RESUMO
The Brazilian semiarid region stands out in terms of sour passion fruit production. Local climatic conditions (high air temperature and low rainfall), combined with its soil properties (rich in soluble salts), increase salinity effects on plants. This study was carried out in the experimental area "Macaquinhos" in Remígio-Paraíba (Brazil). The aim of this research was to evaluate the effect of mulching on grafted sour passion fruit under irrigation with moderately saline water. The experiment was conducted in split-plots in a 2 × (2 × 2) factorial scheme to evaluate the effects of the combination of irrigation water salinity of 0.5 dS m-1 (control) and 4.5 dS m-1 (main plot), passion fruit propagated by seed and grafted onto Passiflora cincinnata, with and without mulching (subplots), with four replicates and three plants per plot. The foliar Na concentration in grafted plants was 90.9% less than that of plants propagated via seeds; however, it did not affect fruit production. Plastic mulching, by reducing the absorption of toxic salts and promoting greater absorption of nutrients, contributed to greater production of sour passion fruit. Under irrigation with moderately saline water, the plastic film in the soil and seed propagation promote higher production of sour passion fruit.
RESUMO
This study aimed to evaluate the growth and physiology of Annona squamosa seedlings under increasing irrigation depths and phosphorus doses. The experiment was conducted in protected environment, evaluating five irrigation depths and four P2O5- doses, arranged in 5 x 4 factorial scheme, in randomized blocks, with four replicates and one plant per plot. Treatments were irrigation depths of 60, 80, 100, 120 and 140% of the real evapotranspiration of the seedlings ETr and phosphorus doses of 0, 350, 700 and 1050 mg dm-3 of P2O5-. Plants were evaluated at 120 days after transplanting with respect to growth, gas exchanges, leaf water potential and total dry matter accumulation. Phosphorus dose of 350 mg dm-3 promotes satisfactory dry matter accumulation for A. squamosa seedlings, especially under 100% ETr irrigation. Leaf water potential and gas exchanges of A. squamosa are affected by water stress, through both lack and excess of water. Stomatal conductance is the variable most sensitive to the lack of water, whereas photosynthesis and water use efficiency are the most sensitive to the excess of water. Irrigation depth of 100% ETr is ideal to produce A. squamosa seedlings, but the irrigation depth of 80% ETr can be used to produce these seedlings, disregarding small losses of growth
Objetivou-se avaliar o crescimento e a fisiologia de mudas de A. squamosa sob lâminas crescentes de irrigação e doses de fósforo. O experimento foi conduzido em ambiente protegido, avaliando cinco lâminas de irrigação e quatro doses P2O5, arranjados em esquema fatorial 5 x 4, em blocos casualizados, com quatro repetições e uma planta por parcela. Os tratamentos das lâminas foram 60, 80, 100, 120 e 140% da evapotranspiração real das mudas ETr e as quatro doses de fósforo 0, 350, 700 e 1050 mg dm-3 de P2O5. As plantas foram avaliadas aos 120 dias após o transplantio, quanto ao crescimento, trocas gasosas, potencial hídrico foliar e acúmulo de matéria seca total. A dose de fósforo de 350 mg dm-3 proporciona acúmulo de matéria seca satisfatório para as mudas de A. squamosa, principalmente sob irrigação com 100% da ETr. O potencial hídrico foliar e as trocas gasosas da A. squamosa são afetadas pelo estresse hídrico, tanto por falta como por excesso de água, sendo a condutância estomática a variável mais sensível a falta de água e a fotossíntese e eficiência do uso da água as mais sensíveis ao excesso de água. A lâmina de 100% da ETr é a ideal para a produção de mudas de A. squamosa, porém a lamina de 80% da ETr pode ser utilizada para a produção de mudas de A. squamosa, admitindo-se pequenas perdas no crescimento.