Efeito da luz na germinação e desenvolvimento de plântulas de pinhão-manso (Jatropha curcas L.) de distintas procedências

Abstract

Light effects on germination and early development of physic nut (Jatropha curcas L.) from distinct geographical provenances). Studies about the influence of light on the germination and early development are important to cultivate physic nut in the field. The aim of this study was to evaluate the light effect on the seed germination of physic nuts from distinct geographical provenances and to examine the morphology of seedlings. The first germination bioassay was accomplished in a dark chamber and the second in the presence of light (32 µmol m -2 s -1 ) with a daily photoperiod of 12 hours. There was no significant difference in the percentage of seed germination between of the seeds of the studied lots. The percentage of germination was high in all lots (in the dark or under light), being the seeds classified as neutral photoblastic. In the dark, the seedlings had a greater number of emerged and opened cotyledons, length of hypocotyl-root axis, and growth rate. These results are explained by etiolation of seedlings, germinated in the dark. However, under the light, there was a darkening of seedlings, which impaired impairing its development.

Effect of Drying Temperature in the Physiological Quality of Jatropha curcas Seeds

“…In the present study, the results were similar to those verified by Silva, Hisatugo, and Souza, (2016), up to 45 °C, that studying the effect of light on the germination of jatropha seeds of different provenances, verified that there was no difference in the percentage of germination between the seeds of the lots studied and that the average percentage of germination found for the seeds of jatropha (77%) is considered high. Vanzolini, Meorin, Da Silva, and Nakagawa (2010) and Martins, Machado, and Cavasini (2008) found similar results, where jatropha seeds germinated between 70 and 87%.…”

Fruit and seeds biometry and germination of Psidium cauliflorum Landrum & Sobral

“…The absence of light led to etiolation, agreeing with that observed for J. curcas (Silva et al, 2016). Moreover, there was lower root growth as a result of the respiration process and the plant energy spent in the search for light (Silva et al, 2016).…”

Influence of light, temperature and humidity on substrate and osmoconditioning during the germination of Mimosa bimucronata (DC) O. Kuntze.

“…The seeds of M. bimucronata are germinated both in the presence and absence of light and could be classified as neutral photoblasts, neutral to light in seed germination. According to Silva et al (2016), neutral photoblasts refers to a behavior commonly described for the understory trees and shade plants.…”

“…Among the environmental factors, light and temperature are known to greatly influence germination, affecting both the rate of water absorption and the biochemical reactions that trigger the process. The sensitivity of seeds to light can be altered by several factors such as age, temperature, plant growth conditions, and water (Matos et al, 2015;Silva et al, 2016). Their presence can help reduce the problems caused by low amount of water in the soil and the effect of higher temperatures, promoting or inhibiting the germination process, with varying responses according to the species and depending on the luminous environment surrounding them (Galindo et al, 2012;Pacheco Jr et al, 2013).…”