ABSTRACT
Objective To study the reproductive biology of Chinese herbal medicine Polygonatum cyrtonema Hua. Methods The flowering habit of P. cyrtonema was observed and recorded regularly. The pollen viability at different flowering periods was detected by TTC. The stigma activity at different flowering periods was measured by the benzidine-hydrogen peroxide method. The hybridization index was estimated and pollen-ovule ratio was calculated. The breeding system of P. cyrtonema was determined by six different artificial pollination treatments. Results The flower buds of P. cyrtonema appeared at April 5. They bloomed at April 10 and fruited early in May, flowering about 30–40 days. The pollen began to have viability since the anthers were not cracked, and loss viability after flowers withered. The pollen viability at the bloom day was about 73.06%±5.19%. The stigmas began to have activity before flowers opening and lost it when the flowers began to decline. The hybridization index was 4, so the breeding system of P. cyrtonema Hua was partly self-compatible and xenogamy needing pollinator according to Dafni's standard.The pollen-ovule ratio was 1799.20±445.54,therefore the breeding system of P.cyrtonema Hua was facultative xenogamy according to Cruden's standard. The results of artificial pollination experiments showed that P. cyrtonema Hua had three breeding methods,including apomixis,selfing and outcrossing.The fruit setting rate of P. cyrtonema Hua was greatly influenced by external conditions such as strong wind and rain.Generally,P.cyrtonema Hua had a low fruit-set percentage because of obvious flower and fruit dropping. The natural fruit setting rate was only 17.46%. Conclusion The coexistence of apomixes, sexual and asexual reproduction in P. cyrtonema are the survival strategy adapting to different habitat types.
ABSTRACT
Objective To study the reproductive biology of Chinese herbal medicine Polygonatum cyrtonema Hua. Methods The flowering habit of P. cyrtonema was observed and recorded regularly. The pollen viability at different flowering periods was detected by TTC. The stigma activity at different flowering periods was measured by the benzidine-hydrogen peroxide method. The hybridization index was estimated and pollen-ovule ratio was calculated. The breeding system of P. cyrtonema was determined by six different artificial pollination treatments. Results The flower buds of P. cyrtonema appeared at April 5. They bloomed at April 10 and fruited early in May, flowering about 30–40 days. The pollen began to have viability since the anthers were not cracked, and loss viability after flowers withered. The pollen viability at the bloom day was about 73.06%±5.19%. The stigmas began to have activity before flowers opening and lost it when the flowers began to decline. The hybridization index was 4, so the breeding system of P. cyrtonema Hua was partly self-compatible and xenogamy needing pollinator according to Dafni's standard.The pollen-ovule ratio was 1799.20±445.54,therefore the breeding system of P.cyrtonema Hua was facultative xenogamy according to Cruden's standard. The results of artificial pollination experiments showed that P. cyrtonema Hua had three breeding methods,including apomixis,selfing and outcrossing.The fruit setting rate of P. cyrtonema Hua was greatly influenced by external conditions such as strong wind and rain.Generally,P.cyrtonema Hua had a low fruit-set percentage because of obvious flower and fruit dropping. The natural fruit setting rate was only 17.46%. Conclusion The coexistence of apomixes, sexual and asexual reproduction in P. cyrtonema are the survival strategy adapting to different habitat types.