GERMINATION TEST IN SEEDS OF MELOTHRIA CAMPESTRIS (NAUDIN) H. SCHAEF. & S.S. RENNER

ABSTRACT The Cerrado occupies 25% of the Brazilian territory and is the second largest biome in South America, second only to the Amazon Rainforest. Hence, studies on the native species of the Cerrado are important for implementing conservation strategies. In this context, knowledge of the requirements and conditions for germination of seeds of these native species is essential. The Cerrado watermelon (Melothria campestris (Naudin) H. Schaef. & S.S. Renner) is a plant that is not cultivated, but has been used in revegetation projects in the countryside of the Cerrado because its fruits are fed upon by fauna in times of food shortage. The purpose of this study was to determine the most appropriate methodology for the germination of the Cerrado watermelon, by identifying the best-suited substrate, the optimal temperature, and the corresponding time taken for germination. The treatments consisted of four substrates: in a paper roll, on paper, in sand, and on sand; and four temperatures: 20, 25, and 30 °C (maintained constant), and a fourth temperature treatment that alternated 20-30 °C. The effect of the substrates and temperatures on seed performance was evaluated using the germination test, speed index, and average time for germination. The experimental design was fully randomized, with treatments distributed in a 4 × 4 (substrates × temperatures) factorial scheme, with four replications. Our results show that the temperature of 20 °C had a negative influence on germination in all substrates. Further, we found that the germination of the Cerrado watermelon seeds was best in a paper roll or on sand substrate, maintained at a constant temperature of 30 °C, or when temperature was alternated 20-30 °C, and the time required for germination stabilization was 30 days.

摘要 塞拉多（Cerrado）占巴西领土面积的25%，是南美洲仅次于亚马孙雨林的第二大生物群系。因此，针对塞拉多本土物种的研究对于制定保护策略具有重要意义。在此背景下，了解这些本土物种种子萌发的需求与条件至关重要。塞拉多西瓜（Melothria campestris (Naudin) H. Schaef. & S.S. Renner）是一种未被人工栽培的植物，但因在食物匮乏时期其果实会被动物取食，已被用于塞拉多乡村地区的植被恢复项目。本研究旨在通过筛选最适宜的基质、最优温度及对应的萌发时长，确定塞拉多西瓜种子萌发的最佳方法。本试验设置4种基质处理：纸卷法、纸上培养、沙中培养、沙面培养；以及4种温度处理：20℃、25℃、30℃（恒温），以及20-30℃变温处理。通过发芽试验、发芽速率指数及平均萌发时间，评估基质与温度对种子萌发表现的影响。本试验采用完全随机设计，以4×4（基质×温度）因子试验方案设置处理，共设4次重复。研究结果表明，20℃恒温对所有基质下的种子萌发均产生了负面影响。此外，本研究发现，当采用纸卷法或沙面基质、设置30℃恒温或20-30℃变温处理时，塞拉多西瓜种子的萌发效果最佳，且种子萌发达到稳定所需时长为30天。