z-logo
Premium
Factors limiting seed production of Taxus Brevifolia (Taxaceae) in Western Oregon
Author(s) -
DiFazio Stephen P.,
Wilson Mark V.,
Vance Nan C.
Publication year - 1998
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.2307/2446356
Subject(s) - biology , limiting , taxus , botany , mechanical engineering , engineering
Seed production of Pacific yew ( Taxus brevifolia ), an understory conifer, was studied at four sites in western Oregon over 2 yr. The effects of pollen supplementation, overstory canopy, and predator exclusion on ovule attrition were examined. Supplemental hand‐pollination of ten trees at two sites resulted in significantly increased rates of ovule development and a doubling of seed efficiency (ratio of seeds to ovules). However, seed efficiency still averaged <15% on branches receiving supplemental pollen, so pollination was not a primary factor limiting seed production. The number of developing ovules was positively associated with overstory openness, but seed production was not. Seed efficiency was negatively associated with overstory openness. Branches bagged to exclude vertebrate seed predators had higher seed production than unbagged branches at three of four sites for 2 yr. In contrast to unbagged branches, seed production on bagged branches was positively associated with overstory openness, as was the effectiveness of bagging. Therefore, both vertebrate predation and overstory were important in limiting seed production, and these factors interacted. Factors limiting seed production varied in importance among the four sites and between years, illustrating the importance of examining multiple limiting factors over several sites and years.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here