Abstract

Humboldtia vahliana Wight. is an endangered species belonging to the family Leguminosae (subfamily Caesalpinioideae). Though the plant propagates through seeds, low seed setting, seed infestation, poor viability of seed, reduction in natural regeneration of seedlings as well as anthropogenic activities like overexploitation, habitat destruction and fragmented distribution in localities are the major factors hindering the survival of the species. Hence, strategies must be devised urgently for the conservation of this species as these recalcitrant seeds do not contribute significantly to the seed bank. The present attempt was to understand the seed physiology and biochemistry during embryogenesis and embryo desiccation. H. vahliana seeds took 120 days after anthesis to acquire full maturity. Immature seeds had higher moisture content (87.40%) which gradually reduced during maturity and reached 55.42% at the time of seed shed a true recalcitrant behavior of the seeds. Freshly fallen mature seeds showed an optimal germination percentage of 82.32% which was severely affected by the decrease in seed moisture content and the critical moisture content was found to be 33.63% in which the percentage of germination was only 30%. Cell membrane damage of seed was found to cause quick loss of seed viability. The LC-MS/MS analysis showed insignificant amounts of ribose, arabinose and trehalose but a significant accumulation of fructose in the mature embryos rather than glucose and sucrose. Embryo drying significantly reduced the level of these sugars including the stress related trehalose indicating the lack of biosynthetic machinery to counter desiccation stress in these recalcitrant seeds.

中文翻译：

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Humboldtia vahliana Wight 不耐干燥种子胚胎发生和胚胎干燥过程中的水分和糖分状况

摘要

Humboldtia vahliana怀特。是属于豆科（Caesalpinioideae 亚科）的濒危物种。虽然该植物通过种子繁殖，但结实率低、种子为害、种子活力差、幼苗自然更新减少以及过度开发、栖息地破坏和局部分散分布等人为活动是阻碍该物种生存的主要因素. 因此，必须紧急制定策略来保护该物种，因为这些顽固的种子不会对种子库做出重大贡献。目前的尝试是了解胚胎发生和胚胎干燥过程中的种子生理学和生物化学。H. vahliana种子在开花后需要 120 天才能完全成熟。未成熟种子水分含量较高（87.40%），随着成熟期水分含量逐渐降低，种子脱落时达到55.42%，这是种子真正的顽固行为。刚落下的成熟种子的最佳发芽率为 82.32%，受种子水分含量下降的影响较大，临界水分含量为 33.63%，发芽率仅为 30%。发现种子的细胞膜损伤会导致种子活力的快速丧失。LC-MS/MS 分析显示核糖、阿拉伯糖和海藻糖的含量微不足道，但成熟胚胎中果糖而非葡萄糖和蔗糖的显着积累。