• Title/Summary/Keyword: Dispersal mechanism

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Changes of Land-Use Policy in Rural China (1980년대 후반 이후 중국 농촌 토지제도의 변화)

  • Moon, Soon-Cheol
    • Journal of the Korean Geographical Society
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    • v.31 no.3
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    • pp.558-576
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    • 1996
  • Since 1978. China has progressed her reforms of her economy. In this process, refroms in rual area have been operated with top priority. The system of collective economy had been changed into that of private economy. Rural farming and land-use system had been changed also. The household responsibility system took the place of a People's Commune. That was the system that could inspire farm-household with a will to work, and hence, increase the productivity of agriculture. However, with the developement of market mechanism in the later 1980s, that system got inadequate to new situation. For instance, incentives of a will to work slowly decreased, agricultural productivity did not increase, and labor forces were tremendously transferred to non-agricultural sector. This situation created the demand for a new system of rural land policy and use. This paper intends to describe changes of new system of land use in rual China. Those changes are as follows. 1. The system of land-circulation has been spread widely. 2. 'Liangtianzhi' (the system of two kind land-use) divided the land into two kinds, 'kouliangtian' (the land of food) and 'zerentian' (the land of obligation). The one is allocated in proportion to the per capita, and to support farm-household' and function, the other is allocated in proportion to the labor force, in order to increase the commercial function of land. 4. 'Guimojingying' (management of scale): For overcomint the disadvantage of dispersal of land, the relative concentration of land was required. 4. 'Gufenzhi' (a joint-stock system) is practised for the purpose of establishing clear-cut lines of land ownership. 5. 'Sihuangpaimai' (auction the use right of four kinds of wasteland) is for full-using of the wasteland. It can be apprehended that these systems and policies were the process of adaption to market mechanism. In these, rural China could escape form the disorder due to rapid changes, and overcome the existing contradiction.

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Flowering, Fruiting, Seed Fall and Seed Viability of Acer pseudosieboldianum in Mt. Jungwang, Gangwondo (강원도 중왕산 당단풍나무의 개화, 결실, 종자 낙하량 및 종자활력)

  • Kim, Hoi Jin;Kim, Gab Tae
    • Journal of Korean Society of Forest Science
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    • v.105 no.1
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    • pp.42-47
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    • 2016
  • To examine the natural regeneration in the natural mixed-broadleaved forest, flowering, fruiting, seed-fall, and seed viabilities of Acer pseudosieboldianum (Ap) were investigated in Mt. Jungwang, Gangwon-do, from 2009 to 2015. The flower of Ap consisted many male and bisexual flowers on the corymb. Flowering dates are differed between sex morph in the same inflorescence. Stamens are stop growing and disappeared after pollinated pistil begin to grow in bisexual flowers, and male flowers have vestial pistil. The flowers of Ap might be pollinated by Apis mellifera, Andrenidae spp. and Syrphinae spp. Ap had some mechanism to prevent from self pollination with heterodichogamy. Mean annual seedfall of Ap was 70,780 ea/ha (ranged 310~234,840 ea/ha). Annual seedfall of Ap varied severely, and the maximum was about 760 times the minimum. Annual seed production of Ap might be to a normal distribution. Rates of damaged or decayed seeds are highest 59.3%, and those of sound seeds are 23.9%, Those of undeveloped and empty seeds are 9.2% and 7.6%, respectively. The most important factors influencing sound seed production might be the density and activities of insect pollinators and sucking pest in the flowerwing period, middle-late May. Successful regeneration of Ap might be in masting year and on the gap sites with proper conditions to germinate and grow. To understand the natural regeneration of deciduous hardwoods, further study on the characteristics of flowering and fruiting, pre- and post-dispersal seed predation, and annual variation on these factor should be needed.

Flowering, Fruiting, Seed Fall and Seed Viability of Acer ukurunduense in Mt. Jungwang, Gangwondo (강원도 중왕산 지역에서 부게꽃나무의 개화, 결실, 종자낙하량 및 종자활력)

  • Kim, Gab Tae;Kim, Hoi Jin
    • Journal of Korean Society of Forest Science
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    • v.103 no.2
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    • pp.153-158
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    • 2014
  • To examine the natural regeneration in the natural mixed-broadlived forest, flowering, fruiting, seed-fall, and seed viabilities of Acer ukurunduense Trautv. & C.A. Mey. (AU) were investigated in Mt. Jungwang, Gangwon-do, from 2009 to 2013. The flower of AU consisited many male and bisexual flowers on the raceme (unusual panicle) and the arrangement of two sex morphs are differed for each inflorescence. Flowering dates are differed between sex morph in the same inflorescence. Stamens are stop growing and disappeared after pollinated pistil begin to grow in bisexual flowers, and male flowers have vestial pistil. The flowers of AU might be pollinated by Apis mellifera, Thyris fenestrella seoulensis, Cerambycidae sp., Andrenidae sp. and Ctenophora sp., and had some mechanism to prevent feom self pollination. The number of flower buds per inflorescence is 189 on June 8, and that of young samaras per inflorescence is 41.2 on June 21. At last ripened samaras per inflorescence is reduced 33.4 on September 5. Mean annual seedfall of AU was 6,720 ea/ha (ranged 670~17,930). Rates of sound seeds are highest 43.2%, and those of damaged or decayed seeds are 41.8%,. Those of undeveloped and empty seeds are 10.2% and 4.8%, respectively. Successful regeneration of AU might be in masting year and on the gap sites with proper conditions to germinate and grow. To understand the natural regeneration of the species, Genus Acer, further study on the fruiting habit, pre- and post-dispersal seed viability, and annual variation on these factor should be needed.

Genetic Diversity and Structure of a Rare and Endemic, Spring Ephemeral Plant Corydalis filistipes Nakai of Ullung Island in Korea (울릉도 희귀.특산 식물 섬현호색의 유전적 다양성과 구조)

  • Kim, Jin-Seok;Yang, Byeong-Hoon;Chung, Jae-Min;Lee, Byeong-Cheon;Lee, Jae-Cheon
    • Journal of Ecology and Environment
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    • v.29 no.3
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    • pp.247-252
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    • 2006
  • For the spring ephemeral and myrmecochorous perennia, Corydalis filistipes Nakai (Fumariaceae), rare and narrow endemic to Ullung Island in Korea, genetic diversity and structure of 4 subpopulations of the species were investigated with allozyme markers. Levels of genetic diversity (A=1.73, $P_{95%}$=61..2%, Ho=0.201, He=0.167) were relatively lower than those of other endemic species with widespread distribution range, but considerably higher than other endemic species with similar life history traits isolated in island. The moderate level of genetic diversity within subpopulations in C. filistipes is characteristic of the species with predominantly outcrossing, myrmecochorous seed dispersal by dual function of the elaisome and mode of sexual and asexual reproduction by the cleistogamy. The analysis of fixation indices showed an overall excess of heterozygotes (mean $F_{IS}=-0.1889,\;F_{IT}=-0.1226$) relative to H-W expectations. About 5.6% of the total genetic variation was found among subpopulations ($F_{ST}$=0.0557). The strategies of reasonable conservation and management, and the maintenance mechanism of genetic diversity of Corydalis filistipes Nakai, endemic plant species in Korea were discussed.