A Chromosomal Study on 7 Species of Smilax L.

The chromosome numbers and karyotypes of 7 species of Smilax L. in Liliaceae (s. 1.) are cytotaxonomically studied in this work. Their karyotypic characters, distinction between the species and the chromosomal basis of sexual differentiation are discussed. The karyotypes of most species are first reported. The results are shown as follows (see Tables 1-4 for the chromosome parameters and the karyotype constitution; Fig. 1 for their idiograms): 1. Smilax nipponica Miq. The species is one of the herbaceous species distributed in East Asia. Two karyotypes, 2n = 26(type A) and 2n = 32 (type B), are found in the species (Plate 1: 1-7). The karyotype of No. 88032 (uncertain of -L--M--S- sexuality) is 2n = 26 = 2m + 6st + 6m + 4sm + 6sm + 2st. The karyotype has 4 pairs of L chromosomes, of which the first three pairs are subterminal, and the 4th is median. The karyotype belongs to 3B. No. 88045 (the male) and No. 88046 (the female) have 2n = 32. Their karyotypes are basically uniform, and both are -L--M-- S 2n=32= 2m+4sm+ 2st+ 2m+4sm+ 6m+ 10sm + 2st, also with 4 pairs of L chromosomes, but the 2nd pair is median, and thus different from the type A. The karyotype belongs to 3B. The first pair of chromosomes of the male are distinctly unequal in length, with the D. V. (0.93) of relative length between them obviously greater than that of the female (0.1). The pair seems to be of sex-chromosomes. Sixteen bivalents (n= 16) were observed at PMCs MI of No. 88045 (Plate 1: 4). The major difference between the karyotypes A and B are greater relative length of L chromosomes in the type A than in the type B, and the increase of chromosome number in the karyotype B mainly due to the increase of st chromosomes. Nakajima (1937)reports 2n= 30 for S. hederacea var. nipponica (=S. nipponica, Wang and Tang, 1980). 2. S. riparia A. DC. This species is also herbaceous, distributed in East Asia. Thirty chromosomes were found in root-tip cells (uncertain of sexuality). The kar -L--M--S-yotype is 2n = 30 = 8st + 6sm + 2st + 6m + 6sm + 2st (Plate 3: 1, 5), consisting mainly of sm and st chromosomes. There are 4 pairs of L chromosomes which are all subterminal and the m chromosomes appear to fall all into S category. Though the karyotype belongs to 3B, it is less symmetrical than that of S. nipponica. The species is karyologically rather different from S. nipponica, therefore. The first pair of chromosomes of this material are unequal in length, and it may be a male. The karyotype of this species is first reported. 3. S. sieboldii Miq. The species is a thorny climbing shrub, distributed in East Asia. At PMCs All, 16 chromosomes (n= 16) were found (Plate 2: 6), in accordance with Nakajima's (1933) report for a Japanese material. 4. S. china L. This species, a thorny climbing shrub, is of a wide distribution range mainly in East Asia and Southeast Asia. Two karyotypes were observed in different populations. (1) The population from Xikou has 2n = 96(6x) = 20st+L- -M- 6t + 6sm + 12st + 52(S) (Plate 3:7), of which the first three pairs of chromosomes are terminal, different from those in the other species. The arm ratios of both L and M chromosomes are larger than 2.0, which resembles those of S. davidiana. (2) PMCs MI of the population from Shangyu shew 15 chromosomes (n 15). The hexaploid of the species is recorded for the first time. Hsu (1967,1971) reported 2n = 30 from Taiwai and Nakajima (1937) recorded n = 30 from Japan, which indicates that the karyotype of the species varies not only in ploidy, but also in number. 