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：在组培苗（micropropagated seedlings）生产过程中，将植株暴露于当地环境条件的关键环节被称为驯化（acclimatization）。本研究旨在评估‘BRS Conquista’香蕉品种在驯化阶段，于不同基质与有机-矿质肥料（organomineral fertilizer）用量下的生理响应。本研究采用3×5因子试验设计（基质种类×有机-矿质肥料用量），设置5次重复，每小区种植5株组培苗。所用基质分别为椰糠、松树皮以及100%天然混合商用配方基质。所用有机-矿质肥料为4-14-8型肥料，用量梯度为0、1000、2000、3000及4000 g·m⁻³。在组培苗移栽60天后，对以下指标进行测定：叶片辐射入射量（Qleaf）、细胞间隙CO₂浓度（Ci）、气孔导度（Gs）、蒸腾速率（E）、光合速率（A）、叶肉导度（Gm）、叶绿素荧光参数（F）、光下叶片最大荧光值（Fm）以及叶面积指数（LAI）。研究结果表明，松树皮基质可为驯化阶段的香蕉组培苗生长提供适宜的生理环境，同时可获得更高的叶面积数值；中等用量的有机-矿质肥料（1000~3000 g·m⁻³）可提升植株的光合速率。