Determination of the physio-biochemical changes occurring during seed development, maturation, and desiccation tolerance in Moringa oleifera Lam

Abstract

The present study aims to understand the physiological and biochemical changes occurring in Moringa (Moringa oleifera Lam.) seeds from development to maturation. The flowers of ten uniform plants (1.5 years old) were first tagged, and the growth of the pod and seeds was monitored from 7 days after anthesis (DAA) to 70 DAA (maturity) during 2016-17 and 2017-18. Results showed that the moisture content of seeds increased significantly from 14 to 28 DAA. Following that, it decreased gradually from 28 to 49 DAA and drastically from 49 to 70 DAA. The dry weight of the seeds increased substantially until 70 DAA due to increase in carbohydrates, proteins, and oils in developing seed. Seeds acquired germinability at 49 DAA but attained desiccation tolerance only after 56 DAA. Seeds harvested at 70 DAA showed maximum germination, seedling length, seedling dry weight, vigor index-I, vigor index-II, and maximum dry weight. Thus, this stage could be considered as the most suitable stage for harvesting. Furthermore, high dehydrogenase activity and lower electrical conductivity with a decrease in total soluble sugars and total soluble proteins in seed leachate indicate higher vigour and better physiological status of the seed during the later stages of development and maturation. A proper understanding of seed maturity will boost seed-based cultivation, improve seed storability and germination percentage, reduce seed shattering, and promote commercial cultivation.