The use of network analysis to uncover homeostatic responses of a drought-tolerant sugarcane cultivar under severe water deficit and phosphorus supply

Autor(es)

Sato, Agnaldo M. ^[1] ; Catuchi, Tiago A. ^[1] ; Ribeiro, Rafael V. ^[2] ; Souza, Gustavo M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Oeste Paulista, Lab Ecofisiol Vegetal, BR-19067175 Presidente Prudente, SP - Brazil

^[2] Ctr Pesquisa & Desenvolvimento, Inst Agron, BR-13012970 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ACTA PHYSIOLOGIAE PLANTARUM; v. 32, n. 6, p. 1145-1151, NOV 2010.
• Citações Web of Science: 11

Resumo

The objective of this study was to identify how changes in the photosynthetic network would be linked to the homeostasis modulation of a drought tolerant sugarcane cultivar subjected to severe water deficit. Moreover, we tested the potential effect of phosphorus supply on the plant physiological responses to drought, because such element is essential to photosynthetic processes. This study was carried out in a greenhouse, where sugarcane plants (Saccharum spp.) cv. RB 86-7515 were grown. One single-node stalk segment was planted in plastic pots (20 L) filled with soil (red-yellow ultisol). Soil fertilization was performed according to the chemical analysis, except for the phosphorus (P) supply. Plants were subjected to the original P concentration in soil (36 mg dm(-3)) or supplied with 50 mg P2O(5) dm(-3) using CaH(4)(PO(4))(2). Plants were irrigated daily until the beginning of drought treatment. After 90 days of shoot emergence, the water deficit was started at the phenological phase II (tillering). Plants were irrigated with the equivalent to 100% (control) or 10% (water deficit) of daily water requirement based on the evapotranspiration. Light response curves of leaf gas exchange and other physiological and growth variables were performed in each treatment. Data were subjected to analysis of variance and the mean values were compared by Tukey's test (p < 0.05). To assess changes in system network, we evaluated the occurrence of photosynthetic system modulation under distinct water regimes and phosphorus supplying via the concept and measurement of global connectance, C (g). Set of results from coefficient of variation (CV) and C (g) analyses indicated adjustments in the relationships among the elements of the leaf gas exchange network that support the high drought tolerance of the sugarcane cultivar RB 86-7515 and such adjustments enabled the homeostasis of both photosynthesis and plant growth under water deficit. Moreover, P supply improved the sugarcane acclimation capacity by affecting plant characteristics related to water status and photosynthetic performance and causing network modulation under water deficit. (AU)

• Processo FAPESP: 03/06939-5 - Variações sazonais e tolerância à deficiência hídrica de mudas de espécies tropicais arbóreas de diferentes grupos sucessionais
• Beneficiário: Gustavo Maia Souza
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores