Acclimation responses of macaw palm seedlings to contrasting light environments
sexta-feira, novembro 16, 2018
Authors: Adriel N. Dias, Advanio I. Siqueira-Silva, João P. Souza, Kacilda N. Kuki & EduardoG. Pereira
The photosynthetic adjustments of macaw palm (Acrocomia aculeata) were evaluated in 30-dayold
seedlings exposed to high and low light environments, and sudden transference from low to
high light and comparisons were made with the hardening protocol used in nurseries. Furthermore,
we evaluated the responses to long-term exposure (265 days) to high and low light environments.
Macaw palm seedlings exhibited an efcient mechanism that maximized light capture under scarce
conditions, and dissipated excess energy to avoid damaging to the photosystem II under high light.
The seedlings showed low saturation irradiance but no photoinhibition when exposed to excess
light. When grown under low light intensities, seedlings presented higher photochemical efciency
and minimized the respiratory costs with positive carbon balance at lower irradiance than hardened
seedlings did. The hardening procedure did not appear to be an advantageous method during seedling
production. Long-term exposure to either low or high light did not cause signifcant leaf anatomical
adjustments. However, the low light seedlings showed higher leaf area and chlorophyll content than
those exposed to higher light intensity did, which enabled shaded seedlings to maximize the captured
light. Furthermore, the high non-photochemical dissipation allowed rapid acclimation to excessive
light exposure. These responses allow macaw palm cultivation and establishment in very diferent light
environments.
0 comentários
Agradecemos seu comentário! Volte sempre :)