作 者：
徐子先;李银水;韩配配;廖祥生;胡小加;谢立华;余常兵;张秀荣;廖星;秦璐
单 位：
中国农业科学院油料作物研究所/农业部油料作物生物学与遗传育种重点开放实验室
关键词：
芝麻;铵硝配比;光合特性;光合色素;叶绿素荧光
摘 要：
为了明确不同氮素形态(铵硝配比)对芝麻苗期光合荧光特性的影响,探究适合芝麻生长的铵硝配比,采用营养液栽培方法研究了不同铵硝配比(10∶0、9∶1、3∶1、1∶1、1∶3、1∶9、0∶10)对芝麻品种中芝13(ZZ13)和漯12(L12)苗期光合特性、光合色素、叶绿素荧光参数的影响。结果表明,铵态氮比例过高显著抑制芝麻生长,铵硝配比为10∶0和9∶1时植株死亡,高比例铵态氮(铵硝配比3∶1)处理的芝麻幼苗地上部干质量显著低于其他处理;随着铵态氮比例降低,抑制作用减弱,并且适当配施硝态氮(铵硝配比1∶9)时2个芝麻品种地上部干质量达最大值,ZZ13和L12的叶绿素a、b含量及叶绿素总量分别在铵硝配比1∶9和0∶10时达到最高,而铵硝配比3∶1时上述光合色素含量大幅降低。铵硝配比1∶9时,ZZ13和L12的净光合速率(Pn)和蒸腾速率(Tr)均最大,而高比例铵态氮处理时Pn和Tr均显著降低,两者对铵态氮的响应较为明显。此外,与纯硝态氮处理相比,铵硝配比1∶9显著提高了ZZ13的光系统活性,表现为光系统Ⅱ最大量子效率(Fv/Fm)和实际光化学效率(ΦPSⅡ)显著增加,非光化学猝灭系数(q N)显著降低,但对L12光系统Ⅱ活性的提高不明显;而铵硝配比3∶1显著抑制了ZZ13和L12的光系统Ⅱ活性,表现为Fv/Fm、ΦPSⅡ和q P(光化学猝灭系数)值显著降低,Fo(基础荧光)和q N值显著增加。可见,铵硝配比1∶9最适合芝麻生长,尤其是对于ZZ13,其促进光合作用的主导因素是显著提高了光系统Ⅱ活性,而对芝麻叶片光合色素含量及组成比例的影响不显著;高比例铵态氮对芝麻叶片光合色素含量及组成比例、光系统Ⅱ活性、Pn和Tr都产生了不良影响,进而严重抑制芝麻的光合作用和生长。
译 名：
Effect of Different NH_4~+-N/NO_3~--N Ratios on the Photosynthetic and Fluorescence Characteristics of Sesame Seedlings
作 者：
XU Zixian;LI Yinshui;HAN Peipei;LIAO Xiangsheng;HU Xiaojia;XIE Lihua;YU Changbing;ZHANG Xiurong;LIAO Xing;QIN Lu;Oil Crops Research Institute of Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetics Improvement of Oil Crops of the Ministry of Agriculture;
关键词：
sesame;;NH_4~+-N/NO_3~--N ratio;;photosynthetic characteristics;;photosynthetic pigments;;chlorophyll fluorescence
摘 要：
In order to explore the effect of different NH_4~+-N/NO_3~--N ratios on the photosynthetic characteristics of sesame seedlings and the suitable ratio for the growth of sesame,hydroponic experiments were performed to study the different NH_4~+-N/NO_3~--N ratios( 10∶ 0,9∶ 1,3∶ 1,1∶ 1,1∶ 3,1∶ 9,0∶ 10) on the photosynthetic characteristics,pigments and chlorophyll fluorescence of sesame cultivars ZZ13 and L12. Results showed that high NH_4~+-N/NO_3~--N ratio significantly inhibited the growth of sesame,resulting in the death( 10∶ 0 and 9∶ 1) and the reduced dry weight( 3∶ 1) of sesame seedlings. With the decrease of NH_4~+-N,the inhibition were alleviated,moreover,the shoot dry weight of ZZ13 and L12 reached maximum under NH_4~+-N/NO_3~--N ratio at 1∶ 9. While the the content of Chl a,Chl b,Chl( a + b) achieved the highest values under NH_4~+-N/NO_3~--N ratio at 1 ∶ 9 and 0 ∶ 10,respectively. However,these parameters greatly decreased when applied the NH_4~+-N/NO_3~--N ratio at 3∶ 1. The photosynthetic rate( Pn) and respiratory rates( Tr) of two cultivars were also greatest under NH_4~+-N/NO_3~--N ratio at 1 ∶ 9,reversely,the Pn and Tr of two cultivars were both greatly reduced when applied more NH+4-N( 3∶ 1 and 1∶ 1),these two parameters were sensitive to addition of NH_4~+-N. Furthermore,compared to the total NO-3-N treatment,appropriately applied with NH_4~+-N 1∶ 9 significantly improved the PSⅡactivity of ZZ13,as indicated by the significant increase of Fv/Fm,ΦPSⅡand decrease of q N. However,the NH_4~+-N/NO_3~--N ratio at 3∶ 1 both suppressed the PSⅡactivity of two cultivars,these parameters exhibited reversed tendency as compared with ratio at 1∶ 9. These results indicated that the NH_4~+-N/NO_3~--N ratio at 1∶ 9 was more suitable for the growth of sesame seedlings in the present study,especially for ZZ13,the improvement of the PSⅡactivity might promote the photosyntheis of sesame. While the higher proportion of NH_4~+-N had an undesirable influence on the photosynthetic pigment content and its composition,PSⅡactivity,Pn and Tr,then finally seriously inhibited the photosynthesis and growth of sesame seedlings.
