Germination and vigor of Caesalpinia pulcherrima (L.) Sw. seeds under different light and temperature conditions

ABSTRACT: Caesalpinia pulcherrima is a Fabaceae family species from Central America, which has a small size and is widely used as a living fence in the urban afforestation for streets, parks, and gardens. Based on this importance, the aim of this research was to study the influence of light and temperature on the germination of C. pulcherrima seeds. The study was carried out at the Laboratory of Seed Analysis of the Center of Agricultural Sciences of the Universidade Federal da Paraíba, Areia, PB, Brazil. The experimental design was completely randomized, comprising a 3x5 (three temperatures and five light regimes) factorial scheme with four replicates containing 25 seeds each. Germination and vigor of seeds were evaluated under temperatures of 25°C and 30ºC constant and 20-30ºC alternated in different light regimes: white, green, red-distant, red, and absence of light. Variables analyzed were: germination, first germination count, germination speed index, root length, shoot length, and the ratio of dry mass of root/shoot of the seedlings. Seeds of C. pulcherrima germinate in the presence and absence of light, being a neutral photoblastic. Recommendation to test the vigor of these seeds is the temperature of 30°C in the white light regime.

摘要：洋金凤（Caesalpinia pulcherrima）为豆科（Fabaceae）植物，原产于中美洲，植株体型小巧，被广泛应用于街道、公园与花园的城市绿化中作为活体绿篱。鉴于其重要的应用价值，本研究旨在探究光照与温度对洋金凤种子萌发的影响。本试验于巴西帕拉伊巴州阿雷亚市的帕拉伊巴联邦大学（Universidade Federal da Paraíba）农业科学中心种子分析实验室开展。试验采用完全随机设计，设置3×5（3个温度梯度与5个光照处理）的析因方案，共设置4次重复，每次重复包含25粒种子。研究分别在25℃、30℃恒温以及20~30℃变温条件下，搭配白光、绿光、远红光、红光与全黑暗5种光照处理，对种子的萌发特性与活力水平进行评价。测定指标包括：发芽率、初次发芽计数、发芽速率指数、胚根长度、胚芽长度以及幼苗根冠干重比。试验结果显示，洋金凤种子在有光与无光环境下均可萌发，属于光中性种子。本研究推荐采用30℃恒温结合白光光照处理，用于该种子的活力检测。