Ploidy does not affect responses to increased soil nutrients and salinity in a perennial geophyte

Abstract

PREMISE OF RESEARCH : Polyploidy can alter plant phenotypes and may enhance the ability of plants to take advantage of high soil nutrient concentrations in their environment or exhibit tolerance to saline conditions. Experimental studies are useful to test how polyploid and diploid plants differ in their growth and reproductive success in different soil nutrient and saline conditions. METHODOLOGY : Here, we used growth chambers and reciprocal transplants in field habitats to test whether different soil nutrient–supplemented (nitrogen [N] and phosphorus [P]) and saline (NaCl) conditions and natural field soil conditions affected the number of leaves and flowers, size of longest leaves, relative growth rate, reproductive output, and survival of diploid and tetraploid individuals of Rhodohypoxis baurii var. platypetala. PIVOTAL RESULTS : Tetraploidy was not associated with an increase in the number of leaves and flowers, size of longest leaves, and relative growth rate and increased reproductive output under N or P enrichment in growth chambers and did not increase survival rate under NaCl. Reciprocal transplants showed a similar survivorship and reproductive output between diploid and tetraploid individuals, suggesting that the different ploidies are capable of establishing in each other’s environment. CONCLUSIONS : Together, findings from this study indicate that polyploidy in R. baurii var. platypetala does not necessarily confer a growth or reproductive advantage or limitation under different soil nutrient levels in the growth chambers or in the field.