Li Lingyu, Yang Haomeng, Peng Lianwei, Ren Weibo, Gong Jirui, Liu Peng, Wu Xinhong, Huang Fang
Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Front Plant Sci. 2019 Feb 19;10:170. doi: 10.3389/fpls.2019.00170. eCollection 2019.
Sheepgrass [ (Trin.) Tzvel] is a valuable forage plant highly significant to the grassland productivity of Euro-Asia steppes. Growth of above-ground tissues of is the major component contributing to the grass yield. Although it is generally known that this species is sensitive to ecosystem disturbance and adverse environments, detailed information of how coping with various nutrient deficiency especially phosphate deprivation (-Pi) is still limited. Here, we investigated impact of Pi-deprivation on shoot growth and biomass accumulation as well as photosynthetic properties of . Growth inhibition of Pi-deprived seedlings was most obvious and reduction of biomass accumulation and net photosynthetic rate (Pn) was 55.3 and 63.3%, respectively, compared to the control plants grown under Pi-repleted condition. Also, we compared these characters with seedlings subjected to low-Pi stress condition. Pi-deprivation caused 18.5 and 12.3% more reduction of biomass and Pn relative to low-Pi-stressed seedlings, respectively. Further analysis of chlorophyll fluorescence and thylakoid membrane protein complexes using 2D-BN/SDS-PAGE combined with immunoblot detection demonstrated that among the measured photosynthetic parameters, decrease of ATP synthase activity was most pronounced in Pi-deprived plants. Together with less extent of lipid peroxidation of the thylakoid membranes and increased ROS scavenger enzyme activities in the leaves of Pi-deprived seedlings, we suggest that the decreased activity of ATP synthase in their thylakoids is the major cause of the greater reduction of photosynthetic efficiency than that of low-Pi stressed plants, leading to the least shoot growth and biomass production in .
羊草[（Trin.）Tzvel]是一种珍贵的饲用植物，对欧亚草原的草地生产力具有重要意义。羊草地上组织的生长是构成草产量的主要部分。尽管人们普遍知道该物种对生态系统干扰和不利环境敏感，但关于其如何应对各种养分缺乏，尤其是缺磷（-Pi）的详细信息仍然有限。在此，我们研究了缺磷对羊草的地上部生长、生物量积累以及光合特性的影响。与在磷充足条件下生长的对照植株相比，缺磷幼苗的生长抑制最为明显，生物量积累和净光合速率（Pn）分别降低了55.3%和63.3%。此外，我们将这些性状与遭受低磷胁迫条件的幼苗进行了比较。相对于低磷胁迫幼苗，缺磷分别使生物量和Pn降低了18.5%和12.3%。使用二维蓝绿温和胶/十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（2D-BN/SDS-PAGE）结合免疫印迹检测对羊草叶绿素荧光和类囊体膜蛋白复合物进行进一步分析表明，在所测定的光合参数中，缺磷植株中ATP合酶活性的降低最为显著。结合缺磷幼苗叶片中类囊体膜脂质过氧化程度较低以及活性氧清除酶活性增加的情况，我们认为其类囊体中ATP合酶活性降低是光合效率下降幅度大于低磷胁迫植株的主要原因，导致羊草的地上部生长和生物量生产最少。
