Number of Pollinators and Its Visitation Rate Incur Different Intensities of Pollen Limitation in Meconopsis integrifolia

Abstract

Pollen limitation commonly exists in the alpine species, yet, experimental estimates on the changeable trajectory of pollen limitation along elevational changes are rarely. We used field observations and supplemental hand pollination treatment to estimate the variation in pollen limitation among five different altitudes populations (from 3600 m.a.s.l. to 4400 m.a.s.l.) in Meconopsis integrifolia in two consecutive years. Correlation analysis was used to estimate which factor incurred the pollen limitation. Hand supplemental pollination indicated that pollen limitation occurred in the studied populations in both years. Pollen limitation was similar among low-elevation populations but doubled in the highest elevation population (4452 m.a.s.l.). The number of pollinators and visitation rate of pollinators were negatively related to the pollen limitation. Our results indicated that number of pollinators and visitation rate of pollinators were the main factors which incurred variation in pollen limitation of M. integrifolia among different altitudes.