Data/hora: 23/09/2024 02:06:39

Biblioteca(s): 	Embrapa Meio-Norte.	
Data corrente: 	16/04/1997	
Data da última atualização: 	16/04/1997	
Autoria: 	PETRIE, C. L.; HALL, A. E.	
Título: 	Water relations in cowpea and pearl millet under soil water deficits. III. Extent of predawn equilibrium in leaf water potential.	
Ano de publicação: 	1992	
Fonte/Imprenta: 	Australian Journal of Plant Physiology, v. 19, n. 6, p. 601-609, 1992.	
Idioma: 	Inglês	
Conteúdo: 	Pearl millet [Pennisetum americanum (L.) Leeke] consistently develops lower predawn leaf water potentials than cowpea [Vigna unguiculata (L.) Walp.] when plants are subjected to progressive soil drying, even when they are grown as intercrops in the same pot. Lack of equilibrium in water potential during the predawn, within the plants and between plants and soil, was studied as a possible explanation for this difference. Experiments were conducted in a glasshouse in pots containing an artificial rooting medium which had a high water-holding capacity and was easy to separate from roots. Leaf and root predawn xylem water potentials were measured with a pressure chamber. In cowpea, leaf water potential (wL) values during the dry treatment were similar to values  of root water potential (wR), indicating an approximate equilibrium within the plants. Im millet, measurements were made on plants grown in both large and small pots. With large pots, wL and wR values im millet were similar, but with small pots, predawn wL was lower than wR. When the surfaces of these small pots were covered with evaporation barriers, however, no significant differences developed between wL and wR at predawn during soil drying, indicating an approximate equilibrium within millet. During the early stages of the dry treatment, leaf surface conductances measured at predawn indicated that significant water flux occurred at night from the leaves of both cowpea and millet.	
Palavras-Chave: 	Caupi; Cowpea; Estresse hidrico; Millet.	
Thesagro: 	Milheto; Pennisetum Americanum; Vigna Unguiculata.	
Thesaurus Nal: 	water stress.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Meio-Norte (CPAMN)	
Exemplares: 	CPAMN - (4671-1) - ADC - SP - -- - S 10680 -  - S 10680 - DIS