สัณฐานวิทยาและผลของอุณหภูมิต่อการเก็บรักษาละอองเกสรหม้อข้าวหม้อแกงลิง

Abstract

Nepenthes are dioeciously plants. The flowering times vary, which causes problems with the propagation of nepenthes: pollen storage is essential for pollination and breeding. Assessment of pollen germination can facilitate breeding programs. This study targeted the optimal concentration of sugar and finding staining that reveals the germination and viability of pollen, and pollen morphology was imaged by scanning electron microscope. The optimal temperature for male pollen storage was tested experimentally. The pollen were prolate-spheroidal in shape with scabrate exine sculpturing of pollen cell wall. As a highlight of this study, we found that the sculpturing-scabrate height and density per 100 μm3 of pollen exine had significant differences (p<0.01) distinguishing the species. The rank order of sculpturing-scabrate height was N. mirabilis var. mirabilis, N. thorelii and N. mirabilis var. globose (0.77, 0.60, and 0.55 μm, respectively). The average sculpturing-scabrate density gave the rank order N. thorelii, N. mirabilis var. globosa and N. mirabilis var. mirabilis (85.00, 58.16 and 43.93, respectively). The pollen of N. mirabilis var. globosa, N. mirabilis var. mirabilis and N. thorelii were tested by Aceto orcein and 2, 3, 5-Triphenyl tetrazolium chloride. The highest pollen germination of N. mirabilis var. mirabilis and N. thorelii was found on a medium supplemented with 5% sucrose, while the highest pollen germination of N. mirabilis var. globosa was on a medium supplemented with 15% sucrose. In addition, pollen viability and germination decreased with storage time. N. mirabilis var. mirabilis pollen was stored at -80°C for 15 days. N. thorelii at -20°C for 9 days, and N. mirabilis var. globose at 4°C for 15 days. The stains did not inform about success in pollen germination. In conclusion, pollen storage with cooling is necessary to address problems with fluctuations in the time of nepenthes flowering, and for success of the Nepenthes pollinating program.