
%A MA Jin-E
%A ZHANG Wen-Biao
%T The Diurnal Changes of Photosynthesis in the Endangered Plant　<em>Sinocalycanthus chinensis</em> and Its Accompanying Plants
%D 2007
%R 10.7525/j.issn.1673-5102.2007.06.012
%J Bulletin of Botanical Research
%P 708-714
%V 27
%N 6
%X The photosynthetic parameters of <em>Sinocalycanthus chinensis</em> in both overstory and understory, including the diurnal changes of net photosynthetic rate (<em>Pn</em>), intercellular CO<sub>2</sub> concentration (<em>Ci</em>), dark respiration rate (<em>Rd</em>) and stomatal resistance (<em>rs</em>), were measured using a LCA4 Portable Photosynthesis System. The photosynthetic parameters of the accompanying plants such as <em>Boehmeria platanifolia</em>, <em>Rhus chinensis</em> and <em>Weigela japonica</em> var. <em>sinica</em> were also measured for comparison. The results showed that the diurnal changes of photosynthesis of <em>S. chinensis</em> in the overstory took on &ldquo;double-peak&rdquo; curve with remarkable midday depression. The midday depression was mainly due to non-stomatal limitations. On the contrary, the diurnal changes of photosynthesis of <em>S. chinensis</em> in the understory took on &ldquo;one-peak&rdquo; curve with low <em>Pn</em>. The maximal <em>Pn</em> was only half of that of <em>S. chinensis</em> in the overstory. The correlation analysis showed that the limiting factor for this low <em>Pn</em> might be light intensity (<em>p</em>=0.001). Compared with its accompanying plants, <em>S. chinensis</em> was in a disadvantaged status in the community with low photosynthetic capacity, water use efficiency, and the ratio of photosynthetic rate to respiration rate.
%U https://bbr.nefu.edu.cn/EN/10.7525/j.issn.1673-5102.2007.06.012