title: Flowering phenology and wind-pollination efficacy of heterodichogamous Juglans mandshurica (Juglandaceae).
abstract: OBJECTIVE
  Heterodichogamy differs from normal dichogamy, in that it involves two mating types (protogyny and protandry) that occur at a 1 : 1 ratio in a population. Flowering phases of the two mating types are synchronized and reciprocal, which was considered to ensure between-type outcrossing. This study aims to quantify the flowering pattern and pollination efficacy in Juglans mandshurica, a wind-pollinated heterodichogamous tree.
  
  
  METHODS
  The pattern of flowering phenology was monitored within individual trees and pollen traps were used to measure air-borne pollen loads during the spring in 2003 and 2004. Pollen longevity was determined by staining technique. Also a pollen supplementation experiment was performed in 2004 to assess pollen limitation of fruit production.
  
  
  RESULTS
  There was no overlap between sexual functions within individual trees. Flowering periods of the two mating types were reciprocal and synchronous in both 2003 and 2004. Air-borne pollen loads were large, and protogynous and protandrous individuals each produced a high pollination peak, consistent with the two blooming periods. Maximum pollen longevity was about 4 h for protandrous individuals, and 3 h for protogynous individuals. Pollen supplementation did not increase fruit production in either protogynous or protandrous individuals.
  
  
  CONCLUSIONS
  Heterodichogamous flowering in Juglans mandshurica effectively avoids selfing, promotes between-type outcrossing, and leads to efficient pollination in a natural population.
authors.affiliation: Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering and Institute of Ecology, Beijing Normal University, Beijing 100875, China.
authors.forename: Wei-Ning
authors.initials: WN
authors.lastname: Bai
authors.forename: Yan-Fei
authors.initials: YF
authors.lastname: Zeng
authors.forename: Wan-Jin
authors.initials: WJ
authors.lastname: Liao
authors.forename: Da-Yong
authors.initials: DY
authors.lastname: Zhang
mesh_terms: D001947:Breeding; D035264:Flowers / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology*; D031324:Juglans / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology*; D010507:Periodicity; D011058:Pollen / Q000502:physiology; D012098:Reproduction / Q000502:physiology