Key Laboratory of Grassland Ecosystems, College of Grassland Science, Gansu Agricultural University, Lanzhou, 730070, China.
Tibet Grassland Science Research Institute, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, 850000, China.
BMC Plant Biol. 2024 Jun 11;24(1):530. doi: 10.1186/s12870-024-05221-2.
Seed aging, a natural and inevitable process occurring during storage. Oats, an annual herb belonging to the Gramineae family and pooideae. In addition to being a healthy food, oats serve as ecological pastures, combating soil salinization and desertification. They also play a role in promoting grassland agriculture and supplementing winter livestock feed. However, the high lipid and fat derivatives contents of oat seeds make them susceptible to deterioration, as fat derivatives are prone to rancidity, affecting oat seed production, storage, development, and germplasm resource utilization. Comparative studies on the effects of aging on physiology and cytological structure in covered and naked oat seeds are limited. Thus, our study aimed to determine the mechanism underlying seed deterioration in artificially aged 'LongYan No. 3' (A. sativa) and 'BaiYan No. 2' (A. nuda) seeds, providing a basis for the physiological evaluation of oat seed aging and serving as a reference for scientifically safe storage and efficient utilization of oats.
In both oat varieties, superoxide dismutase and catalase activities in seeds showed increasing and decreasing trends, respectively. Variance analysis revealed significant differences and interaction in all measured indicators of oat seeds between the two varieties at different aging times. 'LongYan No. 3' seeds, aged for 24-96 h, exhibited a germination rate of < 30%, Conductivity, malondialdehyde, soluble sugar, and soluble protein levels increased more significantly than the 'BaiYan No. 2'. With prolonged aging leading to cell membrane degradation, reactive oxygen species accumulation, disrupted antioxidant enzyme system, evident embryo cell swelling, and disordered cell arrangement, blocking the nutrient supply route. Simultaneously, severely concentrated chromatin in the nucleus, damaged mitochondrial structure, and impaired energy metabolism were noted, resulting in the loss of 'LongYan No. 3' seed vitality and value. Conversely, 'BaiYan No. 2' seeds showed a germination rate of 73.33% after 96 h of aging, consistently higher antioxidant enzyme activity during aging, normal embryonic cell shape, and existence of the endoplasmic reticulum.
ROS accumulation and antioxidant enzyme system damage in aged oat seeds, nuclear chromatin condensation, mitochondrial structure damage, nucleic acid metabolism and respiration weakened, oat seed vigor decreased. 'LongYan No. 3' seeds were more severely damaged under artificial aging than 'BaiYan No. 2' seeds, highlighting their heightened susceptibility to aging effects.
种子老化是一种自然且不可避免的过程，发生在储存期间。燕麦是禾本科植物，属于禾本科植物。除了作为一种健康食品外，燕麦还可以作为生态牧场，抵御土壤盐碱化和沙漠化。它们还在促进草原农业和补充冬季牲畜饲料方面发挥作用。然而，燕麦种子中高含量的脂质和脂肪衍生物使其容易变质，因为脂肪衍生物容易酸败，影响燕麦种子的生产、储存、发育和种质资源的利用。关于老化对覆盖和裸露燕麦种子生理和细胞学结构影响的比较研究有限。因此，我们的研究旨在确定人工老化‘龙燕 3 号’（A. sativa）和‘白燕 2 号’（A. nuda）种子劣化的机制，为燕麦种子老化的生理评价提供依据，为燕麦种子的科学安全储存和高效利用提供参考。
在两种燕麦品种中，种子中超氧化物歧化酶和过氧化氢酶的活性均呈先升后降的趋势。方差分析表明，在不同老化时间下，两种燕麦品种的所有测量指标均存在显著差异和相互作用。‘龙燕 3 号’种子老化 24-96 h，发芽率<30%，电导率、丙二醛、可溶性糖和可溶性蛋白水平升高更显著；与‘白燕 2 号’相比。随着老化时间的延长，导致细胞膜降解、活性氧积累、抗氧化酶系统紊乱、胚细胞肿胀、细胞排列紊乱，阻断了养分供应途径。同时，发现核内染色质严重浓缩、线粒体结构受损、能量代谢受损，导致‘龙燕 3 号’种子活力和价值丧失。相反，‘白燕 2 号’种子在老化 96 h 后发芽率为 73.33%，老化过程中抗氧化酶活性始终较高，胚细胞形态正常，内质网存在。
老化燕麦种子中活性氧的积累和抗氧化酶系统的损伤，核内染色质的浓缩，线粒体结构的损伤，核酸代谢和呼吸的减弱，导致燕麦种子活力的降低。人工老化后，‘龙燕 3 号’种子比‘白燕 2 号’种子受损更严重，表明其对老化效应的敏感性更高。
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