Study On Flowering, Fructification And Viviparity Of Polygonum Viviparum L.

Polygonum viviparum L. is the viviparous plant widespread on the plateau, and also is the main fodder plant of host insect for Cordyceps sinensis (Berk.) Sacc. Study on floral organ, morphous of fruit, seed and bulbil, process of flowering, fructification and seed setting, bulbil breeding of P. viviparum by field observation, paraffin section and cultivation in laboratory is for exploring the mechanism of viviparity, screening the suitable condition for bulbil breeding, consummating the bioresearch of viviparous plant, supporting the development and forthputting of P. viviparum.1. Flower and flowering of P. viviparum(1) Types on the inflorescence of P. viviparum by the number of flowers and bulbils are all bulbils, few flowers-much bulbils and half flowers-half bulbils. Types on flowers and bulbils in the same bract are two flowers, one bulbil and one flower-one bulbil. Types on simple flower by the color of perianth are red flowers, light red flowers and white flowers.(2) The flower season of P. viviparum is from the end of May to the end of August. Two types of flowers on single inilorescence bloom in tandem, time interval 17 days. Flowering time of the first stage flower is 51～73 days. Flowering time of the second stage flower is 60～79 days. The average value of pollen vitality are 69.57% and 43.73% to the first stage flower and the second stage flower.Two types flowers both have stigma receptivity.2. Fructification and seed setting of P. viviparumThe cypsela of P. viviparum develop from three-carpel ovary. The shape and structure of the fruits on two stage flowers arc the same. The rate of seed setting are 43% and 29% to the first stage and the second stage flower. Seed setting rate is relatively low.3. Bulbil and viviparity of P. viviparum(1) Types on bulbil by color and size are big purple red bulbils,small purple red bulbils and green bulbils.(2) The bulbil development season of P. viviparum is from the end of May to the end of August. Development time of bulbils on single inflorescence last 58～72 days. Development time of single bulbil last 41～53 days. Abscission time of bulbils is from July to August.(3) In the whole wild colonia of P. viviparum,the number of bulbils is larger than number of flowers. The length of bulbil section is 1/2～3/4 of the whole inflorescence, 9/10 at most. The number of bulbils on single inflorescence is 39~93, 64 on average. 1000-seed weight is 24.11g.(4) Viviparity of P. viviparum is vegetive organ viviparity. Bulbil is the vegetative organ of P. viviparum. Flowers and bulbils in one inflorescence develop at equal pace. Bulbils emerge by cell division and cell differentiation on bulbil primordium between two bracts. Root primordium has emerged in bulbil where adjoin bud and some of the bulbils has germinated before bulbil break away from precursor. Viviparity of P. viviparum is proved.(5) Bulbil do not have dormancy. Germination rate of the bulbils without treat is above 85%. Ascendancy on the bulbils' number and germination rate raise the chance of P. viviparum becoming a new one.The effect on germination rate by bulbil diameter is more significant than the effect by its growing site. The germination vigor, germination rate and VI of bulbils diameter in 2～3cm is highest. Its energy for germination and growth is the biggest. The effect by planting depth and matrix both are important condition for bulbil germination. Humus is profit for bulbil germination and growth. Sowing bulbils on the surface of matrix is better when breeding P. viviparum. The effect by temperature and light both are important condition for bulbil VI. Temperature effect bulbil germination greatly. The optimal temperature for bulbil germination and growth is 20℃.VI is hightest under lighting 24h. Light promote the roots, stems and leaives growing. GA3 and IAA is not profit for bulbil germination. Germination vigor and VI of bulbils effected by 100mg/L GA3 and 100mg/L IAA boost significantly. Germination vigor and VI of bulbils effected by 100mg/L IAA is higher.