%0 Journal Article
%T Leaf photosynthetic potential in canopy layers of un-thinned and thinned apple orchards<br>苹果密植园与间伐园树冠层内叶片光合潜力比较
%A ZHANG Ji-xiang
%A WEI Qin-ping
%A ZHANG Jing
%A WANG Lian-xin
%A WANG Cui-ling
%A SUN Xie-ping
%A SONG Kai
%A <br>张继祥
%A 魏钦平
%A 张静
%A 王连新
%A 王翠玲
%A 孙协平
%A 宋凯
%J 应用生态学报
%D 2009
%I 
%X Through the comparison of leaf photosynthetic potential and of photosynthetically active radiation (PAR), leaf nitrogen concentration (Nl), and mass per unit leaf area (Ml) in different canopy layers of un-thinned orchard (UOD) and thinned orchard (TOD), this paper studied the effects of UOD rebuilding on the use efficiencies of PAR and nitrogen, and their relationships to the fruit yield and quality. Thinning obviously improved the radiation environment in canopy. The radiation distribution in TOD canopy was more uniformly than that in UOD canopy, and the invalid space with relative PAR (PARr) less than 30% in TOD approached to zero, while the minimum mean PARr in UOD was 17%, and the space under 0.3 of relative canopy height was invalid. The leaf photosynthetic efficiency in TOD was notably improved. Comparing with that in UOD, the photsynthetic rate (Pn) at the middle and bottom of the canopy in TOD was increased by 7.8% and 10.2%, respectively. Meanwhile, the photosynthetic potential parameters such as maximum carboxylation rate (Vmax) and maximum electron transfer rate (Jmax) also increased remarkably in TOD. The leaf photosynthetic potential had significant correlation with Nl, and the Nl was strongly correlated with PARr. As a result, leaf photosynthetic potential and PARr could be estimated according to the spatial distribution of relative leaf nitrogen concentration (Nlr).
%K un-thinned orchard (UOD)
%K thinned orchard (TOD)
%K photosynthetically active radiation (PAR)
%K photosynthetic potential<br>密植园
%K 间伐园
%K 辐射通量密度
%K 光合潜力
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=90BA3D13E7F3BC869AC96FB3DA594E3FE34FBF7B8BC0E591&jid=42FEDDFE54F8BCD9D5FD1926ABDD7722&aid=4D2D887B58CC0F4262516609C0D5CD9C&yid=DE12191FBD62783C&vid=A04140E723CB732E&iid=59906B3B2830C2C5&sid=2E010CE1EA4F1424&eid=D1CAD49A2C52936F&journal_id=1001-9332&journal_name=应用生态学报&referenced_num=0&reference_num=0