分根交替灌溉对桃树^(13)C分配和光合能力的影响

Effects of Partial Root-zone Alternative Irrigation on Distribution of13C-assimilate and Photosynthesis Capability of Peach Trees

为探究分根交替灌溉对肥城桃^(13)C同化物分配的影响,以2年生肥城桃为试材,分根区处理设置1/4、2/4、3/4、4/4 4种灌水根区和500、1 000 m L 2种灌水量,交替周期处理设置2/4、4/4 2种灌水根区和4、8、16d 3种交替间隔,研究不同处理对各器官^(13)C分配率、光合指标和荧光参数的影响。结果表明,全根区(C)处理叶部和新梢的^(13)C分配率显著高于分根区(P)处理,分根区(P)处理果肉和根部的^(13)C分配率则显著高于全根区(C)处理,多年生枝和主干的规律不明显;2/4根区8d交替处理果肉和根部的^(13)C分配率最高,而新梢的^(13)C分配率显著低于其它处理;净光合速率和蒸腾速率随灌水根区和灌水量的减少降低,蒸腾速率较净光合速率降低的幅度更大,单叶水分利用效率随之提高,其中2/4根区8d交替处理的净光合速率和单叶水分利用效率显著高于其它处理;荧光参数受处理的影响较小。综上所述,2/4根区8d交替处理的净光合速率和单叶水分利用效率均较高,能促进光合产物向果实的分配并抑制新梢的旺长。本研究结果为分根交替灌溉在果树生产中的应用提供了理论依据。

Two-year old Feicheng peach trees（Prunus persica L.）grown in split-root pots were used to study the effects of partial root-zone alternative irrigation （PRAI） on the translocation and distribution of ^13C-assimilate. The root-zone treatments included 1/4, 2/4, 3/4 and 4/4 root-zone, the irrigation volume treatments included 500 and 1 000mL, the alternative cycle treatments included 4, 8 and 16ays, to study the effects of different treatments on the distribution of ^13C-Assimilate, photosynthesis and chlorophyll fluorescence parameters. The results indicated that distribution rate of ^13C in leaves and new shoots of the C treatment were significantly higher than the P treatment, however the distribution rate of ^13C in roots and sarcocarp of P treatment were significantly higher than the C treatment. The changes of distribution rate of ^13C in branches and trunks were relatively complex. Then the P8 treatment displayed the highest distribution rates of ^13C in roots and sarcocarp, and the distribution rates of ^13C in new shoots were significantly lower than the other treatments. The results of the photosynthesis capability indicated that net photosynthetic rate （Pn） and transpiration rate （Tr） of peach leaves decreased with the root-zone and irrigation volume decreasing, and the decreasing extent of the transpiration rate was significantly larger than that of net photosynthetic rate, therefore, water use efficiency increased. The net photosynthetic rate and water use efficiency of P8 treatment were significantly higher than the other treatments. Moreover, fit was the irrigation volume rather than the root-zone or alternative cycles that affected the net photosynthetic rate, transpiration rate and water use efficiency of leaves. The chlorophyll fluorescence parameters including Fv/Fm, F＇v/F＇m, ΦPSIand qPwere all less affected by the irrigation treatments. In conclusion, the P8 treatment had higher net photosynthetic rate and water use efficiency, and could promote the tree distribute more ^13C-assimilate to sarcocarp and inhibit ^13C-assimilate distribute to new shoots. This study provided theoretical basis for PRAI on fruit production application.