高产滴灌春小麦茎鞘非结构碳水化合物代谢及其对产量的贡献

Metabolism of Unstructured Carbohydrates in High Yield Drip Irrigated Spring Wheat and Its Contribution to Yield

为明确新疆焉耆地区高产滴灌春小麦不同茎节茎鞘非结构碳水化合物(NSC)向籽粒转运的水氮响应机制,采用裂区试验设计,以高产小麦品种新春38号(XC38)、新春45号(XC45)为材料,亏缺灌溉(W_(1),4500 m^(3)·hm^(-2))和适宜灌溉(W_(2),6000 m^(3)·hm^(-2))为主区,施氮量N 0(0 kg·hm^(-2))、N_(1)(300 kg·hm^(-2))、N_(2)(400 kg·hm^(-2))为副区,分析了不同处理滴灌春小麦穗下节、倒二节、其余茎节中果聚糖(DP≥4)、蔗糖和NSC的积累、转运特性及其对产量的贡献。结果表明,随生育期的推移,两品种各茎节茎鞘中蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)和蔗糖果糖基转移酶(SST)活性、果聚糖(FC)、蔗糖(SC)和NSC含量均呈先升高后降低的趋势,果聚糖外切水解酶(FEH)活性则呈现降低趋势,SPS、SS活性和SC含量均以W_(1)N_(1)处理最优,其他指标以W_(2)N_(1)处理表现最优。不同茎节相比,其余茎节中果聚糖、蔗糖含量及其代谢酶活性、NSC含量最大,其NSC对产量的贡献率比倒二节、穗下节分别高23.12%~26.42%,70.43%~85.43%。两品种比较,XC45茎鞘中贮藏物质转运率高于XC38,其NSC对产量贡献率比XC38高1.36%~24.70%。产量与SPS、SS、FEH和SST活性及SC、FC、NSC含量均呈显著正相关;SC含量与SPS、SS活性均呈显著正相关,FC含量与FEH、SST活性均呈显著正相关。FC、NSC含量和SS活性对产量的正效应最大;增加NSC、FC含量和SST活性,降低SC含量和SPS活性,可提高两品种产量。水氮互作对NSC花前、花后转运率及其对产量的贡献率的影响显著,且NSC花前转运率及对产量的贡献率大于花后。在本试验条件下,灌水量6000 m^(3)·hm^(-2)和施氮量300 kg·hm^(-2)有利于滴灌春小麦茎鞘NSC代谢、产量形成。

To clarify the water and nitrogen response mechanisms of high-yield drip irrigated spring wheat to the unstructured carbohydrates(NSC)in different stem and sheath nodes in the Yanqi Basin,a split plot experimental design was adopted,with Xinchun 38(XC38)and Xinchun 45(XC45)as materials,deficit irrigation(W_(1),4500 m^(3)·hm^(-2))and suitable irrigation(W_(2),6000 m^(3)·hm^(-2))as the main plots,and N 0(0 kg·hm^(-2)),N_(1)(300 kg·hm^(-2)),and N_(2)(400 kg·hm^(-2))as sub plots,a comparative analysis was conducted on the accumulation and transport of fructose(DP≥4),sucrose,and NSC in the peduncle,top second internode,and other internodes of high-yield drip irrigated spring wheat,as well as their contributions to yield.The results showed that as the growth period progressed,the activities of sucrose phosphate synthase(SPS),sucrose synthase(SS),sucrose glycosyltransferase(SST),fructose content(FC),sucrose content(SC),and NSC content in the stem sheaths of the two varieties at each node all showed an increasing and then decreasing trend,while the activity of fructose hydrolytic enzyme(FEH)showed a decreasing trend.The optimal treatment for SPS,SS activity,and SC was W_(1)N_(1).The other indicators showed the best performance under W_(2)N_(1)treatment.Compared with other nodes,the content of fructose and sucrose,as well as their metabolic enzyme activity and NSC content,were the highest in the remaining nodes.The contribution rate of NSC to yield in other internodes was 23.12%-26.42%and 70.43%-85.43%higher than that in the top second and peduncle,respectively.Compared with XC38,XC45 has a higher accumulation and transportation efficiency of storage substances in its stem and sheath,and its NSC contribution rate to yield is 1.36%-24.70%higher.Correlation analysis showed that there is a significantly positive correlation between yield and SPS,SS,FEH,SST activity,as well as SC,FC,NSC;SC is significantly positively correlated with SPS and SS activity,while FC is significantly positively correlated with FEH and SST activity,indicating that the activity of SPS,SS,FEH,and SST affects SC and FC.Path analysis shows that FC,NSC,and SS have the greatest positive effect on yield.For XC38,increasing the activities of FC,NSC,and SS while reducing the activities of SPS and SST can increase yield.For XC45,increasing SS activity,NSC and FC,and reducing SC and SPS activity can increase yield.The interaction between water and nitrogen has a significant impact on the transport rates of NSC before and after flowering,as well as their contribution to yield,and the transportation rates of NSC before and after flowering are greater than those after flowering.Under the conditions of this experiment,the irrigation amount of 6000 m^(3)·hm^(-2)and the nitrogen application amount of 300 kg·hm^(-2)are beneficial for the metabolism of stem and sheath NSC and yield formation of spring wheat under drip irrigation.