Development of groups of male strobili,anthesis and microsporangium dehiscence in Pinus roxburghii

The development of groups of male strobili and effect of temperature and relative humidity on anthesis and microsporangium dehiscence were analysed in Pinus roxburghii at two different altitudes. The study has revealed that the groups of male strobili took over one month for full maturation, whereas the anthesis cycle was completed within two days at lower altitude and after four and a half days at higher altitude. The peak period of anthesis (PPA) and microsporangium dehiscence were between 1200 hr to 1400 hr at both the altitudes. Under experimental conditions, inside a climatic chamber the anthesis and microsporangium dehiscence oscillated sharply by different levels of temperature and relative humidity. A temperature range of 25 C to 28 C was optimal for anthesis, while presence and absence of light did not have any effect on this process.