3.1 Clonal characteristics and spatial architectures of diploid and tetraploid
The average number of buds on each diploid rhizome was 2.120, and the variance of buds was 0.277 (Table 2, 3). For the tetraploids, the average number and the variance of buds per rhizome was 2.315 and 0.408, respectively. For the proportion of active buds to total buds, it was 0.627 for the diploid and 0.473 for the tetraploid. The ratio of dormant buds to total buds for the diploid was 0.357, while it was 0.522 for the tetraploid. The extrema values of buds per rhizome for the diploids and tetraploids were same; both the minimum value = 1 and the maximum value = 4. These results revealed that the tetraploids possessed more rhizome buds; however, the number of active buds were lower (dormant buds were higher) than that in the diploids (Table 1). In addition, one-way ANOVA analysis showed that the above indexes, such as ratio of dormant buds to total buds, the ratio of active buds to total buds, and the ratio of dormant buds to active buds, were significantly different among diploid and tetraploid of C. udensis (P<0.05) (Table 3).
The rhizome styles of the diploids and tetraploids were primarily zigzagged, C, V, and Y (Fig. 2); the ”one” style was very rare. The spatial positions between the buds of each rhizome were basically a symmetrical distribution when there were two buds, or formed 90° angles when having 3-4 buds.
The length of rhizome internode was about 1-2cm. Based on our observation, the rhizome bud usually occurred in the rhizome node, and was thought as the ramet produced by the genet. Moreover, the rhizome nodes of some individuals had a special branch architecture. The number of branches was typically from one to four, with the highest frequency of single branches. Additional branches were typically observed for older plants (Fig. 2).
Statistical analysis of the clone reproduction for C. udensis in that year revealed that the number of ramets produced by the diploid and tetraploid individuals was minimal, and the ratio of clone individuals between the diploid and the tetraploid were both relative lower (Table 3). Thus, the C. udensis clone growth pattern was the phalanx growth form (Fig. 3).