Interspecific Compatibility of Melastoma candidum and M. sanguineum

The cross compatibility between M. candidum and M. sanguineum, and morphological differences among offspring and their parents were investigated. Reciprocal crossings between M. candidum with M. sanguineum were conducted in 2014. Pollens from heteromorphic stamens germinated and grew into the bottom of stigma after 24 h. For M. candidum, callose appeared in the upper part of stigma, and some appeared along pollen tube wall as well, while it was not obvious in M. sanguineum. The results showed that cross-compatibility between M. sanguineum and M. candidum was high. M. candidum ♀ × M. sanguineum ♂ had 83.33% fruit set with pollens from short stamens and 93.33% with pollens from long stamens. M. sanguineum ♀ × M. candidum ♂ had 76.67% fruit set of with pollens from short stamens and 80.00% with pollens from long stamens. The pollination effect of pollens from long stamens of M. sanguineum was better than that of pollens from short ones, while there was no significant difference between the pollens from heteromorphic stamens in M. candidum. Most offsprings have 39.47% greater plant height than the average of their parents and 55.35% longer leaves. The number of leaf vein was seven, which was the same as M. candidum. Heteromorphic stamens had no significant effects on the morphology of offspring. The leaf shape of offspring from obverse cross (M. candidum ♀ × M. sanguineum ♂) was ovate-lanceolate and shoots were covered with short coarse pubescence, while that of the offspring from inverse cross (M. sanguineum ♀ × M. candidum ♂) were ellipse-lanceolate and shoots were covered with scale pubescence.