Growth Response of Rice and Paddy Weeds Under Elevated Temperatures

This study was conducted to investigate the growth response of rice and annual paddy weeds under elevated temperatures. In the context of climate change, temperature is one of the most important climatic factors influencing the growth of crops as well as weeds. Rice and three major annual paddy weeds (Monochoria vaginalis, Echinochloa crus galli, and Ludwigia prostrata) were grown under different temperature regimes (ambient, ambient+0.8 degrees C, ambient+1.9 degrees C, and ambient+3.4 degrees C). Results revealed that the growth of rice and three annual paddy weed species increased with the temperature rise in the phytotrons. Above ground dry weight of rice was 1.31, 1.67, and 1.73 times higher at ambient+0.8, +1.9 and +3.4 degrees C, respectively, than it was at ambient. Similar growth responses to rice was observed in E. crus galli and M. vaginalis under the elevated temperatures. L. prostrate exhibited the most significant increases in leaf stage, leaf area, plant height, and plant dry weight, which were, respectively, 2.94, 3.57, 1.69 and 2.86 times higher at ambient+3.4 degrees C than at ambient. Our findings suggest that climate change in the form of instant rising of temperatures might have an influence on the growth of rice and weeds and might confer relatively low competitive ability to rice.