【摘要】 为探讨落叶松幼苗光合特性对氮、磷营养缺乏的响应规律,在温室内用砂培方法培养和处理落叶树幼苗,测定了净光合速率和叶绿素荧光等反映其光合能力的参数,分析了落叶松幼苗的光合特性对氮、磷营养缺乏的响应规律.结果表明,氮素供应不足(1mmol·L-1)时,落叶松幼苗针叶的全氮含量、叶绿素含量和净光合速率与对照相比都显著降低,分别下降了37%、31%和5 9% ,同时,Fv/Fm(反映光系统II最大光能转换效率)和Fv/Fo(反映光系统II潜在活性)也分别下降了2 2 %和5 7% ,而叶片可溶性蛋白含量只有微弱下降.磷素供应不足(1/ 8mmol·L-1)时,叶片全氮和全磷含量、叶绿素含量、叶片可溶性蛋白含量和Fv/Fm 与对照相比差异均不显著,净光合速率和Fv/Fo 下降13% .氮、磷同时缺乏时,上述各项指标的变化与单独缺氮处理的相似,这意味着本实验中缺磷处理(1/ 8mmol·L-1)对落叶松幼苗光合特性影响相对较小.更多还原

【Abstract】 In this paper,the responses of larch seedling’s photosynthetic characteristics to N and P deficiency were studied in greenhouse from April to September,2002.On April 10,one-year-old larch seedlings,after their roots washed and sterilized,were transplanted into a plastic pot （diameter 30 cm,height 27 cm） containing sterilized and washed quartz sand,and supplied with complete nutrient solution （4 mmol NH₄NO₃·L -1,1 mmol KH₂PO₄·L -1,1 mmol KCl·L -1,1 mmol CaCl₂·L -1,0.6 mmol MgSO₄·L -1,0.02 mmol FeCl₃·L -1,6 μmol MnCl₂·L -1,0.016 mmol H₃BO₃·L -1,0.3 μmol ZnCl₂·L -1,0.3 μmol CuCl₂·L -1,and 0.3 μmol NaMoO₄·L -1）.On May 20,the seedlings were treated with four different combinations of N and P supply,i.e.,control （CK,8 mmol N·L -1 and 1 mmol P·L -1）,low nitrogen supply （LN,1 mmol N·L -1 and 1 mmol P·L -1）,low phosphorus supply （LP,8 mmol N·L -1 and 1/8 mmol P·L -1）,and low nitrogen with low phosphorus supply （LN-LP,1 mmol N·L -1 and 1/8 mmol P·L -1）.In treatment LN,the other nutrients were given as CK,while in treatment LP,the K level was adjusted by KCl,with the other nutrients kept as CK.On September 4,the net photosynthetic rate,chlorophyll fluorescence parameters,chlorophyll content,total soluble protein content,and N and P contents of the needle were determined.The results showed that in treatment LN,the N content,chlorophyll content,net photosynthetic rate （P_n）,maximal PSII efficiency （F_v/F_m） and potential PSII activity （F_v/F_o） of the needle declined significantly by 37%,31%,58%,22% and 57%,respectively,while in treatment LP,the N and P contents,chlorophyll content,total soluble protein content and F_v/F_m had no significant differences with CK,but the P_n and F_v/F_o was 13% lower than CK.The variation tendency and extent of P_n,chlorophyll fluorescence parameters,and other physiological indices in treatment LN-LP were similar to those in treatment LN.更多还原