Vateria indica L. is a critically endangered tree species in South-Western Ghats of India, commercially exploited for its valuable resins. Seed recalcitrance is a major problem hindering the natural regeneration of this species and it poses a great challenge in seed storage and conservation. There was a continuous import of water from the maternal tissues to seed tissues till maturity and the seeds were released in a fully hydrated state. Differential accumulation of water has been noticed in the cotyledons and embryonal axis. There was a positive correlation between seed moisture content and rate of germination which is a character of recalcitrant seeds. The critical moisture content was found to be 40% in the axis and 23.5% in the cotyledons, below which the embryo will not germinate. Loss of germination ability as a result of desiccation was attributed to the cell membrane damage, expressed as the electrolyte leakage exceeding 0.79 μS/cm. ABA peaked in the mid embryogenesis, then dropped drastically and maintained a lower level till seed maturity. On desiccation, ABA started to increase but gradually dropped down. Both cotyledons and embryonal axis had differential ABA content but exhibited a general pattern of ABA level during embryogeny. Due to the thin seed coat/embryo ratio and low investment in the seed coat, this recalcitrant seed could not hold water as efficient as orthodox seeds. Thus, it germinated as soon as it was shed from the mother plant. On desiccation, ABA shot up and moisture content decreased along with electrolyte leakage and cell membrane damage. All these hindered germination of the seed. Thus, we can see a clear interplay between moisture content and ABA levels during embryogeny and desiccation. Since the seed biology of this species has not been well documented, the present work is mainly intended to study the dynamics of water and ABA during embryogeny and embryo drying. This study can surely contribute to the long-term storage and conservation of recalcitrant seeds which is a less explored area.

中文翻译：

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黄芪顽固种子胚胎发生和胚胎干燥过程中水分和脱落酸的动态变化。

Vateria indica L. 是印度西南高止山脉的一种极度濒危的树种，因其有价值的树脂而被商业开发。种子顽固性是阻碍该物种自然更新的主要问题，对种子储存和保护提出了巨大挑战。水从母体组织不断输入到种子组织直到成熟，种子以完全水合的状态释放。在子叶和胚胎轴中已经注意到水的差异积累。种子含水量与发芽率呈正相关，这是顽固种子的特征。发现轴上的临界水分含量为 40%，子叶中的临界水分含量为 23.5%，低于此值胚胎将不会发芽。由于干燥导致发芽能力丧失归因于细胞膜损伤，表现为电解质泄漏超过 0.79 μS/cm。ABA在胚胎发生中期达到峰值，然后急剧下降并保持较低水平直至种子成熟。干燥时ABA开始增加但逐渐下降。子叶和胚轴都具有不同的 ABA 含量，但在胚胎发生过程中表现出 ABA 水平的一般模式。由于种皮/胚比薄且种皮投资低，这种顽固的种子不能像正统种子那样有效地保持水分。因此，它一从母株上脱落就发芽了。在干燥过程中，ABA 增加，水分含量降低，同时电解质泄漏和细胞膜损伤。所有这些都阻碍了种子的发芽。因此，我们可以看到胚胎发生和干燥过程中水分含量和 ABA 水平之间的明显相互作用。由于该物种的种子生物学尚未得到很好的记录，目前的工作主要旨在研究胚胎发生和胚胎干燥过程中水和 ABA 的动态。这项研究肯定会有助于顽固种子的长期储存和保护，这是一个探索较少的领域。