GA3和6-BA对核桃果壳发育的影响

Effect of GA3 and 6-BA on the Development of Walnut Shell

核桃(Juglans regia)薄壳品种的裂果和露仁问题影响坚果及种仁的品质。为了研究果壳发育与植物激素的关系,为调控果壳发育提供理论依据,以‘赞美’(厚壳类型)和‘辽核2号’(薄壳类型)核桃为试材,通过Wiesner染色法研究其果壳的发育过程,对硬核关键时期的IAA、GA、ZR和ABA含量进行了测定;以‘清香’(中等壳厚类型)核桃为试材,用不同浓度6-BA、GA3以及GA合成抑制剂多效唑(PAC)处理幼果,对成熟果实果壳外观形态、内部结构和组分进行了观察分析。结果表明:‘赞美’和‘辽核2号’坚果硬壳发育分别始于花后45和51 d,花后60 d坚果果壳均初步成型,此后果壳内木质素逐渐沉积。硬核期内果皮的GA、IAA、ZR含量整体呈下降趋势,ABA含量呈先降后升趋势。50mg·L^-1 GA3处理‘清香’幼果后,其果壳石细胞层和纤维化细胞层厚度增大,硬壳变厚,缝合线紧密度增强,100 mg·L^-1 PAC处理使石细胞层、厚壁化细胞层和纤维化细胞层均减小,木质素和酚类物质含量下降,硬壳变薄,缝合线紧密度下降;100 mg·L^-16-BA处理后坚果纵径、横径和棱径均显著变小,但果壳结构并未改变。综上,‘辽核2号’坚果果壳发育晚于‘赞美’,50 mg·L^-1 GA3处理‘清香’后果壳(石细胞层)增厚,而100mg·L^-1PAC抑制果壳(石细胞层、厚壁化细胞层和纤维化细胞层)增厚,说明GA参与了果壳发育的调控过程;100 mg·L^-16-BA处理后坚果变小但果壳结构无显著变化。

The dehiscent nut and incomplete hulls of thin-shelled walnut(Juglans regia)seriously influenced the quality of nuts and kernels.In order to explore the relationship between the development of nut shell and phytohormones,and to provide a theoretical basis for regulating the nut shell development.In this study,’Zanmei’(thick-shell cultivar)and’Liaohe 2’(thin-shell cultivar)walnut as material,the development of thin-shell and thick-shell nut shell was studied by Wiesner raction.IAA,GA,ZR and ABA contents were determined during the process of shell differentiation.’Qingxiang’(moderate thickness shell cultivar)walnut as material,the characteristic,structure and components of mature nutshell were evaluated after treated by 6-BA,GA3 and paclobutrazol(PAC,a specific inhibitor of gibberellin biosynthesis)at different concentrations during shell development.The results showed that the shell development of’Zanmei’and’Liaohe 2’began at 45 days and 51 days after anthesis(DAF)respectively and the nut shell initially formed at 60 DAF,and then lignin within the shell deposited gradually.In pericarp,the GA,IAA and ZR content of decreased,and ABA content decreased firstly and then increased during the period of shell differentiation.50 mg·L^-1 GA3 increased the thickness of the stone cell layer and fiber-cell layer,thickened the shell,enhanced suture force grade,and 100 mg·L^-1 PAC decreased the contents of lignin and polyphenol with the thinner of sclereid layer,sclerenchymatous cell layer and fiber-cell layer.100 mg·L^-16-BA treatment decreased the longitudinal diameter,transverse diameter and side diameter of nuts significantly,but there was no change in the structure of the shell tissue.Conclusion:Shell development of’Zanmei’was earlier than that of’Liaohe 2’.For’Qingxiang’,50 mg·L^-1 GA3 increased the thickness of sclereid layer,and 100 mg·L^-1 PAC inhibits the thickening of nut shell,indicating that GA is involved in the regulation of nut shell development.The nut became smaller after treated by 100 mg·L^-16-BA,but there was no change in the structure of shell tissue.