Data/hora: 18/06/2024 13:59:27

Biblioteca(s): | Embrapa Meio-Norte.
Data corrente: | 14/04/1997
Data da última atualização: | 14/04/1997
Autoria: | TARDIEU, F.
Título: | Growth and functioning of roots and of root systems subjected to soil compaction. Towards a system with multiple signalling?.
Ano de publicação: | 1994
Fonte/Imprenta: | Soil & Tillage Research, v. 30, n. 214, p. 217-243, 1994.
Idioma: | Inglês
Conteúdo: | The effect of soil mechanical impedance on root growth is discussed on several levels from the apex to the root system. At the individual root level, the balance of pressures on the root apex cannot account for observed reductions in root elongation rate. Furthermore, soil mechanical impedance affects the elongation rate of fon-impeded organs, such as leaves or non-impeded roots. A chemical message originating in roots could account for such an effect, probably via changes in cell wall rheological properties in all growing zones of the plant. Changes in carbon allocation could also have a role. At a whole-plant level, indirect effects linked to changes in the plant structure contribute in a major way to the effect of mechanical impedance on root growth. Although only a small proportion of roots o field-grown plants are in contact with compact soil, geometrical characteristics of root systems are considerably affected. In particular, root deepening is delayed and roots tend to have a clumped spatial arrangement. Experimental evidence and modelling suggest that this change in root system architecture could cause water stress, even in relatively wet soil, because of an increase in resistance to the soil-root water flux. As a consequence, root water status and water flux decrease, and stomatal conductance is reduced as a consequence of a chemical message originating in the roots. This socondary message is super-imposed onto the direct message linked to mechanical impedance.
Palavras-Chave: | Caompactacao; Compaction; Elongation rate; Plant growth regulator; Soil mechanical impedance; Water flux.
Thesagro: | Raiz; Solo.
Thesaurus Nal: | stomatal conductance.
Categoria do assunto: | --
Registro original: | Embrapa Meio-Norte (CPAMN)
Exemplares: | CPAMN - (5803-1) - ADC - SP - -- - S 10664 -  - S 10664 - DIS