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第五届全国苏铁学术会议

作者： Xin Wang~1 Nan Li~2 Jinzhong Cui~3 1 State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,39 Beijing Dong Road,Nanjing 210008,PR China 2 Shenzhen Fairy Lake Botanical Garden,Shenzhen 518004,China 3 Insitute of Botany,20 Nanxincun,Xiangshan,Beijing 100093,China

Cycads used to be a dominant plant group during the *** fossils of cycads or their allies have been documented,but most of them are *** organs are scarce and mostly found detached from vegetative *** cycad reproductive parts,ovulate cones are rather frequently seen in the fossil record,while pollen cones are *** we report a cycadalean pollen cone connected with its vegetative parts from the lower Jurassic of Inner Mongolia,*** pollen cone is situated on the terminal of the stem and in the center of the leaf *** pinnate leaves have lateral leaflets attached decurrently and almost perpendicularly to the *** have parallel venation with rare interconnection,and are hypostomatic bearing haplocheilic stomata with a volcano-crater-like *** epidermal cells of the leaflets are elongate on the adaxial surface and almost isodiametric on the abaxial surface,with straight cell *** elongate oval cone has a slender stalk,with microsporophylls helically arranged around the cone *** situ pollen grain from the microsporophyll is oval and *** these characters demonstrate a strong affinity to the extant *** is the first record of cycadalean pollen cone with in situ pollen grain and organically connected with its vegetative parts,and therefore sheds new light on the general morphology and evolution of cycad plants.

关键词： Jurastrobus cycad pollen cone foliage Inner Mongolia environmental change Jurassic

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Temporal and spatial variation of pollen yield in natural populations of Pinus roxburghii

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Forestry Studies in China 2012年第1期14卷 20-29页

作者： Vinod Prasad KHANDURI Department of Forestry Mizoram UniversityTanhrilAizawl 796001India

Male components of the reproduction process in Pinus roxburghii were investigated for their variation in time and space as well as pollination, viz. flowering phenology, pollen production variability and pollen dispersal, for five successive years at two different locations （at the lower and higher elevations）. The study reveals that elevation and the hour of the day are the main determi- nants of anthesis and microsporangium dehiscence, because both are related to temperature and humidity. The receptivity of ovulate cone strobili or female strobili occurred earlier at the lower elevation than at the higher elevation, with a longer receptivity period in the latter case. The phenology of male and female cones varied significantly between years and elevations. The determinations of pol- len yield considered various sources of variability, i.e., the number of pollen strobili per branch, strobili per tree, microsporangia per tree and pollen grains per tree. Each of these parameters revealed significant year-to-year and elevation effects. Year-to-year varia- tion in the production of pollen cone and pollen grains with mass production after a three-year period revealed a three-year cycle of masting in pollen production in P. roxburghii. The pollen dispersal decreased quickly with distance from the pollen source. As a con- sequence, a distance of 600 m was proposed as a minimum to prevent contamination by pollen in the management of seed orchards. The results ultimately suggest that the ample production of pollen grains per tree along with flowering synchrony and long dispersal of pollen grains results in homogeneity in large populations.

关键词： chir pine pollen cone gene flow elevation Himalayas

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Male cone Evolution in Conifers:Not All That Simple

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American Journal of Plant Sciences 2014年第18期5卷 2842-2857页

作者： Christian Schulz Kristina Vanessa Klaus Patrick Knopf Marcus Mundry Veit Dorken Thomas Stutzel Evolution and Biodiversity of Plants Ruhr-Universitat BochumBochumGermany Botanischer Garten Rombergpark DortmundGermany Heisenberg Gymnasium DortmundGermany Fachbereich Biologie M 613 Universitat KonstanzKonstanzGermany

Despite the simple structure of male conifer cones, there is an enormous variability in cone properties observed upon more careful examination. The diversity ranges from simple cones to compound cones. Moreover, cones can be distinguished according to different spatial distributions on the tree. Simple cones are distributed either as solitary cones or as fascicular or clustered aggregations, while compound cones only exhibit fascicular or clustered aggregations. Here, we demonstrate that these different spatial distribution patterns correlate with distinct leaf types and variable branching frequencies. Furthermore, we provide new insights into the evolution of the sporangiophore, particularly in Taxaceae. Two notably important and fast-evolving characters of conifers are the number of sporangia per sporangiophore and the number of sporangiophores per cone. We demonstrate, across many species and types of cones, how these characters are able to adjust according to the optimal amount of pollen.

关键词： pollen cone Phylogeny Gymnosperms Compound cone Microsporophyll

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