低磷胁迫对不同品种高粱苗期形态及生理指标的影响

以14个高粱品种为材料，设置5个磷处理水平，对高粱苗期的形态和生理指标进行了研究。结果表明， 1）不同水平磷处理对高粱苗期各形态指标均有极显著影响，其中以0.25 mmol/L作为低磷处理较适合; 2)低磷胁迫对高粱幼苗各形态指标均有不利影响，干重、植株地上部含磷量受低磷的影响较大，可作为耐低磷高粱品种的筛选指标; 3)不同高粱品种对低磷的耐性存在明显的基因型差异， 聚类分析显示八月齐属相对耐低磷性强的品种，农858属低磷敏感型品种; 4)低磷下叶绿素和可溶性蛋白含量下降，丙二醛（MDA）含量及超氧化物歧化酶（SOD）、过氧化物酶（POD）活性升高，除可溶性蛋白外，叶绿素、 MDA、 SOD和POD活性均表现为耐低磷性强的相对变化率较小，耐低磷性弱的相对变化率较大。

Effects of low phosphorous stress on the morphologies and physiological indices of different sorghum cultivars at seedling stage

The effects of low P stress on the morphologies and physiological indices of sorghum were investigated with 14 sorghum cultivars at seedling stage. The results show, 1) Different P supply levels significantly affect the morphologies of sorghum seedlings (P0.01). P supply level of 0.25 mmol/L was found to be the proper P level for screening P-tolerance cultivars; 2) Low P stress decreases the P content of shoot, and negatively influences morphological development of sorghum seedlings, especially on plant dry weight accumulation. Therefore shoot P content and above ground dry weight were recommonded as screening indices for low P-tolerance cultivars at sorghum seedling stage; 3) Different cultivars responded differently to low P stress. Bayueqi was a low P tolerance cultivar, while Nong858 was a low-P sensitive cultivar through cluster analysis; 4) P deficiency leads to low chlorophyll and soluble protein contents, high MDA content and high SOD and POD activities in sorgum seedlings. Except soluble protein, relative variations in the tested indices were small in low-P tolerance cultivars, high in low-P sensitive cultivars.