Physiological basis of phenolics phytotoxicity from sugarcane straw

SAMPIETRO, D.A.; VATTUONE, M.A.; ISLA, M. I.

Tucumán (Argentina)

Congreso; XXII Annual Scientific Meeting of Tucuman Biology Society; 2006

Tucuman Biology Society (publicado en Bio Cell 30 (1), 181, 2006)

Postharvest sugarcane residues can inhibit weed growth. Previous studies showed that this material contains phenolics such as vanillic (VA), ferulic (FA) and syringic (SA) acids. The aim of this work was to evaluate the effect of these compounds on the growth of Lactuca sativa L. and four weeds. The effect of these compounds on physiological processes of L. sativa was also determined. Phenolics inhibited root growth of the test plants. These compounds increased membrane permeability and reduced dehydrogenase activity of the root cells of L. sativa. They also reduced chlorophyll content of the cotyledons. VA and FA inhibited cell division while SA stimulated it. Scanning electron microscopy of root tips indicated that VA increased root hair density and reduced cell expansion. Root cell membrane would be the first phenolics action site. The loss of organic and inorganic compounds from root cells could change cell expansion and reduce the energetic metabolism leading to a reduction in cell division. Changes in root cells would produce other modifications such as the inhibition in chlorophyll synthesis. More studies are in progress to establish the impact of phenolics in sugarcane agroecosystem.