RAMOS, F. R.; http://lattes.cnpq.br/9741718866243310; RAMOS, Fabio Rodrigues.
Resumen:
This study aimed to investigate the gas exchange, growth and biomass production of faveleira
samplings fertilized with potassium and exposed to different water conditions. The
experiment was conducted in a completely randomized design, with 4 replications and two
plants per experimental unit, with treatments arranged in factorial scheme 4 x 3,
corresponding to three doses of potassium (0 (control), 97.5 and 195 mg dm-3 K) and four
levels of water (100% (control), 75% and 50% and 25% of pot capacity (cv). The plants were
kept in black plastic bags containing 5 kg of soil, for 150 days. Increase in potassium doses
promoted rise in leaf water potential, stomatal conductance, and transpiration and
photosynthetic rates. However, there was no influence of potassium fertilizer on height,
diameter, leaf area and dry matter production of plants, except in the roots. Reduction in water
levels reduced leaf water potential, the parameters stomatal, growth and dry matter production
of plants. It is recommended that the substrate moisture level of 75% of the vessel capacity in
the early growth stages of faveleira saplings. This work aimed to evaluate the physiological
behaviour of faveleira plants grown in the field, in an a area of Caatinga, during the rainy
season and early dry period. Adult plants grown in the Nupeárido Experimental Farm, at the
Federal University of Campina Grande, Patos, Paraíba, Brazil, were selected for evaluation
during the months of March and April (wet season) and May and June (dry season), in the
year 2016. We evaluated the soil moisture content, water potential (ψw), osmotic potential
(ψπ), relative water content (RWC), stomatal conductance (gs), transpiration rate (E),
photosynthetic rate (A), intercellular CO2 concentration (Ci), instantaneous water use
efficiency (A/E) and carboxylation efficiency (A/Ci). The reduction in water availability in the
soil promoted a marked decrease in soil water potential, which was more affected than the
relative water content. The opening of the stomata was affected by the decrease in soil
moisture content, reducing the stomatal conductance, transpiration rate, photosynthesis rate,
instantaneous water use efficiency and carboxylation efficiency. The photosynthesis was more
affected than transpiration by reduction in soil moisture content.