The purpose of the work was to assess the germination process and the growth of pollen tubes in rye Secale cereale L. ssp. cereale) growing in greenhouse conditions taking into account different temperature conditions and exposures to light. The rye cultivar Dankowskie Złote, was selected for the experiment and cultivar Dankowskie Nowe as a control. Microscopic analysis were carried out using fluorescent techniques staining the preparations with aniline blue. Analysis were performed after 10 min, 1 h, 2 h and 3 h from the pollination. The results indicate a negative effect of greenhouse conditions on pollen germination, pollen tube growth and the fertilization process in rye Secale cereale (L.). The optimal greenhouse conditions for plants flowering in winter time are: exposure to the artificial lighting over plants in single day-phase 16 hours long and temperatures around 25°C for day. Temperatures lower than 20°C clearly interfere with the process of pollen grain germination, the growth of pollen tubes and the fertilization process, which in turn leads to the lower fertility and yielding of plants. In the process of producing new hybrid varieties and seed production in open-pollinated plants, plastic tunnels and greenhouses are used as isolators. In case of reproduction of the single plants or lines, selecting the optimal conditions for the fertilization process is of key importance.