云南四药门花属—新种

云南四药门花属—新种钱义咏（云南省思茅行署林业局，思茅６６５０００）ＡＮＥＷＳＰＥＣＩＥＳＯＦＴＥＴＲＡＴＨＹＲＩＵＭＦＲＯＭＹＵＮＮＡＮ￥ＱＩＡＮＹｉ－Ｙｏｎｇ（ＳｉｍａｏＡｄｉｍｉｎｉｓｔｒａｔｉｖｅＯｆｆｉｃｅＦｏｒｅｓｔｒｙＢｕｒｅａｕ，Ｙｕ...     

大穗崖豆一新变种

大穗崖豆一新变种钱义咏（云南省思茅行署林业局,思茅县６６５０００）关键词多小叶大穗崖豆ＡＮＥＷＶＡＲＩＥＴＹＯＦＭＩＬＬＥＴＴＩＡＭＡＣＲＯＳＴＡＣＨＹＡ￥ＱｉａｎＹｉｙｏｎｇ（ＦｏｒｅｓｔｒｙＢｕｒｅａｕｏｆＳｉｍａｏＡｄｍｉｎｉｓｔｒａｔｉｖｅＯ...     

云南伪针茅属一新种

云南伪针茅属一新种钱义咏（云南省思茅行署林业局,思茅县６６５０００）关键词伪针茅属;思茅伪针茅ＡＮＥＷＳＰＥＣＩＥＳＯＦＰＳＥＵＤＯＲＡＰＨＩＳＦＵＯＭＹＵＮＮＡＮ￥ＱｉａｎＹｉｙｏｎｇ（ＦｏｒｅｓｔｒｙＢｕｒｅａｕ,ＳｉｍａｏＡｄｍｉｎｉｓｔｒａｔ...     

云南蛇菰属─新种

云南蛇菰属─新种钱义咏（云南省思茅行署林业局,云南思茅６６５０００）关键词蛇菰属;澜沧蛇菰;新种澜沧蛇菰新种图１ＡＮＥＷＳＰＥＣＩＥＳＯＦＢＡＬＡＮＯＰＨＯＲＡＦＲＯＭＹＵＮＮＡＮ￥ＱｉａｎＹｉｙｏｎｇ（ＦｏｒｅｓｔｒｙＢｕｒｅａｕｏｆＳｉｍａｏＡｄ...     

农业系统生产力（ASP）的量化及其现状分析

农业系统生产力（ＡＳＰ）的量化及其现状分析卢进登,韩纯儒（北京农业大学农学系,１０００９４）ＱｕａｎｔｉｆｉｃａｔｉｏｎｏｆＡｇｒｏｓｙｓｔｅｍＰｒｏｄｕｃｔｉｖｉｔｙ（ＡＳＰ）ａｎｄＡｎａｌｙｓｉｓｏｎｉｔｓＣｕｒｒｅｎｔＳｉｔｕａｔｉｏｎｉｎＣｂｉｎａ￥．ＬｕＪｉｎ－ｄｅｎｇ;ＨａｎＣｈｕｎｒｕ（ＢｅｉｊｉｎｇＡｇｒｉｃｕｌｔｕｒａｌＵｎｉｖｅｒｓｉｔｙｆＢｅｉｊｉｎｇ１０００９４）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（２）：２１－２２．ＢａｓｅｄｏｎａｂｒｉｅｆａｎａｌｙｓｉｓｏｎｔｈｅｆｏｒｍａｔｉｏｎｐｒｏｃｅｓｓｏｆＡＳＰ,ｉｔｓｃｏｎｃｅｐｔｉｓｄｅｓｃｒｉｂｅｄａｎｄａｎｉｎｔｅｇｒａｔｅｄｉｎｄｉ－ｃａｔｏｒｆｏｒｉｔｓｑｕａｎｔｉｆｉｃａｔｉｏｎ—ＡＳＰ２ｉｓｐｕｔｆｏｒｗａｒｄｓ．Ｆｒｏｍｔｈｏｓｅ,ｔｈｅＡＳＰｌｅｖｅｌｓｉｎｖａｒｉｏｕｓｒｅｇｉｏｎｓｏｆＣｈｉｎａａｒｅａｎａｌｙｚｅｄａｎｄ８ｌｅｖｅｌｓａｒｅｄｉｖｉｄｅｄｂｙｕｓｉｎｇ．Ｈｉｅｒａｒｃｈｉｃｃｌｕｓｔｅｒｉｎｇｍｅｔｈｏｄ．Ｉｔ’ｓ：ｃｌａｒｉｆｉｅｄｔｈａｔＡＳ－ＰＩｉｓａｍｏｒｅ     

