Data/hora: 21/06/2024 01:07:05

Biblioteca(s): 	Embrapa Cerrados; Embrapa Trigo.	
Data corrente: 	18/12/1995	
Data da última atualização: 	29/11/1999	
Autoria: 	MIRANDA, L. N. de.	
Título: 	Aluminium - phosphate interactions in relation to wheat growth.	
Ano de publicação: 	1985	
Fonte/Imprenta: 	[Reading]: University of Reading, 1985.	
Páginas: 	169p.	
Idioma: 	Inglês	
Notas: 	Ph.D.Thesis.	
Conteúdo: 	The effects of al on plant growth and nutrient uptake of wheat varieties with different degrees of sensitivity to aluminium were studied, as well as the Al interferences with P translocation within the plant ans the P chemical status in the plant root. This research also studied the effects of lime on plant growth and on plant nutrient uptake  efficiency and investigated the plant's ability to use P to promote root grawth in an acid subsoil with aluminium. In sand culture with Al plant yield was closely related to P inflow. The wheat varieties differed mostly in the Al:P inflow ratio and for the same amount of Al taken up the Al-tolerant varieties absorbed two to four times more P. Liming am acid soil reduced the uptake of Al, improved plant growth and increased the plant uptake of P and K per unit of root length for both Al-tolerant and -sensitive wheat varieties. In the absence of lime the plantas had a higher content and concentration of P in the roots than in the shoots. Also for each mol of Al taken up the Al-tolerant plants absorbed three times more P than the Al-sensitive variety. In nutrient solution without Al, the Al-tolerant variety produced maximum yield at lower P supply and also absorbed more P and translocated more P to the shoots than the Al-sensitive variety. For plants with high root P content, Al reduced P translocations to the shoots and for plants with low root P, Al promoted a downward movement of P from the shoots to the roots. The P retained in the plant roots increased linearly with root Al content, and it was partially exchangeable with P from the external medium. Root P was mostly located in the cell cytoplasm while Al was equally distributed between root cell walls and cell cytoplasm. With the retained in the roots due to Al was translocated to the shoots. Also the uptake of P was smaller according to the previous Al leves for the Al-sensitive wheat variety. In soil columns simulating different topsoil and subsoil conditions the wheat varieties had their growth reduced by subsoil acidity. Shoot growth and subsoil root growth were increased by liming the subsoil but they were limited by the low soil P level. Addition of phoshorus in the topsoil promoted shoot growth and root growth in both soil layers regardless of the subsoil acidity. P was translocated to the roots growing in the subsoil and seem to have romoved Al restrictions by rendering Al harmless within the plant roots.	
Palavras-Chave: 	Aluminium; Growth; Nutrient; Wheats.	
Thesagro: 	Absorção; Alumínio; Calagem; Crescimento; Fisiologia Vegetal; Fósforo; Solo; Trigo; Triticum Aestivum.	
Thesaurus Nal: 	liming; nutrient uptake; phosphates; plant physiology; soil.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Cerrados (CPAC)	
Exemplares: 	CPAC - (16054-1) - ADD - TS - -- - T040/85 - MIR - T040/85 - DIS
CNPT - (30146-1) - ADD - TS - -- - TS-0566 -  - 0566 - DIS