Pollen Count Dynamics in Rapeseed Stamens in Early Spring

Pollen contains vegetative and generative cells that influence the seed set. Accurate pollen assessments help understand the breeding biology of oilseed rape. In order to evaluate the number of pollen grains in a large number of samples, an effective method should be designed. A new method was established to evaluate the pollen counts of five oilseed rape cultivars. This method mainly relies on 5% sucrose + 0.1% agar solution to suspend the pollen and uses a standard curve corresponding to the absorbance and the number of pollen grains to estimate the number of pollen grains. The linear fit formula of this standard curve was precision, and the R² value between the pollen count and absorbance reached 0.998. Furthermore, the variation in the pollen counts at three flowering stages and on two kinds of stamens was assessed. The pollen count per flower varied significantly among oilseed rape cultivars and flowering stages (GLM: p<0.001). Moreover, the number of pollen grains on long-stamen anthers was significantly higher than that on short-stamen anthers (GLM: p<0.001). In conclusion, we established a rapid, accurate method for quantifying pollen grains based on absorbance determined in a liquid suspension by light spectroscopy, which is a feasible method. In addition, the number of pollen grains under different physiological conditions also provides basic data for oilseed rape breeding.