生态农业与乡村经济持续发展

生态农业与乡村经济持续发展张壬午,计文瑛,孙鸿良（天津农业部环境保护研究所,３００１９１）（中国农科院,北京１０００８１）ＥｃｏｌｏｇｉｃａｌＡｇｒｉｃｕｌｔｕｒｅａｎｄＳｕｓｔａｉｎａｂｌｅＤｅｖｅｌｏｐｍｅｎｔｏｆＲｕｒａｌＥｃｏｎｏｍｙ￥．ＺｈａｎｇＲｅｎｗｕ;ＪｉＷｅｎｙｉｎｇ（Ａｇｒｏ－ｅｎｖｉｒｏｎｍｅｎｔＰｒｏｔｅｃｌｉｏｎＩｎｓｔｉｔｕｔｅ,Ｔｉａｎｊｉｎ３００１９１）,ＳｕｎＨｏｎｇｌｉａｎｇ（ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＡｇｒｉｃｕｌｔｕｒａｌＳｃｉｅｎｃｃｓ,Ｂｅｉｊｉｎｇ１０００８１）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（２）：１９—２０．ＴｈｉｓｐａｐｅｒｂｒｉｅｆｌｙｐｒｅｓｅｎｔｓｔｈｅｃｕｒｒｅｎｔｄｅｖｅｌｏｐｍｅｎｔｏｆｅｃｏｌｏｇｉｃａｌａｇｒｉｃｕｌｔｕｒｅｉｎＣｈｉｎａａｎｄｃｏｍｐａｒｅｓｗｉｔｈｔｈｅ＇＇ｓｕｓｔａｉｎａｂｌｅａｇｒｉｃｕｌｔｕｒｅａｎｄｒｕｒａｌｄｅｖｅｌｏｐｍｅｎｔ＇＇（ＳＡＲＤ）ｐｕｔｆｏｒｗａｒｄｂｙＦＡＯ,Ｃｈｉｎａ’ｓｓｕｓｔａｉｎａｂｌｅａ－ｇｒｉｃｕｌｔｕｒｅｉｓｎｏｔｏｎｌｙａｎｉｎｇｅｎｉｏｕｓ     

最大概率原理在农田生态系统中的应用

最大概率原理在农田生态系统中的应用姚建民（山西省农科院农业资源综合考察研究所,太原０３０００６）马蓉丽（山西省农科院蔬菜研究所,太原０３０００６）ＡｐｐｌｉｃａｔｉｏｎｏｆＭａｘｉｍｕｍＰｒｏｂａｂｉｌｉｔｙＰｒｉｎｃｉｐｌｅｉｎＦａｒｍｌａｎｄＥｃｏｓｙｓｔｅｍ￥．ＹａｏＪｉａｎｍｉｎ（ＩｎｓｌｉｌｕｔｅｆｏｒＣｏｍ－ｐｒｅｈｅｎｓｉｖｅＳｕｒｖｅｙｏｆＡｇｒｉｃｕｌｔｕｒａｌＲｅｓｏｕｒｃｅｓ,ＳｈａｎｘｉＡｃａｄｅｍｙｏｆＡｇｒｉｃｕｌｔｕｒａｌＳｃｉｅｎｃｅｓ,Ｔａｉｙｕａｎ０３０００６）,ＭａＲｏｎｇｌｉ（ＩｎｓｌｉｔｕｔｅｏｆＶｅｇｅｔａｂｌｅＲｅｓｅａｒｃｇｈ,ＳｈａｎｘｉＡｃａｄｅｍｙｏｆａｇｒｉｃｕｌｔｕｒａｌＳｃｉｅｎｃｅｓ,Ｔａｉｙｕａｎ（０３０００６）．Ｃｈｉｎｅｓｅ,ＪｐｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（４）：５８－６０．Ｉｎｏｒｄｅｒｔｏｓｔｒｅｎｇｔｈｅｎｔｈｅｐｒａｃｔｉｃａｂｉｌｉｔｙｏｆｍａｘｉｍｕｍｐｒｏｂａｂｉｌｉｔｙｐｒｉｎｃｉｐｌｅ,ｔｈｉｓｐａｐｅｒｇｉｖｅｓｏｕｔｓｏｍｅｅｓ－ｓｅｎｔｉａｌｃｏｎｄｉｔｉｏｎｓｎｅｅｄｅｄｆｏｒａｐｐｌｙｉｎｇｔｈ     

