INFLUENCE OF WHEAT STRAW AND RHIZOSPHERE ON SEED GERMINATION, EARLY SEEDLING GROWTH AND BIO-CHEMICAL ATTRIBUTES OF Trianthema portulacastrum 1 Influência de Palha de Trigo e Rizosfera sobre a Germinação de Sementes, Crescimento Precoce das Mudas e Atributos Bioquímicos do Trianthema portulacastrum

ABSTRACT - Decomposing wheat (Triticum aestivum) straw and rhizosphere-infested soil wereevaluated for their suppressive activity against horse purslane (Trianthema portulacastrum), anoxious summer weed in Pakistan. Two separate pot studies were carried out. Wheat strawwas incorporated at 4, 6 and 8 g kg -1 soil five days before the sowing of horse purslane. Potswithout straw incorporation were maintained as control. In a second study, soil was takenfrom 15 and 30 cm depths from a previously cropped wheat field immediately after its harvestand was used as growing medium. Soil from an intentionally uncropped area of the samefield was used as control. Suppressive activity was measured in terms of germination dynamics,seedling growth, and biochemical attributes such as chlorophyll contents, total solublephenolics, soluble protein and antioxidant enzymes. Germination, seedling growth, chlorophyllcontents and soluble protein of horse purslane were all negatively influenced. Higher phenolicsand enhanced activities of antioxidant enzymes were noticed in response to wheat residuesincorporation and its rhizosphere soil. Both studies established that the phytotoxic influenceof wheat straw and wheat-infested rhizosphere soil on horse purslane can further be exploitedfor horse purslane management as a sustainable approach.Keywords: allelopathic rhizosphere, chlorophyll, phenolics, antioxidants.RESUMO - Restos culturais de trigo ( Triticum aestivum) em decomposicao e o solo da rizosferaforam avaliados quanto a supressao da atividade contra Trianthema portulacastrum , uma plantadaninha de verao comum no Paquistao. Dois estudos independentes foram realizados em vasos.Palha de trigo foi incorporada ao solo em taxas de 4, 6 e 8 g kg