青藏铁路路基边坡植草技术

青藏铁路是举世瞩目的宏伟工程，保护高原生态环境，保护高原生态平衡是青藏线建设工作的重点。植草防护铁路路基边坡可以恢复因铁路建设对原有植被地的破坏。本文着重介绍青藏铁路路基边坡植草的试验及种植、养护等情况。     

野生植物种子的传播方式

世界万物的生命是丰富多彩的,自然界中每一种生命都会以他自己的方式来繁衍后代,植物要生存发展就会想尽办法来繁衍自己的后代,于是在亿万年的进化过程中,每种植物都有让自己的种子"旅行"的特殊本领,使得种子可以广为传播,生生不息。牛马有脚,飞鸟有翅,而遍布世界的植物要把生命的种子传播到大地的各个角落,靠的是什么呢?野生植物传播种子有两种方式:一是借助外力,如风力、水力、动物和人类的携带;二是依靠自身所产生的力量,主动传播。     

中国樟科植物的地理分布

 From the study of the geographical distribution of Chinese lauraceous genera and species, we may concludely obtained some results as follows:      1)  Lauraceous family is a pantropical one in distribution, sometimes it may be reached to the subtropical or temperate zone.  There are 18 genera in China natively. Among them 17 genera are of the tropical distribution-pattern.  The tropical Asia dis- tribution-pattern, i.e. Indo-malaysian distribution-pattern, is the nucleus of Chinese lauraceous flora.  Only 1 genus is of temperate distribution-pattern, i.e. the East Asia- North America distribution-pattern. From the analysis of the primitive forms and the concentration of species in these genera, we may regard that:  a)  All genera of the tropical distribution-pattern were originated at Gondwana in the past period.  South- western and Southern China may be the birth-land of some genera of tropical distribu- tion-pattern because it was the northern boundary of Gondwana in the past period. b)  The genus of temperate distribution-pattern may be originated in the montane region of Western or South-western China.       2)  Yunnan, Guangdong, Guangxi and Sichuan are the provinces having laura- ceous species in abundance. But the provinces having lauraceous endemic species in abundance are Yunnan, Guangdong, Taiwan,, Guangxi and Sichuan. In general Chinese lauraceous plants are distributed mainly in south-western and southern parts of China. The southeastern and southern parts of province Yunnan are of great abundance in lauraceous species or endemic species.  The species amount of lauraceous species in these two parts of Yunnan is 67.3% of the total species amount of the lauraceous flora in that province.  It may be explained by the fact that a) where it is of existence of primary forest, b)of great specific endemism in the rocky region and c)  the passway in migration of lauraceous plant from east to west or reverse.      3)  The great similarity of lauraceous flora  between  Yunnan  (especially  its western or north-western part) and Xizang (especially its southern or south-eastern part), as well as between Guangdong and Guangxi, may be exhibited by the background in perfect harmony of each own flora with environment in the past period.  The en- demism of lauraceous flora in Taiwan and Hainan is manifest from the standpoint of island's isolation.  But the latter is of a more manifest one, because it is situated at the southern latitude and is more adaptive to the development of lauraceous plant.       4)  The deciduous species of lauraceous plant which are the principal elements in the flora of subtropical or temperate zone, are mainly of inland distribution-pattern. Their geographical distribution are more concentrated  at  the  montane  region  of Western or South-western China.  Where it may be the birth-land of the subtropical or temperate lauraceous species, or even of the whole temperate flora.