东北地区蒿属植物比较形态学研究——II.叶表皮结构

本通过扫描电子显微镜,对东北地区蒿属（Ａｒｔｅｍｉｓｉａ）植物,莳萝蒿组（Ａ．ｓｅｃｔ．Ａｂｓｉｎｔｈｉｕｍ ＤＣ）,艾蒿组（Ｓｅｃｔ．Ａｂｒｏｔａｎｕｍ Ｂｅｓｓ）,艾组（Ｓｅｃｔ．Ａｒｔｅｍｉｓｉａ）,龙蒿组（Ｓｅｃｔ．Ｄｒａｃｕｍｃｕｌｕｓ Ｂｅｓｓ）,牡蒿组（Ｓｅｃｔ．ｌａｔｉｏｂｕｓ Ｙ．Ｒ．Ｌｉｎｇ）３６种成熟代表植物叶表皮形态学特征进行了详尽的比较研究。其中表皮细胞大小、形状不等。     

异细胞质信息八倍体小偃麦（Trititrigia 8x）的选育及其性状与细胞遗传

本实验用普通小麦“中国春”和八种异细胞质“中国春”（Ａｅｇｉｌｏｐｓ ｖａｖｉｌｏｖｉｉ）ＣＳ,（Ａｅ．ｊｕｖｅｎａｌｉｓ）ＣＳ,（Ａｅ．ｃｒａｓｓａ）ＣＳ,（Ａｅ．ｃｏｍｏｓａ）ＣＳ,（Ａｅ．ｕｎｉａｒｉｓｔａｔａ）ＣＳ,（Ａｅ．ｓｐｅｌｔｏｉｄｅｓ．Ｍ．）ＣＳ,（Ａｅ．ｋｏｔｓｃｈｙｉ）ＣＳ．（Ｔ．ｔｉｍｏｐｈｅｅｖｉ）ＣＳ分别与八倍体小偃麦（Ｔｒｉｔｉｔｒｉｇｉａ ８ｘ）“远中２”、“远中４     

生物固氮─—生态农业的一个重要启动因素

生物固氮─—生态农业的一个重要启动因素陈士平（辽宁省农业科学院土壤肥料研究所,沈阳１１０１６１）ＢｉｏｌｏｇｉｃａｌＮｉｔｒｏｇｅｎＦｉｘａｔｉｏｎ—ＡｎＩｍｐｏｒｔａｎｔＲｕｎｎｉｎｇＦａｃｔｏｒｏｆＥｃｏｌｏｇｉｃａｌＡｇｒｉｃｕｌｔｕｒｅ￥．ＣｈｅｎＳｈｉｐｉｎｇ（ＳｏｉｌａｎｄＦｅｒｔｉｌｉｚｅｒＩｎｓｔｉｌｕｔｅ,ＬｉａｏｎｉｎｇＡｃａｄｅｍｙｏｆＡｇｒｉｃｕｌｔｕｒａｌＳｃｉｅｎｃｅｓ,Ｓｈｅｎｙａｎｇ１１０１６１）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（２）：３１—３３．ＬｅｇｕｍｉｎｏｕｓｇｒｅｅｎｍａｎｕｒｅｃｒｏｐｓｓｕｃｈａｓｓｗｅｅｔｃｌｏｖｅｒａｎｄＡｓｔｒａｇａｌｕｓｈｕａｎｇｈｅｅｎｓｉｓ,ｃａｎｐｒｏｖｉｄｅｄｅｆｉｎｉｔｅａｍｏｕｎｔｏｆｂｉｏｌｏｇｉｃａｌｌｙｆｉｘｅｄ－ＮｔｏｍａｋｅＮ－ｂｕｄｇｅｔｂａｌａｎｃｅ,ｐｒｏｍｏｔｅｓｏｉｌｐｈｙｓｉｃａｌａｎｄｃｈｅｍｉｃａｌｐｒｏｐｅｒ－ｔｉｅｓ,ｒｅｄｕｃｅｓｏｉｌａｎｄｗａｔｅｒｅｒｏｓｉｏｎ,ａｎｄｔｈｕｓ,ｉｎｃｒｅａｓｅｐｅｒｕｎｉｔａｒｅａｙｉｅｌｄａｎｄｔｏｔａｌｏｕｔｐｕｔｗｈｅ     

