Effects of saline water and potassium fertilization on photosynthetic pigments, growth and production of West Indian Cherry

Abstract Due to the scarcity of water in the semi-arid region of Northeast Brazil, in both quantitative and qualitative terms, the use of saline water in agriculture should be considered as one alternative for irrigated agriculture. This study therefore aimed to evaluate the photosynthetic pigments, growth and production of West Indian Cherry as a function of irrigation using waters with different salinity levels and potassium (K) fertilization, after grafting. The study was carried out in drainage lysimeters under greenhouse conditions, in a eutrophic Regolithic Neosol with sandy loam texture, in the municipality of Campina Grande, PB. The experiment was set in a randomized block design, to test two levels of irrigation water electrical conductivity - ECw (0.8 and 3.8 dS m-1) and four K2O doses - KD (50, 75, 100 and 125% of recommendation), with three replicates. The dose relative to 100% corresponded to 79.2 mg K2O kg-1 of soil. Irrigation with high salinity water stimulated the biosynthesis of chlorophyll b and carotenoids, while the chlorophyll a content and the growth of the cherry were reduced markedly in the post-grafting phase. The harmful effects of salinity on the total number of fruit and fresh mass of West Indian Cherry fruit were minimized with potassium fertilization.

摘要 鉴于巴西东北部半干旱地区水资源在数量与质量层面均存在匮乏问题，将咸水应用于农业生产可作为灌溉农业的备选方案之一。为此，本研究旨在评估嫁接后的西印度樱桃（West Indian Cherry）在不同盐度灌溉水与钾肥（K）配施条件下，其光合色素、生长态势与果实产量的响应规律。本试验于巴西帕拉伊巴州坎帕格兰德市的温室环境下开展，供试土壤为质地砂壤土的富营养岩性新成土（Regolithic Neosol），采用排水蒸渗仪（drainage lysimeters）进行试验。试验采用随机区组设计，设置2个灌溉水电导率（electrical conductivity of irrigation water, ECw）水平（0.8与3.8 dS·m⁻¹）以及4个氧化钾（K₂O）施用量梯度（KD：分别为推荐施用量的50%、75%、100%与125%），每组处理设置3次重复，其中100%推荐施用量对应每千克土壤施用79.2 mg K₂O。研究结果表明，高盐度灌溉水可促进叶绿素b与类胡萝卜素的生物合成，但嫁接后阶段的叶绿素a含量与西印度樱桃的生长态势会受到显著抑制；而施加钾肥可有效缓解盐胁迫对西印度樱桃单株结果总数与果实鲜质量造成的不利影响。