Physiological analysis of micropropagated banana ‘BRS Conquista’ seedlings acclimatized under different substrates and organomineral fertilizer doses

Abstract In the production of micropropagated seedlings, an important step is the exposure of plants to local environmental conditions, called acclimatization. Thus, the aim of this study was to evaluate the physiological response of banana ‘BRS Conquista’ cultivar, under different substrates and organomineral fertilizer doses during acclimatization. The experimental design used was a 3 x 5 factorial scheme (substrates x organomineral fertilizer doses), with five replicates and five seedlings per plot. The substrates used were: coconut fiber, pine bark and 100% natural mixed commercial formula. The organomineral fertilizer used was 4-14-8 at doses of 0, 1,000, 2,000, 3,000 and 4,000 g m-3. At 60 days after seedlings transplant, evaluations were performed regarding radiation incidence (Qleaf), internal CO2 concentration (Ci), stomatal conductance (Gs), transpiration rate (E), photosynthesis (A), mesophyll conductance (Gm), chlorophyll fluorescence (F), maximum leaf fluorescence in light (Fm) and leaf area index (LAI). It was observed that the pine bark substrate provided adequate physiological levels for the development of banana seedlings during acclimatization, as well as higher leaf area values. Intermediate organomineral fertilizer doses (1,000 to 3,000 g m-3) resulted in higher photosynthetic rates.

摘要：在微繁殖幼苗的生产中，将植株暴露于当地环境条件的重要步骤被称为驯化。本研究旨在评估香蕉品种‘BRS Conquista’在驯化阶段于不同基质与有机-矿质肥料施用量下的生理响应。本试验采用3×5因子试验设计（基质×有机-矿质肥料施用量），设置5次重复，每小区种植5株幼苗。供试基质包括椰糠、松树皮以及100%天然混合商品基质；供试有机-矿质肥料为4-14-8型，施用量分别为0、1000、2000、3000、4000 g·m⁻³。于幼苗移栽后60天，对叶片辐射入射量（Qleaf）、叶片内部CO₂浓度（Ci）、气孔导度（Gs）、蒸腾速率（E）、光合速率（A）、叶肉导度（Gm）、叶绿素荧光（F）、光下最大叶片荧光（Fm）以及叶面积指数（LAI）开展测定。结果表明，松树皮基质可为驯化阶段的香蕉幼苗生长提供适宜的生理水平，同时可获得更高的叶面积值；中等施用量的有机-矿质肥料（1000~3000 g·m⁻³）可提升幼苗的光合速率。