Studies on Pollination,Capsule Setting and Asymbiotic Seed Germination of Oncidium

• Main Authors: Meei-Shiou Yih, 易美秀
• Other Authors: Tsai-Yih Wang
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/98032633317994177915

碩士 === 國立中興大學 === 園藝學系 === 88 === Summary The purpose of this research was to investigate the reasons of 1ow capsule formation ratio ,and effect of capsule maturity and medium composition on seed germination in Oncidium. There were fourteen cultivars pollinated by cross (interspecific、intergeneric) or self obtain capsules ,while few cross combinations were able to formate capsules. In experiment:two cultivars could formate capsules by self pollination ,seven interspecific cross combinations could formate capsules and two intergeneric cross combinations could formate capsules. In the meantime ,many cross combinations had unilateral cross incompatibility. Flower age and pollen age affect capsule formation ratio. The earlier the flower blooming ,the easier the fruit setting. In Onc.Sharry Baby‘Sweet Fragrance’and Colm.Jungle Monarch‘Everglades’,the flower age were older than 15 days ,both would lose their fruit setting ability. In Onc.Dr.Schragen‘Nopporn’the pollen age was older than 7 days ,would lose its fruit setting ability. The growth of pollen tubes from self-incompatibility would be inhibited at stigma or style. As above , so the interspecific incompatibility would be inhibited at stigma or ovary. Incompatibility was the major reason of 1ow capsule formation ratio. The pedicles turned yellow 13 days ,while incompatible cross combinations pollinationed. Longitudinal section of cross seeds from interspecific pollination at various maturity were observed. The outer and inner integument formated at 45 days after pollination and at 60 days mature embryo sac formated. The proembryo developed at 90 days after pollination. The cells of embryos increased continuously at 120 days after pollination. The embryo divided two regions:small and large cell regions ,150 or 158 days after pollination. Seeds were not able to germinate from 60、90 days after interspecific pollination. Seeds were able to germinate at 120 days after pollination. The highest germination ratio occurred when capsules turned greenish yellow at 150 or 158 days after pollination. Germination ratio was enhanced as the seed maturity increased. The 1/4-1/2 strength MS medium was the most suitable for seed germination. The optimum medium for seeds germination was 2g/l Hyponex 1＋2g/l activated charcoal＋2g/l tryptone＋0.9% Difco-agar with 20g/l-25g/l sucrose. 2g/l Hyponex 1 medium (containing 20g/l sucrose、2g/l tryptone and 0.9% Difco-agar) with 2g/l activated charcoal and 10ml/l coconut water increased seed germination and enhanced development after germination. The 1/4 strength MS medium (containing 20g/l sucrose、2g/l activated charcoal and 0.9% Difco-agar) with 10ml/l coconut water was the most suitable medium in immature seed germination. The 1/4 strength MS medium was the most suitable for protocrom transplantation. The optimum medium for protocrom transplantation was 2g/l Hyponex 1＋2g/l tryptone＋2g/l activated charcoal＋0.9% Difco-agar with 10g/l-20g/l sucrose. In seedling with two leaves ,the optimum medium for transplantation was 2g/l Hyponex 1＋2g/l tryptone＋2g/l activated charcoal＋0.9% Difco-agar.