191-14 Soybean Plants Affected by Phosphorus and Water Deficiency.

Poster Number 175

See more from this Division: C02 Crop Physiology and Metabolism
See more from this Session: General Crop Physiology & Metabolism: I
Tuesday, November 2, 2010
Long Beach Convention Center, Exhibit Hall BC, Lower Level
Share |

Maria A. Varillas1, Maria N. Fioretti2, Sandra S. Baioni2, Hugo Mirasson3, Marta I. AveldaƱo1 and Roberto Brevedan4, (1)Departamento de Biologia, Bioquimica y Farmacia, Universidad Nacional del Sur, Bahia Blanca, Argentina
(2)Departamento de Agronomia, Universidad Nacional del Sur, Bahia Blanca, Argentina
(3)Facultad de Agronomia, Universidad Nacional de La Pampa, Santa Rosa, Argentina
(4)Universidad Nacional del Sur, Bahia Blanca (Pcia. Bs. As), Argentina
Three experiments were carried out to determine if the effect of water stress on soybean (Glycine max (L.) Merr.) changes with soil P availability, and whether soil water content affects plant P nutrition. Soils used had three levels of P availability (PI: 4,0 , PII: 6,0 y PIII: 10,0 mg kg-1). Treatments included two levels of P supply (HP: fertilized with 96 kg ha-1 of P, and LP: no fertilized) and two levels of water supply (Irrigated: soils kept at field capacity, and Non irrigated: plants were irrigated to field capacity after leaf water potential reached -2.7 MPa). Several water deficient cycles were applied from flowering stage (R2) to beginning of seed-filling (R5). In general, most of the effects of phosphorus and water stress on soybean growth were additive, so, effects of water stress were similar at every P level. Fertilized plants increased their vegetative development: increased shoot growth (10,5%), leaf area (22,1%), P and N concentration (29,2 and 18,8%, respectively), seed size (27,4%) and yield (29,8%). Water stress accelerated seed maturity, reduced shoot growth, leaf area, P and N concentration. Water deficiency caused a large decrease in seed yield but seed weight was not so much affected, showing that soybean response to the dry cycle was mainly due to a reduction in seed number but not seed weight. Soybeans had a positive response to P availability in the three soils, with and without irrigation, suggesting that phosphorus addition would be justified even when a dry growing season is likely to occur.
See more from this Division: C02 Crop Physiology and Metabolism
See more from this Session: General Crop Physiology & Metabolism: I