Effects of some environmental and chemical factors on germination and pollen tube growth in petunia hybrida

Pollen germination and pollen tube growth are essential processes that ensure the reproduction of flowering plants. Pollen grains need a suitable culture medium for germination and growth that in natural condition is prepared by stigma surface. Essential factors for this phenomenon including Ca, B, K, and sucrose. Additional factors such as growth regulators, flavonoids and environmental conditions are affective on the pollen germination and pollen tube growth (Usually experimental tests on the growth media of pollen perform as in Vitro, because pollen tube growth is rapid in this condition). Alternatively the possibility of different studies on preparation of cultures media as well as the study of the effect of some factors on pollen germination and pollen tube growth are provided. In this study, different culture media prepared and the effects of factors such as pollen age, different ions, quercetin, variable sucrose concentrations, cold and on pollen germination and and pollen tube growth in petunia hybrida. were investigated. The pollen grains collected from opening buds at 8-9 AM showed the highest rate of pollen germination and pollen tube growth. The growth basic medium containing 0.02 g calcium nitrate [Ca(NO3)2], 0.05 g boric acid (H3BO3), 0.02 g potassium nitrate and 0.4 g agar in 100 mL of distilled water was a suitable medium but this medium needed the other essential factors such as follows: sucrose that its optimum concentration was 15%. Cold treatment was the most important factor so that in the pollen grains pretreated with cold for 24 h at 10°C, pollen germination increased significantly compared to unexposed to cold ones (over 90% comparison to 10-20%). The pollen tubes of those witch were pretreated with cold showed a usual and regulated growth. In addition, the rate of growth was higher. The pollen tubes of control samples were bulbed and disrupted and most pollen cytosolic materials released out. Quercetin increased the rate of growth but this increasing was not significant.