内蒙古沙参属一新异名和一新名称

索伦沙参Adenophora suolunensis P. F. Tu &; X. F. Zhao与小花沙参A. micrantha D. Y. Hong为同一种植物, 故将前者处理为后者的异名; 坛盘沙参A. urceolata Y. Z. Zhao是壶花沙参A. urceolata C. Y. Wu的晚出同名, 另提出新名库伦沙参A. kulunensis Y. Z. Zhao。     

裂叶沙参和泡沙参种群有性生殖和无性繁殖的比较

通过对裂叶沙参(Adenophora lobophylla Hong)和泡沙参(A.potaninii Korsh.)种群有性生殖和无性繁殖特性的对比,揭示濒危植物裂叶沙参的种群内部致濒机制。结果表明:裂叶沙参种群幼苗抢占草本层上层空间能力弱于泡沙参种群;裂叶沙参种群是以相对长的生殖期和高产籽量来适应环境;裂叶沙参种群开花结实量虽高于泡沙参种群,但其中成熟种子少,种子质量差,致使其种群由种子到一年生幼苗的转化率极低,并且幼苗生活力弱,是导致其种群濒危的重要内部原因。裂叶沙参种群除有性生殖外还兼有较弱的无性繁殖,是对其有性生殖的一个重要补充。     

Comparative Studies of Sexual Reproduction and Asexual Propagation Between Populations of Adenophora lobophylla and A. potaninii

To reveal the internal mechanism which lead to the endangerment of the AdenophoUa lobophylla Hong population, comparative studies of sexual reproduction and asexual propagation between the populations of A. lobophylla and A. potaninii Korsh were carried out. Young seedlings of A. lobophylla had less ability to occupy the uper space of the herbaceous layer than those of A. potaninii. The A. lobophylla population produced much more seeds and lived a long reproductive life to adapt the ambient environment. Though the number of flowers and fruits of A. lobophylla population was more than those of A.potaninii population, the number of its ripe seeds as well as the quality was less. Thus, the development rate from its seeds to one-year old seedlings was very low, and viability of its young seedlings was very poor. This could be the important factor causing the imminent population endangerment of A. lobophylla. Besides the sexual reproduction, the A. lobophylla population also had a comparatively tiny ability of asexual propagation, which was advantageously complementary to its sexual reproduction.     

用核糖体DNA的ITS序列探讨裂叶沙参的系统位置——兼论ITS片段在沙参属系统学研究中的价值

本文采用PCR直接测序方法,对来自沙参属全部2组7亚组的10个种和作为外类群的风铃草属2个种的核糖体DNA　ITS片段进行了序列分析。在重点探讨裂叶沙参分类地位的同时,分析了ITS片段序列在沙参属系统发育重建中的价值。结果表明,在沙参属中,ITS片段在长度、GC含量和位点变异量上均比较一致;长度539bp～541 bp,GC含量57％～60％,信息位点只占总位点的3．9～6％。采用PAUP软件进行的系统发育分析表明,裂叶沙参A．lobophylla与大花盘亚组的A．himalayana组成一支,而不是象以往形态学和杂交试验所推断的与泡沙参A．potaninii或A．stenanthina近缘。可见,ITS序列进一步支持将裂叶沙参移出泡沙参复合体甚至移出有齿亚组的推论,但同时也表明将其作为A．stenanthina的近缘种是不适宜的。尽管本研究所测定的类群已涵盖了整个沙参属,但种间序列的两两比较表明,沙参属种间在ITS片段上的分化很小(0.0～3.9％),相比之下,沙参属类群与风铃草属类群间的分化却很高(17.8％～19.2％)。这大概和沙参属起源较晚、遗传分化较小有关。本文还就ITS片段在沙参属和桔梗科系统学研究中的价值进行了讨论。     

