中文摘要：

【目的】酸性磷酸酶活性与土壤及植株体内有机磷的分解和再利用有着密切的关系。本研究以不同耐低磷玉米自交系为材料,研究低磷胁迫下玉米叶片、根组织内以及根系分泌酸性磷酸酶活性的变化及基因型差异,探讨酸性磷酸酶与玉米耐低磷之间的关系,以期更深入地了解玉米耐低磷的生理机制。【方法】以5个典型耐低磷自交系99180T、99239T、99186T、99327T、99184T和2个磷敏感自交系99152S、99270S为试验材料,采用营养液培养方法,设正常磷和低磷两种处理,分别于缺磷处理3、8和12 d时调查取样,测定地上部干重、根干重、叶片中无机磷（Pi）含量、根和地上部磷累积量、根系分泌APase活性以及叶片中APase活性,并于缺磷处理12 d测定根系内APase活性。【结果】1）缺磷使玉米地上部干重下降,根干重、根冠比增加,随着缺磷处理（3 d→8 d→12 d）时间的延长,根干重、根冠比增加幅度增大,且耐低磷自交系根干重增加幅度普遍大于敏感自交系。2）低磷条件下,玉米自交系磷吸收、利用效率存在基因型差异,耐低磷自交系99239T、99180T和99327T磷吸收效率较高,99186T和99184T磷利用效率高,敏感自交系99152S、99270S磷吸收和利用效率均较低。3）低磷处理使玉米自交系叶片无机磷（Pi）含量显著下降,耐低磷自交系99184T、99327T和99239T下降幅度较小,相对叶片无机磷含量较高。4）缺磷诱导玉米根系分泌的APase活性升高。耐低磷自交系99184T和99186T根系分泌APase活性升高幅度较大,其余3个耐低磷自交系未表现出明显优势。缺磷处理3 d、8 d,玉米根系分泌APase活性与磷累积量显著正相关,而12 d时相关性不显著;根系分泌APase活性与磷利用效率在缺磷处理12d时达显著正相关。说明玉米根系分泌APase活性与磷吸收、利用效率相关关系不稳定。5）缺磷处理12 d,各玉米自交系根组织内APase活性与根?

英文摘要：

【Objectives】Acid phosphatases affects P acquisition and use efficiency of crops. In this study,seven maize inbred lines（ five low- P tolerant and two low- P sensitive maize genotypes） were used to study their differences in acid phosphatase（ APase） activities in maize leaves,root tissue and root exudation under low P stress,and to discuss relationship between the APase activities and P efficiency. These results may explain thephysiological mechanism of low phosphorus tolerance in maize.【Methods】A hydroponic experiment were designed in two P levels and used five low- P tolerant（ 99180 T,99239T,99186 T,99327T and 99184T） and two low- P sensitive（ 99152 S and 99270S） maize genotypes as materials. We determined the shoot dry weight,root dry weight,P accumulation in root and shoot,inorganic P content in leaves,APase in leaves and root exudation under the phosphorus deficiency treatments after 3 d,8 d and 12 d,and APase in root was analyzed under the phosphorus deficiency treatments after 12 d. 【Results】1） The shoot dry weight was decreased,the root dry weight and root-shoot ratio of maize are significantly increased in the low- P tolerant maize genotypes with elongated treated time from 3 d to 8 d and 12 d in the low- P stress treatment. 2） There are significant differences in P uptakes and utilization efficiencies among different maize genotypes. Three low- P tolerant inbreds of 99239 T,99180T and99327 T have high uptake efficiency and 99186 T and 99184 T have high P- utilization efficiency,while both the P- sensitive inbreds 99152 S and 99270 S have low P- uptake and utilization efficiency. 3） The inorganic phosphorus（ Pi） contents in leaves of maize are decreased significantly under the low- P stress,but the decreases in the low- P tolerant inbreds 99184 T,99327T and 99239 T are less than in 99186 T and 99184 T under the low P,and the relative Pi contents in the leaves of the former three ones are higher than the latter two. 4） The APase activities in root exudation are incre