Author(s)

Marites A. Sales, Nilda R. Burgos, Vinod K. Shivrain, Brad Murphy, Edward E. Gbur

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Red rice (Oryza sativa L.), a noxious weed in rice production, competes with cultivated rice for nutrients. Accumulation of more N in red rice than in cultivated rice may be due to a mechanism different from that of cultivated rice. To test this assumption, red rice and cultivated rice were grown in nutrient solution to compare their growth and physiological responses to N supply. Experimental design was a split-plot, where main plot factor was rice type (Stf-3, ‘Wells’); split-plot factor was N treatment [T₁ (complete nutrient solution); T₂ (–NH₄NO₃); T₃ (+NH₄NO₃ for 24-h post-N deficiency); and T₄ (+NH₄NO₃ for 48-h post-N deficiency)]. Nitrogen deficiency was defined as N sufficiency index (NSI) < 95%. Height, tiller number, biomass, and root morphology were monitored to determine morphological responses. Stf-3 red rice had significantly greater growth measurements than Wells in terms of shoot and root characteristics. At T₄, Stf-3 showed higher increment in root length and surface area than Wells. Shoot tissue concentrations of N and total sugars were measured to determine physiological response in N-deficient and N-supplemented plants. Stf-3 had greater N and sucrose tissue concentrations at N-deficient conditions compared with Wells, implying a stress-adaptive molecular mechanism regulated by N and sucrose availability.

Hydroponics, Nitrogen Concentration, N Uptake, Rice (Oryza Sativa L.), Root Morphology, Sucrose Concentration, Sugars

M. Sales, N. Burgos, V. Shivrain, B. Murphy and E. Gbur, "Morphological and Physiological Responses of Weedy Red Rice (Oryza sativa L.) and Cultivated Rice (O. sativa) to N Supply," American Journal of Plant Sciences, Vol. 2 No. 4, 2011, pp. 569-577. doi: 10.4236/ajps.2011.24068.