A Reevaluation of the Status of A. lobophylla Based on ITS Sequence,with Reference to the Utility of ITS Sequence in Adenophora

Adenophora Fisch. (Campanulaceae)is a medium-sized and diverse genus, which occurs mainly in eastern Asia, particularly in China. Although several taxonomic systems have been proposed, there is still much debate on the delimitation and systematic arrangement of the species within the genus, due mainly to high variation in morphology, habitats, phenotypic plasticity, and potential hybridization. A. lobophylla Hong is a rare perennial endemic to several counties of Sichuan, China. Since this species was recognized, much work has been done on its taxonomic status, including morphology, crossing experiment and allozymes. However, evidence available is not concordance so far, and its relationship with other species within the genus remains largely uncertain. In the present paper, the internal transcribed spacer(ITS) region of 18s～26s nuclear ribosomal DNA was sequenced in 10 representatives of Adenophora and two outgroup species of Campanula to assess its utility for phylogenetic reconstruction in Adenophora, in addition to reevaluation of the taxonomic status of A. lobophylla. The results indicate that there exist high sequence alignability and length conservation among ITS sequences, with informative sites being 3.9% and length ranging from 539 to 541 bp and G + C content varying from 57% to 60%. Phylogenetic　analyses using Fitch parsimony show that A. lobophylla is closely related to A. himalayana instead of A. potaninii or A. stenanthina as revealed by previous morphological work and crossing experiment. The ITS phylogeny is generally congruent with other evidence in that A. lobophylla should be removed from the A. potaninii complex or even subsect. Microdiscus. Its appropriate placement, however, should be further explored. In pairwise comparisons at unambiguously aligned sites, sequence divergence was relatively low among Adenophora species with the values ranging from 0.0 to 3.9% in spite of the fact that the species surveyed covered all of the sections and subsections of the genus. In contrast, high sequence divergence is found among Adenophora and Campanula species with the values from 17.8 % to 19.2 %. The low divergence among Adenophora species is justified considering its recent origin, and also suggests that ITS sequence would provide a promising source of nuclear phylogenetic markers to reconstruct the phylogeny within Campanulaceae on the tribe and family levels.     

中国沙参属花粉形态的研究

对分布于我国的沙参属３２种（亚种,变种）植物的花粉形态进行了光学显微镜和扫描电镜的观察,研究结果表明：（１）沙参属植物花粉形态较相似,但其外壁纹饰,厚度,小刺密度,萌发孔情况在种,亚种,变种鉴别上有一定的意义。（２）本属花粉粒演化趋势为：表面条网状,条脊窄,小刺多,网孔类圆形→表面条状,脑纹状,条脊宽,小刺少,网孔不规则形。（３）花粉形态结合植物形态和染色体演化趋势,推断本属各组的演化关系为：基生     

