Morphophysiological profile of Jatropha curcas L. fruits and seeds maturation

Abstract

Jatropha curcas L. (Euphorbiaceae), known as physic nut, is an oil seed species suitable as feedstock for biodiesel production, among other possible industrial applications. It is also considered tolerant to water restriction and is thus suitable for cultivation in semi-arid regions. However, the lack of uniformity in fructification and seed maturation hinders the harvest and processing of fruits and seeds and the yields from both oil and seed, as well as obtaining seed lots with good physiological qualities as propagule. Thus, the aim of this study was to characterise the physiological profile during the development and maturation of J. curcas seeds and to identify the best time to harvest the fruits and seeds based on morphological and physiological aspects. Fruit and seed development was monitored and the fruits were harvested at the end of the maturation phase. Then, they were visually classified in six distinct stages of maturation based on the size and colour of the exocarp, whereas the seeds were classified into 13 distinct stages based on the appearance of the fruit and colour of the tegument. The overall analysis of the parameters indicated that the best harvest time was when the fruits were brown and brown-dry and the seeds presented maximum dry matter accumulation, lower moisture content, the highest germination and vigour, higher lipid content and stable length and width dimensions. Whereas these parameters are related to physiological maturation in J. curcas seeds.