低磷胁迫对不同基因型甜菜抗性生理特征的效应

选用对低磷胁迫抗性各异的3个甜菜品种:品20、品17和品14,在人工培养室内采用沙培试验法,研究了甜菜抗耐低磷胁迫的生理机制。结果表明,低磷胁迫限制了甜菜对磷的吸收,导致植株含磷量和生物产量显著下降;不同品种间差异显著,品14降幅最大,品17次之,品20最小。与足磷处理(P 100μmol/L)相比,低磷胁迫后甜菜品种间体内抗性生理特征差异显著。其中,品14和品17的丙二醛含量、脯氨酸含量、过氧化物酶活性均显著增加;品20的丙二醛含量、脯氨酸含量极显著下降,而过氧化物酶活性变化不显著。叶片中Mg2+-ATPase活性降低,不同品种降幅各异,从小到大依次为品20品17品14,其中品20与后两者间的差异均达显著。品20和品17体内的钙调素(CaM)含量显著增加,而品14变化不明显,其相对值从大到小依次为品20品17品14,差异显著,与品种自身抗磷胁迫能力顺序一致。不同磷素营养条件对甜菜抵御外界不良环境有较大影响,叶片在受到热伤害时,抗磷胁迫能力较弱的品14和品17在低磷胁迫时质膜损伤率显著增加;而抗磷胁迫能力较强的品20叶片质膜的损伤率显著下降,抗热能力得到改善。

Effects of Pi deficiency on characteristics of resistant physiology in different sugar beet(Beta vulgaris L.)genotypes

The effects of phosphorus stress on the physiological properties of the individual attached leaves of sugar beet plants (Beta vulgaris L., cv.14, cv.17 and cv.20 with different resistance to phosphorus stress) was studied using the sand culture in growth chambers. The results were showed as follows: P deficiency constrained P uptake, consequently, the P contents in plant and biomass in all three varieties were decreased significantly among which, P content and biomass of cv.14 decreased most, followed by cv.17 and cv.20. Pi deficiency resulted in different physiological responses which was genetic dependent: First, the contents of MDA, Pro and POD activity were increased significantly in cv.14 and cv.17, while the content of MDA and Pro decreased significantly in cv.20. The activity of POD changed slightly; Second, the activity of Mg²⁺-ATPase in all three varieties were decreased with the order of cv.20<cv.17<cv.14; Third, compared with the normal Pi supply（P 100 μmol/L）, the contents of CaM content in sugar beet leaf was significantly increased in cv.20 andcv.17 under Pi deficiency, but it kept stable in cv.14. Fourth, different Pi nutrient levels had a big influence on the resistant ability of sugar beet to harsh environment which was also genetic dependent, Plasma membrane permeability of individual attached leaves in cv.14 and cv.17 increased significantly under higher temperature (40℃), while it decreased significantly in cv.20 indicating resistant ability to heat stress was improved.