摘要
为了探讨核桃种子发育过程中油脂、蛋白质和碳水化合物积累之间的关系及油脂积累过程中脂肪酸含量的动态变化，以新疆早实核桃为试材，研究了核桃种子发育过程中油脂积累及其与糖类、蛋白质之间关系。结果表明：油体在核桃花后60d胚的薄壁细胞中出现，而出现在子叶薄壁细胞中的时间为花后80d；胚和子叶薄壁细胞中的油体均于花后100d开始大量增多，并向细胞中心不断积累；花后50～60d子叶细胞中大量出现淀粉粒，70～110d淀粉粒减少，并维持在较低水平。蛋白体在花后70d出现，并在花后70～110d数量不断增加至最大；花后120d后，各种细胞器解体并{肖失，胚和子叶细胞被油体和蛋白体填满。核桃种子发育过程中，油脂含量不断增加，花后70-110d呈明显上升趋势，且与可溶性糖、淀粉含量呈极显著负相关（P〈0．01）。总蛋白质含量在核桃种子油脂快速积累期不断增加，花后90d达到最大值，虽与油脂含量呈正相关，但相关性未达到显著水平（P〉0．05）。在核桃种子发育过程中先后有6种脂肪酸出现，不饱和脂肪酸的相对含量随种子发育时间的推移逐渐增大，饱和脂肪的相对含量则随种子发育时间的推移呈下降趋势；种子成熟时，不饱和脂肪酸中的亚油酸含量最高，油酸、α-亚麻酸含量次之，二十碳烯酸含量最低；油酸、亚油酸的相对含量呈同步变化趋势，而与r亚麻酸的相对含量变化趋势相反。以上结果表明核桃种子发育过程中油脂合成原料物质主要来源于叶片、青皮（外果皮）中光合作用产生的可溶性糖，与蛋白质的积累代谢途径相独立；参与脂肪酸合成的SAD（△9 stearoyl acyl-carrier protein desaturase）. FAD2 （△12 fatty acid desaturase 2）和FAD3 （△12 fatty acid desaturase 3）酶催化活性均较高，但SAD、FAD2酶催化活性较FAD3酶强。
In order to determine the lipid accumulation and its relationship with carbohydrates and protein,and to investigate changes of fatty acids during the seed development period, the precoucious walnut seeds were used as materials in this paper. The results showed that the oil bodies were first observed at the 60^th day after flowering （DAF） in the embryo. The period of oil bodies observed in cotyledon was later than that in embryo. The number of oil bodies in- creased rapidly after 100 DAF both in the parenchyma ceils of embryo and cotyledon. The number of starch grains was accumulated after 50-60 DAF and decreased after 70 110 DAF, following which the number stabled at a low leve. The protein bodies were first observed at the 70th DAF, and then increased gradually during the period of 70-110 DAF. 120 days after flowering , the organelles began to disintegrate and disappear. In the period of seed maturity, the cells of cotyledon and embryo consisted of oil bodies and protein bodies. In the develop- ment of walnut seeds, the lipid content of the seeds increased constantly during the period of 70 110 DAF. The soluble sugr and starch content were decreased. The protein content in- creased rapidly during the period of fast accumulation of lipid in the seeds, and achieved to the maximum at the 90^th DAF. The lipid content significantly and negatively correlated with the soluble sugar and starch content（P〈0.01）, but positively correlated with the protein content （P〉0.05）. Six fatty acids were detected in the development of walnut seeds. Among them, the content of unsaturated fatty acids was increased and the content of saturated fatty acids was decreased with the development of the walnuts. During the period of seed maturity, the linoleic acid content was 63.1%, which was the highest among all the fatty acids, The oleic, linoleic and a-Linolenic exhibited different accumulation patterns. According to the results, the accumulation patterns of lipid, carbohydrates and protein were different, which indicated that the lipid synthesis was achieved largely by soluble sugar directly from the photosynthesis of leaves and peels rather than transiently accumulated starch. The lipid and protein accumulations were independent processes in the developing seed. During the seed development period of the walnut, the oleic acid and linoleic acid accumulated simultaneously and showed significant positive correlation. It suggested that the genes for △9stearoyl acyl-carrier protein desat- urase（SAD） and △12 fatty acid desaturase 2（FAD2） were the major determinants for improving the composition of fatty acids in walnuts.
出处
《河北农业大学学报》
CAS
CSCD
北大核心
2016年第1期57-62,74,共7页
Journal of Hebei Agricultural University
基金
国家自然科学基金(31460210)
关键词
核桃
种子
油脂积累
脂肪酸
淀粉
可溶性糖
蛋白质
walnut
fruit（seed） development
lipid accumulation
fatty acid
starch
soluble sugar
protein
