The higher availability of nutrients increases the production but decreases the quality of pollen grains in Juniperus communis L.

Next to global warming, excessive deposition of nitrogen has an alarming environmental impact on forest ecology, especially within dioecious species. Resource availability affects seed quality and can affect the distribution of plant species. Lower seed productivity can also be a result of limited pollen availability or lower pollen quality. A few studies have assessed the effect of nutrient availability on the quantity and quality of pollen grains produced. Therefore, rooted shoots of dioecious, male Juniperus communis L. grown in different nutritional conditions were used to assess the impact on productivity and quality attributes of produced pollen grains (pollen volume, morphology, germination, and chemical composition). The results indicated that nutrient availability impacts pollen grain development. Male plants growing in nutrient-rich environments appear to compensate for the lower quality of produced pollen grains by producing a higher number of male cones and thus a greater quantity of pollen. In contrast, the opposite was observed in plants growing in nutrient-poor environments. The availability of nitrogen and other nutrients will probably continue to impact soils in the foreseeable future due to anthropogenic activity and can be one of the drivers that can impact the reproduction and distribution of plants.