Photochemical efficiency in cladodes of ‘Gigante’ cactus pear cultivated under different spacings and organic fertilization

ABSTRACT The objective of this study was to determine the photochemical efficiency of ‘Gigante’ cactus pear cultivated under different spacings and bovine manure doses in the semi-arid region. The experiment was conducted in a randomized block design in a 4 x 3 x 7 factorial scheme, with three replicates. The first factor consisted of four doses of organic fertilization (0, 30, 60 and 90 Mg ha-1 year-1 of bovine manure), the second one, of three spacings (1.0 x 0.5, 2.0 x 0.25 and 3.0 x 1.0 x 0.25 m) and the third one of seven reading times (6, 8, 10, 12, 14, 16 and 18 h). Chlorophyll a fluorescence readings were taken in cactus pear cladodes in the dry and rainy seasons using a pulse-modulated fluorometer. Cladodes of ‘Gigante’ cactus pear cultivated under different spacings and bovine manure doses undergo changes in photosystem II during the dry season under the physiographic conditions of the semi-arid region in Bahia. During the rainy season in the semi-arid region, the photosynthetic yield in cactus pear cladodes is considered ideal.

摘要 本研究旨在探究半干旱地区不同种植间距与牛粪施用量下栽培的‘巨人’梨果仙人掌的光化学效率。本试验采用随机区组设计（randomized block design），设置4×3×7三因素析因试验方案，共3次重复。第一个因素为4个有机肥施用量梯度：0、30、60、90 Mg·ha⁻¹·a⁻¹ 牛粪；第二个因素为3种种植间距：1.0×0.5、2.0×0.25、3.0×1.0×0.25 m；第三个因素为7个测定时间点：6、8、10、12、14、16、18 h。本研究使用脉冲调制式荧光仪（pulse-modulated fluorometer），分别在旱季与雨季测定梨果仙人掌肉质茎的叶绿素a荧光（Chlorophyll a fluorescence）参数。在巴伊亚州半干旱地区的自然地理条件下，不同种植间距与牛粪施用量下栽培的‘巨人’梨果仙人掌肉质茎的光系统Ⅱ（Photosystem II）在旱季会发生变化。在半干旱地区的雨季，梨果仙人掌肉质茎的光合产率处于理想水平。