Effect of root colonization with Piriformospora indica and phosphate availability on the growth and reproductive biology of a Cyclamen persicum cultivar

• Piriformospora indica enhanced P content and growth of Cyclamen persicum at standard P supply.
• Numbers of flowers and unfolded leaves increased, while cultivation period decreased.
• The proportion of homogeneous microspores and viable pollen and ovules was elevated.

This study examined the effects of root colonization with the symbiotic fungus Piriformospora indica on Cyclamen persicum ‘Melody’ if combined with different supplies of phosphates. The four test groups received a standard supply of phosphorus (P) with P. indica, a standard P supply without P. indica, a limited P supply with P. indica, and a limited P supply without P. indica. We examined the effects on both vegetative features (cultivation period required to obtain marketable plants, numbers of flowers and unfolded leaves, and plant diameter) and generative features (microsporogenesis and the viability of pollen and ovules). Results showed that both the supply of phosphate nutrients and P. indica have a significant impact on the development of vegetative and generative characteristics. It was also demonstrated that a standard P supply had a positive effect. In addition, the combination of a standard P supply and P. indica colonization had an even greater positive effect, with P. indica inoculation enhancing P absorption by a significant amount. The numbers of flowers and unfolded leaves and the plant diameter increased, and the growing period required to obtain marketable plants was reduced by one week. When a standard P supply was combined with P. indica inoculation, flowers developed the highest proportion of homogeneous microspores, and both pollen grains and ovules achieved maximum viability. The poorest results were obtained for the group that received little P fertilizer and no P. indica inoculation. P. indica inoculation improved pollen and ovule viability in both groups, but most significantly in the group that also received ample P. Holding the P supply even, the group without P. indica inoculation displayed lower viability. The P supply was revealed as the dominant factor. Plants that received ample P developed more viable pollen and ovules on average than did plants that were less adequately supplied.