山核桃果实成熟过程中矿质元素及脂肪酸组分变化

Dynamic changes in composition of mineral elements and fatty acids for hickory nuts(Carya cathayensis) during maturity

为探明山核桃Carya cathayensis果实发育成熟过程中主要矿质元素、种仁脂肪和脂肪酸的变化特征,以40年生山核桃为试材,对果皮和种仁中氮、磷、钾、钙、镁等主要矿质元素、种仁脂肪和脂肪酸进行了分析测定,并探讨了各组分间的相关性。结果表明:山核桃果实成熟过程中,果实干物质总质量没有显著增加,但果皮干物质大量向种仁转移,其中8月5-20日是种仁干物质快速积累期(从0.62 g·粒-1增长至1.34 g·粒-1)。钾大量从种仁向果皮转移,种仁钾质量分数从8月5日的11.71 mg·kg-1降至9月6日的3.44 mg·kg-1,而果皮钾质量分数从5.70 mg·kg-1升高至9.18 mg·kg-1,种仁与果皮中钾质量分数存在消长变化,拐点为8月17-20日;种仁氮、磷、镁质量分数均高于果皮;果皮和种仁中矿质元素质量分数有一定的相关性。种仁脂肪质量分数先快速上升后缓慢上升,8月5-10日是脂肪快速积累期(从243.20 mg·g-1上升至586.02 mg·g-1)。油酸、亚油酸、棕榈酸是种仁充实过程中脂肪酸的主要成分,三者占脂肪酸总量的92.33%~97.50%。脂肪与棕榈酸和亚麻酸极显著负相关(P<0.01),与油酸显著正相关(P<0.05);具有相近或相同碳链长度的脂肪酸存在较高的负相关关系,其中油酸与亚油酸和亚麻酸极显著负相关(P<0.01)。氮、钾是山核桃果实发育过程中最重要的矿质营养,种仁氮、钾与脂肪酸组分的相关性最高。因此,丰产优质栽培建议施好果实膨大肥。

To clarify changes in composition of mineral elements,oil content,and fatty acid content of kernels during maturity of the hickory(Carya cathayensis)nut,the contents of N,P,K,Ca,and Mg in kernels and pericarps,as well as oil content and fatty acid composition of kernels during the late development and maturation periods of fruits with 40-year-old mature hickory trees were measured.A correlation analysis of these components was also conducted.Results showed that during the maturity period(from August 5th to September 6th),dry matter of total fruits did not increase(P>0.05).The fast accumulation phase of the kernel was from August 5th to August 20th with dry matter of the kernel increasing 116.1%from 0.62 g per nut to 1.34 g per nut),and an amount of organic matter was transferred from the pericarp to the kernel.K was transferred from kernel to pericarp with K in kernels decreasing from August 5th to September 6th from 11.71 mg·kg-1 to 3.44 mg·kg-1;whereas,in pericarps it was increasing from 5.70 mg·kg-1 to 9.18 mg·kg-1(P<0.05).Contents of N,P,and Mg in the kernel was higher than the pericarp.Contents of the main mineral elements in the kernel and pericarp had some correlation.Total oil content increased quickly and then slowed during maturity with the fast accumulation phase from August 5th to August 20th where total oil content went from 243.20 mg·g-1 to 586.02 mg·g-1(P<0.05).Oleic,linoleic,and palmitic were the main fatty acids comprising approximately 92.33%to 97.50%of the total fatty acids in the kernel.The oil content was significantly and positively correlated with the contents of palmitic(r=-0.855,P<0.01)and linolenic(r=-0.931,P<0.01),and was significantly correlated with the content of oleic(r=0.783,P<0.05).Fatty acids which had near or the same number of carbons tended to have a highly positive correlation.The content of oleic was also significantly and positively correlated with the content of linoleic(r=-0.966,P<0.01)and linolenic(r=-0.854,P<0.01).In general,N and K were the key mineral elements for fruit development,N and K contents in the kernel had a high correlation to fatty acid compounds,and it was a suggested that fertilizing in the early kernel filling period was key to achieving high yield and high quality cultivation.