Growth evaluation and water relations of Erythrina velutina seedlings in response to drought stress

Ano: 2010 | Volume: 22 | Número: 4

Autores: Elizamar Ciríaco da Silva, Marcos F. A. Silva, Rejane J. M. C. Nogueira, Manoel B. Albuquerque

Palavras-chave: biomass allocation, dry matter, leaf area, root to shoot ratio, relative water content, water potential

Resumo Inglês:

Erythrina velutina Willd. (common name: mulungu) is a deciduous, heliophyte found in the semi-arid region of northeastern Brazil. To
evaluate the growth and water relations of mulungu seedlings in soils with different degrees of moisture content, an experiment was
carried out under greenhouse conditions using four water treatments (100%, 75%, 50% and 25% of the field capacity- FC). Predawn
(Ψpdw) and midday leaf water potential (Ψmdw), relative water content (RWC), plant height, number of leaves, stem diameter, leaf area
(LA), specific leaf area (SLA), leaf area ratio (LAR), dry matter in different organs, biomass partitioning and root:shoot ratio were
evaluated. No differences were detected between treatments for Ψpdw after 30 days; however, at midday, control plants and those under
75% FC underwent a greater reduction in Ψmdw than plants cultivated with 50% and 25% FC. After 90 days, only the plants under 50%
FC exhibited a reduction in Ψmdw. RWC was reduced at midday, but there were no differences between treatments. Nearly all growth
parameters were reduced due to water deficit, especially in the plants with 25% FC, as determined by the number of leaves, stem
diameter, plant height, LA, SLA and dry mass in several organs. LAR and root:shoot ratio were not affected. Mulungu seedlings seem
to have developed rusticity to overcome intermittent droughts with no change in the pattern of dry matter distribution. The maintenance
of turgor pressure seems to be more associated to a reduction in the growth ratio than a reduction in leaf water potential.