不同负载量对苹果^(13)C和^(15)N分配、利用的影响

Effects of different fruit load on distribution and utilization characteristics of ^(13)C and ^(15)N of apple

【目的】利用稳定性同位素13C和15N示踪技术,研究了不同负载量对苹果13C和15N分配、利用的影响,从营养吸收的角度阐明负载量对苹果生长发育影响的机理,为疏果及提高氮肥利用率提供依据。【方法】以5年生垄栽王林/SH38/八棱海棠苹果为试材,于3月27日挖环状沟施肥,每株施入15N-尿素10 g,同时施N 110.33 g、P2O5143.15 g、K2O 151.26 g。在坐果后,立即进行疏果处理,试验设3个处理为对照(不疏果)、2/3负载量(疏掉其中1/3的果实)和1/3负载量(疏掉其中2/3的果实);于果实成熟期(9月6日)对已处理的植株进行整株13C标记处理。标记72 h后破坏性采样,测定13C和15N丰度。13C丰度用DELTA V Advantage同位素比率质谱仪测定,15N丰度用ZHT-03质谱计测定。【结果】与对照(不疏果)相比,2/3负载量和1/3负载量处理,果实平均单果重分别增加了17.68%和48.57%,根冠比分别增加了7.69%和15.38%,而其平均单株产量却显著降低,分别为对照的50.18%和78.60%;3处理单位干截面积平均产量分别为0.83 kg/cm2、0.54 kg/cm2和0.33 kg/cm2,三者之间差异显著;负载量增加促进叶片制造的13C同化物向果实中转移,减少了向根系的运输,对照、2/3负载量和1/3负载量处理的果实13C分配率分别为39.81%、29.25%和16.46%,根系13C分配率则分别为16.79%、19.98%和24.64%;负载量增加显著降低了植株15N的利用率,对照、2/3负载量和1/3负载量3个处理的植株15N利用率分别为8.51%、10.11%和13.23%。3个处理各器官的氮原子百分超(Ndff)值均表现为果实>当年生枝>根系>叶片>多年生枝>中心干,不同处理间Ndff值的差异主要表现在果实和根系,果实的Ndff值随着负载量的增加而增大,对照的Ndff值达到2.76%,分别为2/3负载量和1/3负载量处理的1.17倍和1.31倍,而根系则表现出相反的趋势;15N分配率与13C分配率表现出相同的趋势,15N分配率较高的器官,13C分配率也处于较高水平。【结论】负载量增加可促进叶片制造的13C同化物向果实中转移,减少向根系的运输,对15N的吸收利用降低。当单位干截面积产量为0.54 kg/cm2时,能有效协调树体的碳、氮营养分配,对王林苹果的生产效果最佳。

【Objectives】Stable isotope13 C and15N tracer technology was used to study effects of different fruit load on characteristics of distribution and utilization of13 C and15N of apple. Based on the nutrient absorption,theory of the effects of fruit load on growth and development of apple was illustrated to provide evidence for fruit thinning and increasing N fertilizer utilization. 【Methods 】The materials were 5- year-old apple tree( Wanglin / SH38/ Malus robusta Rehd.),and the fertilizer was applied on March 27,2013. The method was annular groove fertilization:15N-urea 10 g,N 110. 33 g,P2O5143. 15 g and K2 O 151. 26 g each plant. After the fruiting,the fruits were thinned: control,2 /3 fruit load and 1 /3 fruit load. The trees were labeled with13 C at the fruit maturity( September6). 72 hours after labeled,the trees were sampled to determine13 C and15N abundance.13 C abundance was determined by DELTA V Advantage isotope ratio mass spectrometer,15 N abundance was determined by ZHT- 03 mass spectrograph. 【Results】Compared with the control,the average single fruit weights of the 2 /3 fruit load and1 /3 fruit load are increased by 17. 68% and 48. 57% respectively,root-shoot ratios are increased by 7. 69% and15. 38% respectively,however,the average yields per plant are significantly decreased to 50. 18% and 78. 60% of control,respectively. The unit area average dry yields of the three treatments are significantly different,0. 83 kg / cm2,0. 54 kg /cm2 and 0. 33 kg / cm2,respectively. When the fruit load increases,more13C- assimilate transports to fruit and results in the decrease of the13C- assimilation in roots. The13 C partitioning rates in fruits of the three treatments( control,2 /3 fruit load and 1 /3 fruit load) are 39. 81%,29. 25% and 16. 46%,and the rates of roots are 16. 79%,19. 98% and 24. 64%. The15 N use efficiencies of the three treatments are 8. 51%,10. 11%and 13. 23%. The Ndff values of the three treatments are consistent,and in order: fruit > biennial > root > leaves >branch of perennial > trunk. With fruit load increasing,the Ndff values of the fruits are increased,and the values of the control is 2. 76%,which is 1. 17 and 1. 31 times of that of the 2 /3 fruit load and 1 /3 fruit load,respectively. The15 N partitioning rate is consistent with that of13 C,and when the15 N partitioning rates are high,the13 C partitioning rates are also high in organ. 【Conclusions】With fruit load increasing,more13C- assimilate is transported to fruits and results in the decrease of the13C- assimilate in roots,and the15 N utilization is decreased.It is good for apple production that the unit area average dry yield is 0. 54 kg / cm2.