5. S. davidiana A. DC. The somatic cells were found to have 32 chromosomes, and PMCs MI shew 16 bivalents (Plate 2: 1-5). The karyotype is 2n = 32=-L- -M- -S 8st + 4sm + 4st + 8sm + 8st. The karyotype belongs to 3B, and is less symmetrical than those in herbaceous species. The D. V. (0.20) of relative length between the two homologues of the first pair is slightly larger in the male than in the female (0.14), and it is thus difficult to determine whether they are sexual chromosomes or not. 6. S. glabra Roxb. The species is a non-thorny climbing shrub, distributed in East Asia and Southeast Asia. 32 chromosomes were found in somatic cells. The -L- -M- - Skaryotype is 2n= 32= 8st + 10st+6sm+8st (Plate 3: 2, 6),with only 3 pairs of sm chromosomes (12, 13 and 16th). The karyotype is more asymmetric than that of S. davidiana, although it is also of 3B (Table 1). The karyotype is first reported for the species. 7. S. nervo-marginata Hay. var. liukiuensis (Hay.) Wang et Tang The variety has a relatively narrow distribution range, mainly occurring in eastern China. The chromosomal number of somatic cells is 2n= 32 (Plate 3: 3-4). The karyotype is -L- -M- -S 2n = 32 = 2sm + 6st + 2sm + 2st + 2m + 6sm + 12st, evidently different from that of S. glabra. The first pair of chromosomes are submedian, and much longer than the 2nd to 4th pairs. The ratio in length of the largest chromosome to the smallest one is 4.3. The symmetric degree is of 3C, a unique type. The karyotype of the species is reported for the first time. In Smilax, the known basic numbers are 13, 15, 16 and 17. The two herbaceous species distributed in East Asia have three basic numbers: 13, 15 and 16, while the woody species studied mainly have 16, with no 13 recorded. Mangaly (1968) studied 8 herbaceous species in North America and reported 2n=26 for them except S. pseudo-china with 2n=30. Mangaly considered that a probably ancestral home of Smilax, both the herbaceous and woody, is in Southeast Asia and the eastern Himalayas, and speculated that the ancestral type of Sect. Coprosmanthus is possibly an Asian species, S. riparia. The karyotypes of the two herbaceous species in East Asia consist mostly of sm and m chromosomes, whereas those for the North American species are all of st chromosomes. Based on the general rule of karyotypic evolution, i.e. from symmetry to asymmetry, his speculation seems reasonable. Researches on sex-chromosomes of Smilax have been carried out since 1930 (Lindsay, 1930; Jensen, 1937; Nakajima, 1937; Mangaly, 1968), and they are generally considered to be the largest pair, but there is still no adequate evidence. The result of our observation on S. nipponica may confirm that the first pair of chromosomes of this species is XY type of sex-chromosomes. Chromosomes of the genus are small and medium-sized, varying between 1-6 μm, slightly larger in herbaceous species than in woody ones, larger in the karyotype of 2n=26 than in that of 2n=32. Based on karyotype constitution of the above 5 species, the karyotype in the genus is characterized by 4 pairs of L chromosomes and 2-5 pairs of M chromosomes, and mostly st and sm chromosomes, and by rather asymmetrical 3B type. The degree of symmetry in the above 5 species is from Sect. Coprosmanthus to Sect. Coilanthus, and herbaceous species towoody ones.     

