Nitric oxide affects phosphorus redistribution and senescence in soybean leaves during P starvation

ROCÍO MATEOS; IGNACIO DELGADO; SANTA-MARÍA, GE; SIMONTACCHI, M

Buenos Aires

Congreso; VIII International Congress Society for Free Radical Biology and Medicine South American Group; 2013

Phosphorus (P) is an essential macronutrient, which usually acts as a limiting factor in plant growth and productivity. The influence of NO supplementation, known as a regulator of many aspects of plant physiology, was evaluated through the course of P deficiency in soybean plants. Seven-day-old plants cultured in nutrient solution were exposed to either adequate P supply (0.5 mM H3PO4) or P starvation (without addition of P) for three weeks. P-deficient plants were treated with S-nitrosoglutathione (GSNO) added in the nutrient solution. Leaf functionality was evaluated through chlorophyll content and quantum yield of photosystem II (PSII).P content was determined spectrophotometrically. In the oldest leaves, P concentration dropped from 14±1 µg g-1 FW to 0.49±0.05 µg g-1 FW during P starvation. Chlorophyll and PSII also decreased as a consequence of treatment (45 and 54%, respectively compared to control values). P-deficient leaves enhance their P concentration by 50% when 50 µM GSNO was present. Moreover, the addition of NO kept photosynthetic related parameters at the same level founded in well supplied plants. These results suggest a role for NO in preserving photosynthetic activity close to normal values and influencing P remobilization from old to young leaves in plants growing under low P conditions.