中文摘要：

采用盆栽砂培,在室内人工可控和室外自然环境条件下,利用前期研究已经获得的对低磷胁迫抗性弱（品14）、中（品17）和强（品20）的3类种质材料各1个,进行了长期低磷胁迫（P 1μmol/kg）条件下不同基因型甜菜光合特性的研究。结果表明：1）低磷胁迫显著（P〈0.05）降低了甜菜叶片无机磷和叶绿素含量,品20的降幅显著低于品14;2）低磷胁迫对3个品种的气孔导度、蒸腾速率均有显著或极显著（P〈0.01）的负效应,对胞间CO2浓度的效应因品种而异,与P 100μmol/kg处理相比,品14显著下降,品17无变化,品20显著增加;3）与P 100μmol/kg处理相比,低磷胁迫使3个品种单叶光合速率降幅均达到了极显著水平,但不同品种之间表现各异,品14降幅最大,品20最小,品17居中,且3个品种间的差异均达到了显著或极显著;4）不同生长条件使甜菜对低磷胁迫在单叶光合速率方面产生不同的抵抗能力,在室内培养条件下,同样的磷胁迫水平对各品种甜菜光合作用的阻碍均显著小于自然环境;5）低磷胁迫条件下,甜菜各品种在植株磷含量、气孔导度、蒸腾速率、胞间CO2浓度和单叶光合速率等性状上的抗胁迫指数大小与品种自身的抗低磷胁迫强弱的顺序完全一致,即品20〉品17〉品14。

英文摘要：

Three different sugar beet genotypes [ Beta vulgaris L. cv. 14 （diplont）, cv. 17 （tetraplont）, cv. 20 （triplont） ] screened in a former research with different resistant abilities to P deficiency were used to investigate the effects of long term phosphorus stress（P 1μmol/kg） on photosynthetic properties of the individual attached leaves by the methods of sand culture in growth chambers and outdoor natural condition respectively. The results show that contents of Pi and chlorophyll are decreased significantly （p 〈 0.05） under the long term phosphorus stress, the decreased rates of the two properties of the genotype cv.20 are obviously （ P 〈 0.05）smaller than those of cv. 14. P deficiency has a significant negative effect on stomatal conductance and transpiration rate. Effects of P stress on intercellular CO2 concentration vary with the cultivars, significant decrease for cv. 14, little change for cv. 17, and significant increase for cv.20. To compare with the treatment of P 100 μmol/kg, photosynthetic rates of the three cultivars under the P stress are significantly decreased, the decreases are cultivar dependent, of them cv. 14 is the largest, cv. 17 is in the middle, cv.20 is the smallest, and the difference of photosynthetic rates between the cuhivars are also significant. Effects of the P stress on photosynthetic rate varies with the growth environments, the resistant index under the growth chamber environment is larger than that under the outdoor condition. Under the conditions of P deficiency, the magnitude of resistant indices concerning the characteristics of P content of beet plant, stomatal conductance, transpiration rate, intercellular CO2 concentration, transpiration rate and photosynthetic rate of the individual cultivar are completely in accord with the resistant ability of the respective cultivar, i.e. cv.20 〉 cv.17 〉 cv. 14.