On the Forest Flora of Zhejiang Province

1. History of development of the forest flora Since the Cenozoic period, the number of forest tree species has steadily risen. In the course of time, some of the archaic types slowly diminished and perished, and new forms gradually evolved. During the palaeocene, the numher of the gymnosperms (with the exception of conifers) and ferns drastically decreased, and that of conifers, on the contrary, increased significantly, and meantime the broad-leaved tree species also appeared. During the Neocene, the angiosperms expanded rapidly and the vegetation gradually shifted towards the mixed deciduous-evergreen forest. Shortly before the Quaternary, there was a series of world-wide climatic fluctuations, as illustrated by progress and retreat of glaciers, cold-resistant and warm-loving (thermophilic) plants appeared alternately. In the post-glaciation period, the zonal distribution of forest vegetation in Zhejiang Province was essentially similar to that of the present time. Excavations from Homu-tu, Yu-Yao County, reveal a luxuriant subtropical forest which existed 7000 years ago. 2. Characteristics of the flora and vegetation (1) Of ancient origin, with rich relic elements. Archaic gymnosperms such as Ginkgo biloba, Amentotaxus argotaenia, Pseudotaxus chienii, Torreya jackii, T. grandis, Taxus chinensis var. mairei, Podocarpus macrophyllus, P. neriifolia, etc, are all found in the Cretaceous deposits. The occurrence of Ginkgo can be traced hack to the Triassic. Most of the conifers, however, were found in the Jurassic, and they have remained to the present time as the main elements of the needleleaved forests. Among the primitive angiosperms, Magnoliaceae is represented by 19 species of 8 genera; Fagaceae and Lauraceae are the dominant evergreen broad-leaved tree species, the former by 6 genera and 43 species, and the latter by 10 genera and 42 species. Hamamelidaceae is represented by 10 genera and 18 species, while Ulmaceae, Tiliaceae, Elaeocarpaceae, by 21 species of 7 genera, 9 species of 2 genera and 6 species of 2 genera respectively. (2) Rich in species and consisting of diverse geographic elements, but dominated by the tropical ones. Throughout Zhejiang Province, there are over 1300 taxa of woody plants (including varieties and cultivated ones) belonging to 109 families and 423 genera. Among them, 8 families with 25 genera and about 45 species, are gymnosperms, and the rest, 101 families with 398 genera and about 1260 species and varieties, are angiosperms. The major angiospermous families include Mognoliaceae, Fagaceae, Lauraceae, Theaceae, Aquifoliaceae and Bambusoideae. Dominant families and genera are the tropical ones, and next in the order, are the East Asiatic, the E. Asia-N. American, then the temperate, the cosmopolitan, endemic and other elements. (3) Rich in endemic species, in monotypic and oligotypic genera. The endemic species include Abies beshanzuensis, Ostrya rehderiana, Carpinus putoensis, Carpinus tientaiensis, Celtis chekiangensis, Calycanthus chinensis, Machilus minutiloba, M. chekiangensis, Semiliquidambar caudata var. cuspidata, Acer aeutum, A. yangjuechi, A. Changhwaense, A. elegantulum, A. pauciflorum, Ilex qinyuanensis, Styrax zhejiangensis, Photinia zhejiangensis, Actinidia zhejiangensis, etc. The monotypic and oligotypic genera are examplified by Ginkgo, Pseudotaxus, Pseudolarix, Fokienia, Cyclocarya, Parakmeria, Pteroceltis, Sargentodoxa, Decaisnea, Aphananthe, Hemiptelea, Zelkova, Fortunearia, Semiliquidambar, Polithyrsis, Ostrya, Heptacodium, Tapiscia, Bretschneidera, Choerospondias, Kalopanax, Halesia, Hovenia, Emmenopterys, Eucommia, Pileostegia, Platycrater, Alniphyllum, etc. The majority of the species mentioned above are rare and precious ones. (4) Introduced species gaining importance Zhejiang Province is mainly situated in the mid-subtropical zone, and from Yukuan District and the Wenzhou Prefecture southwards it belongs to the evergreen broad-leaved south subtropical forest belt. A number of south subtropical species, such as Eucalyptus spp., Casuarina spp., Acacia mearnsii, have been successfully introduced into this region. The introduction of other species, such as Cinnamomum cassia, Grevillea robusta, Michelia alba, Canarium album, Litchi chinensis, Euphoria longan, Kandelia candel, are successful in certain areas. Small plantations of introduced species from S. W. China e.e. Cinnamomum glanduliferum, C. septentrionale have been established. In addition, Metasequoia glyptostroboides, Ulmus pumila, several exotic Pinus species, Carya illinoensis, Robinia pseudoacacia, Amorpha fruficosa, etc. are widely planted throughout Zhejiang Province. In recent years, cold-temperate species such as Chamaecyparis obtusa, Thuja standishii, Thuja occidentalis, Abies firma have been introduced and planted in the mountainous areas. The forest flora of the province is thus being further enriched. 3. Geographical analysis of the forest flora (1) The south part of Zhejiang lies in the transitional belt between the East and South China Floristic Regions, its east part being on the north margin of the South China Floristic Region, and its west part on the south margin of the East China Floristic Region. (2) The north part of the province is weakly influenced by the temperate elements, but the influence may extend to the central part of this province as the elevation there is higher. (3) Diverse floristic elements such as those belonging to Japan, Taiwan (China), C. China and S. W. China regions also occur in the province, especially in its western and eastern parts.     

