TITLE:
Morphological and Physiological Responses of Weedy Red Rice (Oryza sativa L.) and Cultivated Rice (O. sativa) to N Supply
AUTHORS:
Marites A. Sales, Nilda R. Burgos, Vinod K. Shivrain, Brad Murphy, Edward E. Gbur
KEYWORDS:
Hydroponics, Nitrogen Concentration, N Uptake, Rice (Oryza Sativa L.), Root Morphology, Sucrose Concentration, Sugars
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.2 No.4,
October
31,
2011
ABSTRACT: 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) 4, 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.