国产沙参属五个种的核型研究

首次报道了５种国产沙参属（Ａｄｅｎｏｐｈｏｒａ）植物的染色体数目和核型。北方沙参Ａ．ｂｏｒｅａｌｉｓＨｏｎｇｅｔＹ．Ｚ．Ｚｈａｏ的核型公式为２ｎ＝３４＝２８ｍ＋４ｓｍ（２ｓａｔ）＋２ｓｔ（２ｓａｔ）;雾灵沙参Ａ．ｗｕｌｉｎｇｓｈａｎｉｃａＨｏｎｇ的核型公式为２ｎ＝３４＝２６ｍ（４ｓａｔ）＋６ｓｍ＋２ｓｔ或２ｎ＝３４＋１Ｂ＝２６ｍ（４ｓａｔ）＋６ｓｍ＋２ｓｔ＋１Ｂ;秦岭沙参Ａ．ｐｅｔｉｏｌａｔａＰａｘｅｔＨｏｆｍ．的核型公式为２ｎ＝３４＝２６ｍ（２ｓａｔ）＋６ｓｍ＋２ｓｔ或２ｎ＝３４＋１Ｂ＝２６ｍ（２ｓａｔ）＋６ｓｍ＋２ｓｔ＋１Ｂ;裂叶沙参Ａ．ｌｏｂｏｐｈｙｌａＨｏｎｇ的核型公式为２ｎ＝３４＝２６ｍ＋４ｓｍ（２ｓａｔ）＋４ｓｔ或２ｎ＝３４＋２Ｂ＝２６ｍ＋４ｓｍ（２ｓａｔ）＋４ｓｔ＋２Ｂ。泡沙参Ａ．ｐｏｔａｎｉｎｉＫｏｒｓｈ的核型公式为２ｎ＝３４＝２８ｍ（２ｓａｔ）＋４ｓｍ＋２ｓｔ。它们同以往报道的其它种的核型相似：以中部着丝点染色体（ｍ）为主,至少具一对近端着丝点染色体（ｓｔ）和一对随体染色体,核型的对称程度较高,着丝点端化值（Ｔ．Ｃ）为５８．４％～６２．０％。结合其它性状,讨论了裂叶沙参的特殊性     

泡沙参同工酶基因位点的遗传分析

利用聚丙烯酰胺凝胶电泳技术 ,对来自天然群体 (居群 )的泡沙参 (Adenophora potaninii Korsh.)及其人工杂交子代进行了 8种同工酶的电泳检测和谱带遗传分析 ,以确定编码这些酶系统的基因位点和等位基因。选用 4种不同的凝胶缓冲系统 ,对下列不同酶系统进行了酶谱的遗传分析 :天冬氨酸转氨酶 (AAT)、酯酶 (EST)、甲酸脱氢酶 (FDH)、谷氨酸脱氢酶 (GDH)、异柠檬酸脱氢酶 (IDH)、乳酸脱氢酶(LDH)、苹果酸酶 (ME)和超氧化物歧化酶 (SOD)。结果表明 ,这 8种酶系统至少由 1 8个基因位点编码 ,其中 1 2个位点为遗传稳定的等位酶位点 ,是可靠的遗传标记。酶谱的分离式样表明 ,EST为单聚体结构 ,AAT、FDH、IDH、SOD为二聚体结构 ,GDH为六聚体结构。最后对同工酶的器官和发育特异性以及同工酶基因位点的遗传分析进行了讨论     

Genetic Analysis of Isozyme Loci in Adenophora potaninii Korsh.

Enzyme polymorphism in Adenophora potaninii Korsh. was investigated using vertical slab polyacrylamide gel electrophoresis. Genetic analysis of the population samples and the progeny of intraspecific crosses allowed the verification of the isozyme loci from eight enzyme systems. The system studies included aspartate aminotransferase (AAT), esterase (EST). formate dehydrogenase (FDH), glutamate dehydrogenase (GDH), isocitrate dehydrogenase (IDH), lactate dehydrogenase (LDH), malic enzyme (ME) and superoxide dismutase (SOD). The results indicated that the eight enzyme systems are specified by at least 18 loci, 12 of which behaved as al|ozyme loci. Zymogram patterns showed that EST is monomeric and GDH is hexameric. AAT, FDH, IDH and SOD are apparently dimeric. The tissue and developmental variability are also discussed along with the genetic analysis of isozymes.     

桔梗科4种植物分离配囊的比较研究

应用酶解技术分离出桔梗科四种植物(桔梗、轮叶沙参、杏叶沙参和羊乳)的胚囊。对胚囊的形态结构和贮藏物质的变化作了观察比较。它们的成熟胚囊结构基本相同,均由卵细胞、一对助细胞和中央细胞组成。反足器退化较早。但形态、大小等有一定差异。桔梗胚囊狭长,细胞质浓密;沙参(包括轮叶沙参与杏叶沙参)的胚囊也较狭长,细胞质不如前者浓密;羊乳胚囊非常宽大,而细胞质相当稀薄,与前三种植物的差异较大。它们均含有贮藏物质,显微化学反应表明主要系多糖物质。多糖颗粒的形状、大小各有特点,在胚囊受精前后的消长变化也有不同。其中羊乳与其它三种植物之间的差别较大。