Status of Moisture and Sugar during Embryogenesis and Embryo Desiccation in the Desiccation-Intolerant Seeds of Humboldtia vahliana Wight

• Published in: Russian journal of plant physiology 2022-12, Vol.69 (6), Article 124
• Main Authors: Lima Lawrance, S., Sunil Kesava Deth, G., Ajith Kumar, K. G., Raju, Princy, John, Sneha, Nair, S. Parvathy
• Format: Article
• Language: English
• Subjects: Anthropogenic factors; Arabinose; Biomedical and Life Sciences; Cell membranes; Desiccation; Embryogenesis; Embryonic growth stage; Embryos; Endangered species; Environmental degradation; Germination; Habitat loss; Life Sciences; Moisture content; Moisture effects; Overexploitation; Plant Physiology; Plant Sciences; Research Papers; Ribose; Seed banks; Seedlings; Seeds; Sucrose; Sugar; Trehalose; Water content; Wildlife conservation
• ISSN: 1021-4437; 1608-3407
• DOI: 10.1134/S1021443722060176

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.