OBSERVATIONS ON THE CHROMOSOME NUMBERS OF 4 SPECIES IN ACTINIDIA

1. In this paper, the somatic chromosome numbers of 4 species in Aetinidia are counted as follows: A. arguta (Sieb. et Zuce.) Planchex Mig. 2n=116,A. chinensis Planch var. chinensis 2n=58, A. eriantha Benth. 2n=58, A. valvata Dunn 2n=116. Of the four species, the chromosome number of A. valvata Dunn is recorded for the first time.2. The basic chromosome number, the sex chromosomes, the chromosome ploidy variation on intraspecies and interspecies and the effects of latitudes and actitudes on the distribution of diploids and polyploids in Actinidia have been discussed.(1). Such chromosome numbers as 2n=58, 2n=116 and 2n=174 reported by us and other authors suggested that the basic chromosome number for this genus be 29.(2). Thepolyploid series with 2n=58, 116 and 174 mentioned above is unlikely to suggest that there should be a simple sex chromosome in the chromosome set of Actinidia.(3). The chromosome numbers in Section Leiocarpae are largely 2n=116 (4x), and in Section Stellatae are 2n=58 (2x) except A.chinensis Planch var. hispida (or A. deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson). These results seem to indicate that the classification derived from morohology observation is coincided with the data of chromosome numbers at the level of intersection. It is obvious that further chromosome number reports in this genus are necessary to verify this hypothesis. (4). The species of Sect. Leiocarpae involved in this paper, which is a group of temperate model possessing the character of the flora of Eastern Asia, are largely polyploid, while the two species, A. chinensis Planch var.chinensis and A.eriantha Benth., in Sect. Stellatae which is a group of subtropic model connected with the flora of Southeastern Asia are diploid. In Sect.Stellatae, the diploid variety A. chinensis Planch var. chinensis distributed in the tower latitude area including Henan, Anhui, Jiangsu, Zhejang, Jangxi,Fujian and Guangdong, where as the hexaploid variety A.chinensis Planch var. hispida (or A. deliciosa), sharing the common latitudes with the former, distributed in the western area with higher altitude largely including Sichuan,Guizhou and Yunnan. Therefore, it is obvious that the polyploids in this genus adapted to higher latitude and higher altitude habitats. According to the statement that polyploids are derived from diploids, somepolyploid species in Sect. Leiocarpae might be advanced species whose ancestry had inhabited the distribution centre of Actinidia.