FLOWERING PHENOLOGY AND REPRODUCTIVE CHARACTERISTICS OF CYPRIPEDIUM MACRANTHOS (ORCHIDACEAE) IN CHINA AND THEIR IMPLICATION IN CONSERVATION

Abstract

The phenology and reproductive characteristics of Cypripedium macranthos were studied in China. This slipper orchid is mainly distributed outside of the diversity center of the genus Cypripedium in China and needed urgent protection. The plant favored the weakly acidic soil and the pH of soil of 7 populations in Beijing varied from 5.85-6.92. Moreover, the organic matter differed from 9.66%-22.84%, which belonged to the first grade according to the classification criterion of soil nutrient in China. The process of germination, anthesis, pollination, fructification, flower withering, plant withering and dormancy of C. macranthos were recorded. It usually opened around the first ten-days period of June and proceeded until the end of June or the beginning of July at population level. A single flower without pollinium removal or deposition lasted about 9.42±1.81 d (n=36), while the mean flowering time of those with pollinium deposition is 6.80 ±1.30 d (n=109). The period with low temperature might play an important role in development of plant and bud. C. macranthos is selfcompatible and pollinator limitation. The number of seeds was 16254±9750 per capsule in hand-self-pollination and 15638±8257 in hand-cross-pollination, which were about 2.5 times more than that (5808±2633 per capsule) in natural pollination. So hand-pollination with more pollen might increase the number of fruits and seeds. Therefore, vegetation protection, suitable temperature of selected nursery place and hand-pollination would be important strategies in conservation of C. macranthos and might contribute more or less to resume its population.