钾素对胡麻木质素代谢的调控及其抗倒伏功能研究

According to lignin metabolism regulation after potassium rational utilization and improving lignin content and morphology, crop lodging resistance was improved in its production. Along potassium content and period application gradient, it is to be revealed that lignin synthesis and distribution characteristics adapting to fertility habitat under potassium effection. Oilseed flax is an important oil crop and economic crop in temperate regions of the world, however, contradiction are becoming more prominent between high yield obtaining and lodging serious under adequate water and fertilizer field conditions. In this study, variety of “Longya 11” and “Dingya 23” as the research objects, field experiments were conducted to elucidate gene expression of 4CL1and F5H1, enzyme activity of PAL and so on, lignin content and its microscopic distribution in stem xylem and phloem, lodging index among mechanics, nutrition and yield under potassium application and corresponsive cultivation measures. The laws were revealed that: (1) difference among critical genes and related enzymes, and temporal and spatial distribution; (2) relationships were emonstrated between lodging resistance characteristics and lignin metabolism under potassium regulation; (3) mechanisms that lodging resistance of oilseed flax stalk were elucidated under potassium application. The study intend to recognize the regulatory mechanisms by potassium efficient and rational utilization, also provide abundant theoretical support for lodging resistance in linum plants.

通过钾素合理利用对作物木质素代谢的调节，改善茎秆木质素含量及结构形态，是作物提高其抗倒性的重要途径之一。但随钾肥使用量和时间梯度，茎秆木质素合成及分布特征是否以一定规律应对钾素作用后的肥力生境，有待揭示。胡麻是世界温带地区重要的油料和经济作物，其高产获得与“高肥水”条件下倒伏程度加重之间的矛盾日益突出。本项目通过研究不同倒伏特性胡麻品种在钾素及相应栽培措施下木质素积累、分布、合成关键酶、关键基因与其倒伏特性之间的关系，揭示木质素合成关键基因、相关酶表达差异及木质素积累时空分布规律，阐明钾素运筹对木质素代谢的调控机制，明确钾素调控后木质素合成积累变化对胡麻抗倒伏的影响机理。旨在进一步认识油用亚麻钾素高效合理利用调节机制，也为亚麻属作物抗倒伏提供更为丰富和合理的理论支撑。

本项目以胡麻高产获得与“高肥水”条件下倒伏严重间的矛盾为背景，通过研究不同倒伏特性胡麻品种在钾素及相应栽培措施下木质素积累、分布、合成关键酶、关键基因与其倒伏特性之间的关系，揭示木质素合成关键基因、相关酶表达差异及木质素积累时空分布规律；阐明钾素运筹对木质素代谢的调控机制，明确钾素调控后木质素合成积累变化对胡麻抗倒伏的影响机理。结果表明：（1）2个品种4CL1与F5H3基因表达量因生育时期和供钾水平存在一定差异。生育后期，4CL1在陇亚11号中高表达，而F5H3在定亚23号中高表达。施钾提升了PAL、TAL、POD和CAD活性，其中，中钾处理提升较为显著。同一施钾水平，不灌水处理S型木质素沉积更多。同一灌水水平，生育前期茎横截面积及韧皮部形成层均在高钾水平下达到最大；生育后期，中高钾处理有利于初生木质部和髓射线向髓腔延伸，S型木质素沉积增加，茎秆充实度增加，钾素对相关木质素代谢酶活性、木质素含量影响均达到显著水平。（2）施钾显著提升了2个品种的抗倒能力，其中，施钾60 kg K2O·hm-2时茎秆强度、抗倒伏指数、茎粗均有所提升。单施钾较灌水及施钾+灌水互作对茎粗影响显著。氮磷肥与钾肥配施后，氮磷素积累量、偏生产力和农学利用率均与胡麻抗倒伏指数呈极显著正相关，氮磷肥利用效率则与抗倒伏指数呈显著负相关。钾素积累量、钾肥利用效率和农学利用率均与抗倒伏指数呈极显著正相关。（3）施钾量在30～90 kg K2O·hm-2范围内，胡麻籽粒产量逐渐增加，其中中高钾水平（60～90 kg K2O·hm-2）促进了植株茎粗及有效蒴果数。施钾、灌水及二者互作与施钾、品种及二者互作对籽粒产量的影响均达到显著水平。该结果为进一步认识油用亚麻钾素高效合理利用调节机制，也为亚麻属作物抗倒伏提供了更为丰富和合理的理论支撑。