Cytological investigations in poly-gamo-dioecious tree Simarouba glauca DC

摘要

In angiosperms sexual dimorphism is proved to be an evolutionary advancement and plays a major role in crop improvement in general and in tree species in particular. Identification of sex in absence of morphological markers is a difficult task in such plants. Sex determination in all dioecious plants does not follow a common mechanism. In present investigation an attempt is made to understand the mechanism of sex determination in poly-gamo-dioecious tree species Simarouba glauca DC., an important oil yielding and medicinal plant. Scoring of morphological characters in male and female S. glauca reveals that both are morphologically identical with 2n = 30 chromosomes and exhibit symmetric karyotype and with homomorphic median chromosomes with one pair of SAT chromosomes, but female plant possess chromosomes which are longer than male counterpart and the largest chromosome is more than two fold longer than the smallest.