Paulo Souza Medri

Morfoanatomia de órgãos vegetativos de plantas juvenis de Aegiphila sellowiana Cham. (Lamiaceae) submetidas ao alagamento do substrato

In order to uncover the morpho-anatomical responses of tree species to hypoxia, we studied the effects of flooding on vegetative organs of Aegiphila sellowiana. Young individuals were kept in drained and flooded soil for 50 and 80 days. Under flooding, there was a mortality rate of 40%. The surviving plants produced peridermic fissures, superficial roots and hypertrophied lenticels. Secondary roots of flooded plants presented greater diameter, thicker cortex, greater diameter of the cortical cells, larger intercellular spaces, and thinner vessel elements and vascular tissues. In the main roots under secondary growth and hypocotyls, cork and phelloderm became thicker under flooding. Leaves of flooded plants presented thicker midrib, larger mesophyll, higher number of trichomes and smaller stomata. Considering that part of the plants subject to flooding have died, it is possible to suggest that A. sellowiana is intolerant of soil inundation. However, the surviving plants showed morpho-anatomical modifications that could have conferred some tolerance to them. Thus, the differential tolerance observed among individuals of A. sellowiana indicates a variability of genotypes in the samples used in this study.

O alagamento do solo afeta a sobrevivência, o crescimento e o metabolismo de Aegiphila sellowiana Cham. (Lamiaceae)?

Visando a elucidar aspectos da tolerância a hipoxia, plantas de Aegiphila sellowiana Cham. (Lamiaceae) foram submetidas a diferentes periodos de inundacao. A sobrevivencia, o crescimento, a condutância estomatica e a fotossintese foram avaliados. Houve mortalidade de 33,3% das plantas alagadas. Dentre as 66,7% sobreviventes, a taxa de crescimento relativo (TCR) de raizes, caule, folhas e da planta inteira foi inferior a TCR das plantas cultivadas em solo drenado. As plantas alagadas apresentaram producao de raizes diageotropicas, maior abscisao foliar e baixa producao de novas folhas. O alagamento provocou reducao na condutância estomatica e na taxa fotossintetica. Sugere-se que A. sellowiana possui intolerância ao alagamento do solo.