The influence of pre-treatment on germination of three species of Catasetum (Orchidaceae)

Abstract: Asymbiotic germination techniques are successful in species of the Catasetum genus. The diverse composition of the culture media can be critical; however, viable seeds are required for asymbiotic germination. The reliable method for viability assessment is the tetrazolium test. A decisive step in the efficiency of the tetrazolium test is the seeds preconditioning with sucrose solution, which has the potential to improve germination. Therefore, this work aimed to evaluate the seed germination of three species of the genus Catasetum in culture media, preconditioned or not with sucrose solution. Seeds of the species Catasetum osculatum, Ctsm. galeritum and Ctsm. complanatum were assessed by tetrazolium test and germinated in two different media, pretreated or not with 10% sucrose solution. The statistical analysis showed that the use of sucrose pretreatment significantly increased the germination rates of the species. We conclude that the pretreatment with 10% sucrose for 24 hours, regardless of the species and the culture medium, significantly increases the germination of Ctsm. complanatum, Ctsm. galeritum and Ctsm. osculatum seeds.

摘要：非共生萌发（asymbiotic germination）技术在瓢唇兰属（Catasetum）物种中已取得成功。培养基（culture media）的多样组成或发挥关键作用，但非共生萌发需使用具有活力的种子。当前评估种子活力的可靠方法为四唑试验（tetrazolium test），该试验效率的决定性步骤之一是采用蔗糖溶液（sucrose solution）对种子进行预处理，该预处理具备提升种子萌发率的潜力。因此，本研究旨在评估瓢唇兰属3个物种的种子在两种不同培养基上的萌发表现，以及是否经10%蔗糖溶液预处理的影响。本研究以Ctsm. osculatum、Ctsm. galeritum和Ctsm. complanatum的种子为实验材料，通过四唑试验评估其活力，并将经10%蔗糖溶液预处理与未预处理的种子分别接种于两种培养基中开展萌发实验。统计分析结果显示，蔗糖预处理可显著提升各供试物种的种子萌发率。本研究得出结论：经10%蔗糖溶液预处理24小时，无论供试物种与培养基类型如何，均可显著提升Ctsm. complanatum、Ctsm. galeritum与Ctsm. osculatum的种子萌发率。