ความสัมพันธ์ระหว่างศักยภาพทางอัลลีโลพาทีกับการเติบโตของข้าว (Oryza sativa L.) ภายใต้ภาวะเครียด

Abstract

Allelopathy refers to the beneficial or harmful effect of one plant on another plant, both crop and weed species, from the release of biochemicals, known as allelochemicals. Several studies have examined the effects of environmental stress factors such as excess or low light, lack of water, nutrient deficiency, salinity, weed, pathogen and insect on allelochemical release by plants and found that stress factors not only affect growth but also allelopathic potential of plants. This study was divided into two parts. The first part examined the effect of low light and low nutrient stress in Hawm Jan variety rice seedlings. Light experiment was done by growing rice plants under different light conditions, i.e. 100%, 50%, and 10% of full sunlight for 14 days then measuring their growth and allelopathic potential using water extracts and tested with lettuce seeds for three days. The Inhibitory activity of germination, shoot length, root length, and dry weight of lettuce seedlings were measured. Results showed that as light intensity decreased from 100% to 10%, rice growth decreased and its allelopathic potential also decreased. Nutrient experiment was done by growing rice plants under different nutrient solutions, i.e. normal strength, 10 times and 100 times dilutions (1N, 0.1N and 0.01N, respectively) of Hoagland nutrient solution. Rice shoot length, plant dry weight, leaf greenness and maximum quantum yield (Fv/Fm) were measured. Allelopathic potential was tested using lettuce seeds. Inhibitory activity of germination, shoot length, root length, plant length and dry weight of lettuce seedlings were measured. Results showed that as nutrient concentrations decreased from 1N to 0.01N, rice growth decreased while its allelopathic potential increased. In the second part, nutrient stress factor was examined for the relationship between growth and allelopathic potential in three rice varieties, i.e. Hawm Jan, San Suay and Niaw Dam Chaw Mai Pai. The results showed that when the three rice varieties were grown from high to low nutrient concentrations, their growth decreased while allelopathic potential increased. Niaw Dam Chaw Mai Pai tended to have the higest rate of allelopathic potential change under increased nutrient stress condition followed by Hawm Jan and San Suay, respectively.