Studies on the Pollen Morphology of Trapa from Zhejiang

In the present work, pollen grains of 9 species of Trapa L. from Zhejiang were examined under LM and SEM. They are subsphaeroidal or subprolate, obtuse-triangular in polar view, elliptic or subrounded in equatorial view, and 3-colpate. In the equatorial area, there are three ridge-shaped appendages which elongates along apertures toward two poles and ultimately combined, the ornamentation of other part of exine is minute-verrucate. The genus Trapa is uniform in shape of pollen grains, type and position of apertures and ornamentation of exine, while differentiation can be found in size of pollen grains and shape of ridge-shaped appendage. All of these provide valuable evidence for the classification of Trapa and the verification of their affinities. The validity of Trapaceae, the evolutionarytrends of pollen morphology and the affinities of some species are discussed in this paper.     

浙江植物引种驯化研究进展与思考

引种驯化是增加植物资源的一种传统育种方法。本文从浙江省农业科学院亚热带作物研究所引种驯化研究发展回顾入手,剖析了温州植物引种结果,以方法的改进反映浙江现代引种驯化学术水平的进步,最后讨论了植物引种驯化研究的若干问题。     

浙江茎蝇科一新种(双翊目：茎蝇科)

该文记述了浙江省茎蝇科一新种天目长角茎蝇Loxocera tianmuensis模式标本保存在中国农业大学昆虫标本馆。     

浙江省两栖动物新纪录——小棘蛙

摘要：2010年6月26日,在浙江省百山祖国家级自然保护区采得棘蛙属（Paa）标本2只,均为雄性,经鉴定为小棘蛙（P.exilispinosa）,为浙江省两栖类新纪录。     

浙江省分布1新记录科——霉草科

报道了中国浙江省种子植物区系1新记录科,含1新记录属和2新记录种,即霉草科(Triuridaceae)喜荫草属(Sciaphila),大柱霉草(Sciaphila secundiflora Thwait.ex Benth.)和多枝霉草(S.ramosa Fukuyama et Suzuki)。凭证标本存放于浙江自然博物馆标本室(ZM)。     

浙江薹草属（莎草科）新分类群

摘要描述及图解了浙江薹草属Carex 5新种和1新变种,它们是：灰帽薹草组sect. Mitratae Kükenth.的天目山薹草Carex tianmushanica C. Z. Zheng & X. F. Jin和拟三穗薹草C. pseudotristachya X. F. Jin & C. Z. Zheng;匏囊薹草组sect. Lageniformes (Ohwi) Nelmes的密毛薹草C. densipilosa C. Z. Zheng & X. F. Jin;菱形果薹草组sect. Rhomboidales Kükenth.的浙南薹草C. austrozhejiangensis C. Z. Zheng & X. F. Jin和朝芳薹草C. chaofangii C. Z. Zheng & X. F. Jin;疏花薹草组sect. Laxiflorae Kunth的无芒长嘴薹草C. longerostrata C. A. Mey. var. exaristata X. F. Jin & C. Z. Zheng。     

浙江天目地黄2新变型

描述了产于浙江临安的天目地黄2个新变型--白花天目地黄(Rehmannia chingii Li f.albi flora G.Y.Liet D.D.Ma)和紫斑白花天日地黄(R.chingii Li f.purpureo-punctata G.Y.Li et G.H.Xia),它们与原变型的主要区别为花冠白色;前者喉部淡黄色,后者喉部具紫色斑点.     

热带气旋对浙江省农业影响的风险区划

依据自然灾害风险系统分析理论、热带气旋和农业经济资料,综合灾害风险指数法,在分析热带气旋对浙江省农业影响的致灾因子的危险性、孕灾环境的暴露性、承灾体的脆弱性和防灾减灾能力的基础上,应用加权综合法得到不同网格的综合风险度指数.基于GIS技术,开展了热带气旋对浙江省农业影响的风险区划.结果表明:致灾因子危险性的最大值分布在浙江东南沿海,孕灾环境暴露性的最大值分布在丽水山区,承灾体脆弱性的最高值分布在杭州、绍兴市区以及兰溪市,防灾减灾能力的最高值主要分布在杭州、宁波、温州市区及其周边地区.综合考虑各因子的综合风险度,热带气旋对浙江省农业影响的风险可分为高风险、次高风险、中等风险、次低风险和低风险5个等级.该研究可为浙江省农业结构调整和防灾减灾提供科学依据.