Salinity effect on vegetative growth and chlorophyll contents of six dominant weed species in Malaysian coastal rice field

Six weed species (Leptochola chinensis, Echinochloa crus-galli, Echinochloa colona, Jussiaea linifolia, Oryza sativa L. and Cyperus iria) were tested for their salt tolerant traits in terms of vegetative growth and chlorophyll contents. Seven different salinity levels viz. 0 (distilled water), 4, 8, 16, 24, 32, and 40 dS m -1 , were executed in a randomized complete block design (RCBD) with four replications during 2010/2011 at Universiti Putra Malaysia. Injury symptoms by salinity, chlorophyll contents, plant height, shoot, root dry weight and total biomass were measured. There was significant variation between species and different salinity levels for all the characters studied. Injury symptoms appeared after application of salt and the symptoms were more severe at higher saline condition in some species. Chlorophyll contents, plant height, shoot-root dry weight and total biomass were significantly decreased with increasing the salinity levels. Two species (E. crus-galli and C. iria) better performed in terms of vegetative growth, chlorophyll contents and injury symptoms. Two species (E. colona and J. linifolia) were also moderately tolerant while other two species, L. chinensis and O. sativa L. (weedy rice) were weak in withstanding salinity shocks. The presence of salt-tolerant weed species in rice ecosystems appropriate weed control methods to be applied. Hence, special attention should be paid to Echinochloa spp. and Cyperus iria under saline environments.