Acacia meanmsii (Fabaceae) reproductive biology: pollen tube viability and growth

Abstract

-The low seed production in Acacia mearnsii De Wild. populations indicates that narrow genetic variability interferes with the reproduction. The viability of polyads of A. mearnsii trees from a seed production area was evaluated through in vitro germination and the colorimeter method. A high mean germination (73%) and low mean pollen tube growth (23%) were observed in the germplasm. Only tree 30 presented 60% germinated pollen tubes. The other means were less than 50%. On the other hand, the viability observed by the colorimeter method was high (100% viable polyads in five trees), which indicated that the colorimeter technique overestimated the true viability.This study showed that the germination ability of polyads was influenced by the genotype, contributing to a limited seed formation.

Pollination biology in an endangered rocky mountain toadflax (Linaria cavanillesii)

“…Pollen from each flower was collected at three different time intervals (12 h before flower opening and 48 h and 96 h after flower opening; 10 flowers were collected per time interval) and incubated (258C, 4 h) in GK medium (3.2 mM H 3 BO 3 , 0.8 mM MgSO 4 , 1 mM KNO 3 , 1.3 mM Ca(NO 3 ) 2 , and 0.29 M sucrose) (Wilson et al 1997). Pollen grains were observed under a microscope (4006), and germinated grains were distinguished by a pollen tube measuring at least double the length of the grain diameter (Stiehl-Alves & Martins-Corder 2007). The proportion of viable pollen was determined on 500 grains per sample.…”