Morpho-physiological characterization of germination in Senna siamea

ABSTRACT Establishing the appropriate procedures for conducting germination tests in forest species is important for marketing the seeds, especially species that are not yet included in the relevant Normative Instructions. The aim of this study was to determine the ideal conditions of temperature and substrate to carry out the germination test on seeds of Senna siamea, as well as: (i) to characterise the morpho-physiology of seedling establishment, (ii) the period for seedling evaluation, and (iii) validate the efficiency of the methodology in 10 batches of seeds. The experimental design was completely randomised in a 2 x 2 factorial scheme (temperatures x substrates), with 12 replications of 50 seeds in each treatment. To evaluate the different batches, the data were submitted to analysis of variance, and the mean values compared by the Scott-Knott test at 5% probability. The percentage and speed of germination, first count, seedling length, accumulated germination, and seedling morphology were evaluated. The germination potential of S. siamea seeds is greater on paper-roll substrate at temperatures of 25 °C and 30 °C (86% and 87%). The first germination count and final seedling evaluation should be carried out 15 and 21 days after sowing, respectively. The species has epigeal germination and the seedlings are phanerocotyledonous. It was found that the method for carrying out and evaluating the germination test recommended in this study is suitable for evaluating batches of S. siamea seeds.摘要 建立林木物种发芽试验的规范操作流程，对种子商业化推广具有重要价值，对于尚未被纳入相关规范性指令的物种而言尤为关键。本研究旨在明确铁刀木（Senna siamea）种子发芽试验的最优温度与基质条件，同时实现三大目标：(i) 表征幼苗建成的形态生理学特性，(ii) 确定幼苗评估的适宜周期，以及(iii) 在10批种子中验证该试验方法的有效性。本实验采用2×2因子设计（温度×基质）的完全随机化方案，每个处理设置12次重复，每次重复包含50粒种子。针对不同批次种子的评估数据，本研究采用方差分析进行统计检验，并通过斯科特-诺特检验（Scott-Knott test）在5%显著性水平下对各组均值进行多重比较。本研究测定的指标涵盖发芽率、发芽速率、初次发芽计数、幼苗长度、累计发芽率以及幼苗形态特征。铁刀木种子在纸卷基质、25℃与30℃条件下的发芽潜力最优，发芽率分别可达86%与87%。初次发芽计数与最终幼苗评估应分别于播种后15天与21天完成。该物种具备出土萌发（epigeal germination）特性，其幼苗为显子叶型（phanerocotyledonous）。研究结果表明，本研究推荐的铁刀木种子发芽试验实施与评估方法，可有效用于该物种种子批次的品质评价。