谷子光合特性及产量最优的氮磷肥水平与细胞分裂素6-BA组合研究

Optimum combining rate of N and P fertilizer with 6- BA for highest photosynthetic efficiency and yield in foxtail millet

【目的】谷子的干物质90%来源于光合作用,提高谷子群体光能利用,维护中上部叶片较大的光合速率及持续时间对于产量形成十分重要。研究合理施肥对谷子光合特性的影响将为谷子生产提供合理施肥依据。【方法】以张杂谷5号为试材,采用三因素二次通用旋转组合设计进行田间试验。设5个氮水平为22、69、138、207、254kg/hm^2;5个磷(P_2O_5)水平为11、36、72、108、133 kg/hm^2;细胞分裂素6-BA[0.5%(v/v)]于开花期开始,每天16:00左右叶面喷施,连喷4 d。灌浆期调查旗叶叶绿素含量、净光合速率、叶面积系数和产量。【结果】随着施磷量的增加,叶片净光合速率、叶面积系数先迅速上升后缓慢下降;随着喷施6-BA浓度的增加,叶片净光合速率、叶面积系数先迅速上升后下降明显。叶绿素含量受氮、磷、6-BA影响显著,三个因素变化趋势比较一致,随着施氮、磷的用量和喷施6-BA的浓度升高,叶绿素含量均呈先增后降的趋势,产量也随氮、磷、6-BA的水平变化显著。根据一次项对产量的作用方程来看,增产作用磷>6-BA>氮。在供试施用水平内,氮、磷、6-BA对产量的影响均呈抛物线状,随着施磷的增加,产量先迅速增加后缓慢下降,随着施氮量、6-BA用量的增加,产量先迅速增加后下降明显。氮肥和细胞分裂素6-BA之间交互作用对叶绿素含量、净光合速率、叶面积系数和产量均有显著影响。【结论】在供试条件下,适宜氮磷施用水平配合喷施6-BA可显著增加谷子的叶面积系数、叶绿素含量和净光合速率,超过适宜用量后,降低作用也很明显。氮、磷、6-BA与产量间回归关系极显著,拟合程度较高,可用于实际产量预测。对于张杂谷5号,最高产量为N175.0 kg/hm^2,P_2O_594.3 kg/hm^2,喷施6-BA 11.8 mg/L,预期产量为6629kg/hm^2。

【Objectives 】 Ninety percent of dry matter in millet is from photosynthesis. So it is important to maintain high and durable photosynthetic efficiency of the upper blades for the formation of high yield. The study of the appropriate application rate of N,P and plant growth stimulator for the highest photosynthetic efficiency in foxtail millet will provide a basis for rational fertilization in millet production. 【Methods】Millet cultivar Zhangzagu5 was used as test materials in a field experiment,two general rotating combination design was used for the experiment with 3 replications. Five N levels of 22,69,138,207,254 kg / hm2,and five P2O5 levels of 11,36,72,108,133 kg / hm2 were basal applied,and cytokinin 6- BA [0. 5%（ v / v） ] was foliar sprayed since the start of flowering period and the spray was conducted at 16： 00 pm in intervals of 4 days. The chlorophyll content,net photosynthetic rate,leaf area index of the flag leaves and the yield were measrued. 【Results】The single level of phosphate and cytokin 6- BA all have significant effects on leaf area index,net photosynthetic rate,chlorophyll contents,and yield of millet,and the four indices have a trend from rising to declining with phosphate and cytokin6- BA all increasing. The nitrogen level has great effect on net photosynthetic rate,leaf area index and yield,and the three indices are increased at first and then decreased with the increase of nitrogen level. The levels of nitrogen,phosphate and cytokin 6- BA all showed significant effects on yield,and the yield was mainly affected by phosphate level,and less affected by nitrogen and cytokin 6- BA. The interactions between nitrogen and cytokin 6- BA level show significant effects on leaf area index,net photosynthetic rate,chlorophyll contents,and yield of millet. This combination of nitrogen and cytokin 6- BA could improve photosynthesis and yield,and exhibit great potentials for practical application. 【Conclusions】The appropriate nitrogen and phosphate levels combined with foliar spray of 6- BA show significant increase effect on leaf area index,photosynthetic efficiency and yield of millet,over the levels will lead to significant decrease effect. The regression relationship between the levels of nitrogen,phosphate,and cytokin 6- BA and the yield of Zhangzagu 5 can be used for production forecasts. The recommended level for Zhangzagu 5 is N 175 kg / hm2,P2O594. 3 kg / hm2,cytokin 6-BA 11. 8 mg /L under the experimental conditions with the expected yield of 6629 kg / hm2.