子叶的

0Mg/L 6-benzylaminopurine was the optimal concentration of shoots quantity inducing which frequency of inducing shoots and number of shoots per explant were 100% and 11.1 respectively. 0.5mg/L 6-benzylaminopurine was the optimal concentration of shoots length inducing which average length of shoots was 12.0mm. Explant size had significantly effects on direct shoots quantity and length induction. When complete cotyledon used as explant, frequency of inducing shoots, number of shoots per explant and average length of shoots could approach to 100%, 6.7 and 17.1mm respectively. 2.0mg/L silver nitrate could significantly increase shoot quantity induction, both frequency of inducing shoots and number of shoots per explant could be as high as 97.2% and 4.2 respectively. But silver nitrate also could restrain shoots elongation.

结果表明：不同黄瓜品种直接不定芽数量诱导存在显著差异，但长度诱导无显著差异；6-苄氨基嘌呤对直接不定芽数量和长度的诱导作用显著，其中4.0mg/L为数量诱导适宜浓度，其出芽率和每外植体出芽数达到最高，分别为100.0%和11.1，0.5mg/L为长度诱导适宜浓度，其平均芽长12.0mm；外植体的大小对直接不定芽数量和长度均具显著影响，随着子叶的增大诱导直接不定芽的数量和长度增加，其中单片完整子叶为最适宜大小，其出芽率、每外植体出芽数和平均芽长分别达到100%、6.7和17.1mm；硝酸银也对直接不定芽数量诱导影响显著，其中2.0mg/L为适宜浓度，出芽率和每外植体出芽数分别达到97.2%和4.2，但对芽长有抑制作用。

Genus of flowering plants having a single cotyledon in the seed.

种子中有一片子叶的开花植物属。

It was found that both excised and intact cotyledon enlarged apparently under light especially WL, BL and RL.

在白光、红光、蓝光下KT对子叶的扩大效应明显。

B Of the six basic media MS, MS1/2 (half-strength of MS salts and vitamins), WPM, DKW, B5 and SH, MS1/2 was the most proper one to induce somatic embryos. Somatic embryos generally regenerated directly from excised zygotic cotyledons. PGRs combination affected somatic embryogenesis significantly. Medium with NAA 1mg/L, TDZ 0.05mg/L, IBA 2—10mg/L combined with BA 10mg/L, or IBA 10mg/L integrated with BA 0-2mg/L gave the highest induction rate. Excised zygotic hypocotyls had the strongest potential to produce callus. Callus induction was also affected significantly by media and PGRs. The proper callus induction condition was MS1/2 medium containing NAA 1mg/L, IBA 10mg/L, BA 2-5mg/L and TDZ 0.05mg/L. Harvest period affect somatic embryogenesis significantly. Zygotic embryo explants collected from the end of July to the middle of August had strong potential to generate somatic embryos, when endosperm finished solidification, different parts of the embryos were completely formed, the size of embryos occupied about 2/3 of the embryo sac. Provided with optimized conditions, direct somatic embryogenesis rate can attain to 33. 68%, and callus induction rate of hypocotyls was up to 90.7%. Cytological observation on megasporogenesis and zygotic embryogenesis of Manchurian ash showed that the ovary was twicarpellum, twilocular with two ovules each loculus. The ovule was tenuinucellar and anatropous, with one megasporcocyte. The development of embryo sac is of the Polygoum type.

体细胞胚胎发生研究的结果表明：(1)成熟过程中的合子胚是诱导水曲柳体细胞胚胎发生的最佳外植体材料；(2)在所试验到的MS、MS1/2（将MS的所有成分均减半）、WPM、DKW、B〓、SH等六种基本培养基中，MS1/2是最适合诱导水曲柳体细胞胚胎发生的基本培养基；(3)水曲柳的体细胞胚胎发生以直接发生为主，体细胞胚主要来自于从合子胚分离的完整子叶；(4)培养基中的激素组合对水曲柳的体细胞胚胎发生有显著影响，诱导直接体细胞胚发生较好的激素组合有NAA 1mg/L+IBA 2，5，10mg/L+BA 10mg/L+TDZ 0.05mg/L和NAA 1mg/L+IBA 10mg/L+BA 0，2mg/L+TDZ 0.05mg/L；(5)合子胚分离的下胚轴具有最强的愈伤组织诱导潜力，少数愈伤组织可以分化出体细胞胚；(6)愈伤组织的诱导也受培养基和激素配比的显著影响，最适宜诱导的培养条件为MS1/2+NAA 1mg/L+IBA 10mg/L+BA 2，5mg/L+TDZ0.05mg/L；(7)采种时间对体细胞胚胎发生有显著影响。7月末到8月中旬的合子胚具有较强的体细胞胚发生潜力，此时种子尚未成熟，胚乳已呈固态，种胚的各个部分已分化完全，种胚体积占胚腔的大约2/3；(8)在各自综合的最适条件下，完整子叶的体细胞胚诱导率可达33.68%，下胚轴的愈伤组织诱导率可达90.7%。

Further examinations of cell size, trichome distribution and meristematic activity failed to find any differences between cotyledons of European species. All observations showed that both cotyledons of European Gesneriaceae species ceased to grow in early stages and thus no prolonged meristematic activity could be observed.

进一步检测子叶的细胞大小、毛状物的分布、及分生组织活性检测均显示欧洲苦苣苔科成员的两片子叶在发育早期已停止生长，两片子叶间也无形态上明显的差异，同时也无法观察到持续的分生组织活性刺激子叶持续生长。

Plantlet regeneration from cotyledon of Citrullus lanatus cv. Zhangkang No. 4 was studied. The results showed that aseptic seedlings should be cultured in dark for 3d, then exposed to a photoperiod of 16/8h/d for 3d. The callus induction rate was higher in cotyledons placed facing downwards to the medium than in those facing upwards. The highest induction rate occurred in MS medium containing 6-BA (2.0mg/L), kinetin (1.0mg/L)and GA3 (1.0mg/L). The induction initiated in dark and took 7 days, while callus growth and differentiation proceeding for 7 days under 16/8h light-dark cycles. A highest rate of embryogenic callus was obtained after 3 successive subcultures.

以无子西瓜郑抗4号无菌苗子叶为外植体，进行了体细胞胚发生及植株再生的研究，结果表明，无菌苗应先进行3d暗培养，然后采取光照16h/d和黑暗8h/d培养3d；将子叶的叶面朝下放置于培养基上的愈伤组织诱导率高于叶面朝上的培养方式；子叶诱导胚性愈伤组织的最适培养基配方为MS+6-BA2.0mg/L+KT1.0mg/L+GA31.0mg/L；诱导需要在黑暗条件下启动，进行7d暗培养，而生长分化于光照16h/d和黑暗8h/d条件下培养7d；继代3次得到的胚性愈伤组织最多；最适生根培养基配方为1/2MS+IBA0.3mg/L。

OBJECTIVE Study on the chemical constituents of the leaves of Elaeagnus pungens Thunb.

目的 研究胡颓子叶的化学成分。

Somatic embryogenesis of Parthenocissus tricuspidata is studied in this paper.

该文以爬山虎子叶的叶片和叶柄为试验材料，对爬山虎体细胞胚发生进行了研究。

The experiments showed that there were differences in number, size and shape of cotyledons.

在子叶的大小上，有的2片子叶大小基本相似，有的则差异明显。

Whether the variations in cotyledons are caused by physiological or genetic factors must await more research.

子叶的变异是遗传原因还是生理影响尚需进一步研究。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。