Abstract:

In order to further research on sexual hybridization and seed orchard breeding in Pinus tabulaeformis Carr., in vitro germination and characteristics of germination on pollen of P. tabulaeformis were studied. The results showed that in medium without sucrose, the pollen still had capability to germinate, although the germination rate was relatively low. The sucrose could promote pollen germination significantly, but high concentration of sucrose inhibited pollen tube growth. Tube branches could be formed during germination, and the frequency of branched pollen grains was positively correlated with sucrose concentration. At early of germination, boron acid was able to accelerate the pollen germination. However, excessively high concentration of the boron acid inhibited germination. A relatively high germination rate could be observed in all treatments with different concentrations of Ca2+. Temperature promoted pollen germination, but the rate of germination decreased with temperature increase after 26℃. Integrating pollen germination rate, tube growth and frequency of branched pollen, the components of optimal liquid medium for P. tabulaeformis should be 2.00% sucrose+0.075% boron acid+0.005% Ca2+. The germination rate could be reached (96.10±0.47)% after 72 h cultured at 26℃.