Physiological responses induced in annual weeds by sugarcane straw

SAMPIETRO D.A.; SGARIGLIA MA.; SOBERÓN J.R.; VATTUONE M.A.

Tucumán - Argentina

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

Tucuman Biology Society (publicado en Bio Cell 31 (2))

Postharvest sugarcane residues suppress growth of annual weeds. Current evidence suggests that organic molecules from sugarcane straw leachates are involved. The aim of this work was to elucidate how straw leachates inhibit weed growth. Straw leachates were incorporated in pots to soil and soil mixed with activated charcoal. Seeds of Bidens subalternans and Brassica campestris were placed in each pot. Leachates of straw ashes were also assayed. Phenolic compounds and proline content were determined. Straw leachates inhibited radicle growth of both weed species. In soil with activated charcoal, weed inhibition was less marked. Leachates of straw ashes were not inhibitory. Straw leachates increased levels of soil phenolic compounds. This Increase was related with higher levels of foliar proline contents and a decline in radicle elongation. Our results suggest that organic molecules directly inhibited radicle length of the assayed weeds. A water imbalance would induce praline accumulation in receptor plants. Although phenolic compounds could induce this response, organic molecules with other chemical natures could not be excluded.