牦牛胎儿肺脏发育的形态学研究

本实验选取40份不同胎龄的牦牛肺脏样本,通过组织学和组织化学的方法对牦牛肺发育过程进行研究,旨在为发育生物学提供形态学资料.结果表明,牦牛胚胎肺发育可分为5个时期:(1)胚胎期(30～50 d),胚胎出现肺芽,其分支形成主支气管,进一步分出叶支气管,上皮均为假复层柱状上皮; (2)假腺期(50～120 d),支气管树发育明显,末端终蕾结构似腺体,为假复层柱状上皮;(3)小管期(120 ～180 d),呼吸部发育明显,终蕾腺泡样结构消失,可见多处管状分支,上皮为单层柱状或单层立方;(4)囊状期(180 ～220d),终囊管壁由较厚肺泡隔及原始肺泡组成,少数原始肺泡上皮分化为扁平的肺泡Ⅰ型细胞和立方形的肺泡Ⅱ型细胞;(5)肺泡期(220 ～ 260 d),形成肺泡,大部分上皮细胞分化为扁平的肺泡Ⅰ型细胞和立方形的肺泡Ⅱ型细胞.胚胎期和假腺期支气管和终蕾上皮的糖原含量丰富,从小管期开始,上皮细胞糖原含量开始急剧减少.之后的几个时期,只有导气部个别上皮细胞PAS反应呈阳性.实验结果表明:牦牛胎儿的肺脏发育的特点与普通牛的基本相似,主要不同点是牦牛的囊状期较短,肺泡期较长,即牦牛胎儿的肺脏更早发育成熟.     

野生玫瑰果实发育过程中种子的细胞组织结构和内源激素变化对其休眠性的影响

以吉林珲春自然群落的野生玫瑰(Rosa rugosa Thunb.)为试验材料,探究野生玫瑰在果实形成过程中种子的发育及休眠性的形成和变化。选取青果期(1~35 d)、转色期(35~60 d)、红果期(60~75 d)的果实及种子,结合形态学、组织细胞学观察法及高效液相色谱技术,对果实各发育时期的种子形态、种胚及内果皮的发育进行研究,并分析种子内源激素含量变化与果实发育、种子休眠之间的关系。结果表明:果实和种子在青果期(1~35 d)时发育速度最快,种胚在花后24 d发育完全,种子不存在形态休眠。花后24 d内果皮开始沉积木质素并逐渐木质化,种子开始产生机械休眠。种子激素含量的变化与果实的发育、转色及内果皮的木质化密切相关,种子内源GA3和ABA含量在青果期(1~35 d)达到峰值,内源IAA含量在果实转色期(35~60 d)达到最大值,高浓度的ABA含量是种子尚未脱离果实时便已进入生理休眠的主要原因。     

肌间刺缺失对斑马鱼骨骼发育的影响

利用斑马鱼(Danio rerio)野生型与肌间刺完全缺失突变型个体, 从骨骼染色和骨骼发育相关基因表达两方面, 初步评价了肌间刺缺失对斑马鱼骨骼发育的影响。通过骨骼染色对比观察了两种肌间刺表型个体受精后8dpf(days post fertilization, dpf)到56dpf的骨骼发育情况, 结果显示, 两种肌间刺表型除肌间刺外, 其他骨骼发育基本同步。此外, 通过qRT-PCR实验检测分析了6个骨骼发育相关基因(bmp2a、bmp4、smad1、smad4a、runx2a和sp7)在不同肌间刺表型5个胚胎发育时期(3hpf囊胚期、6hpf原肠胚期、12hpf体节期、24hpf咽囊期和72hpf孵化期)和5个胚后生长阶段(15、30、45、60和75dpf)的表达情况。结果显示:在胚胎发育时期, 野生型和突变型个体中bmp2a、bmp4、smad1、smad4a基因和突变型个体中sp7基因的表达均呈现先升后降的变化趋势, 且在体节期达到最高表达水平;野生型和突变型个体中runx2a基因和野生型个体中sp7基因则表现为逐渐上升的趋势。6个基因在囊胚期和原肠胚期表达量无显著差异, bmp2a的表达水平在体节期、咽囊期和孵化期无显著差异, 野生型个体bmp4、smad1、smad4a、runx2a基因在体节期、咽囊期和孵化期的表达水平明显高于突变型, 而sp7基因则表现为突变型明显高于野生型。胚后发育阶段 6个基因在5个生长阶段均呈现逐渐下降的趋势, 且在两种肌间刺表型间其表达仅在个别时期差异显著。综上所述, 肌间刺的缺失对斑马鱼骨骼发育表现型无显著影响, 只在胚胎发育时期影响骨骼相关基因表达水平的变化;结合骨骼染色结果, 推测肌间刺缺失对斑马鱼骨骼发育无显著影响。     

滇黄精组培褐化影响因素研究

以滇黄精Polygonatum kingianum块茎芽为外植体,对组培过程中褐化的影响因素(灭菌方式、基本培养基及培养温度)进行探讨。结果表明,先经过75%乙醇处理30s消毒表面,再用NaClO 12min+HgCl2 8min消毒的抗褐化效果最好;选用1/2MS基本培养基能有效抑制褐化;低温环境(20℃)能进一步降低褐化发生率。     

季风进退和转换对中国褐飞虱迁飞的影响

利用近30年NCEP/NCAR 逐日气象再分析资料及中国褐飞虱逐候灯诱数据,分析季风指数与褐飞虱迁入量的时空关系,以探明季风进退和转换对我国褐飞虱迁入的影响。研究表明:(1)常年3月中、下旬是我国偏北季风转换为西南季风的时期,西南季风开始后的4月上旬是褐飞虱第1次大规模北迁的时期,第1次大规模北迁的主降区为华南稻区和西南稻区,随后迁向其北的其他稻区。(2)6月中旬-8月中旬是偏南季风指数达最大值的时期,也是各稻区褐飞虱北迁峰次最多、迁入量最集中的时期。(3)8月下旬至9月中旬为偏南季风向偏北季风的转换时期,也是褐飞虱北迁的终见期、南迁的始见期,第1次大规模南迁发生在这一时期内,主降区为江淮稻区和江岭稻区。(4)9月下旬至10月中旬是偏北季风的快速增强期、偏南季风的快速衰退期,也是褐飞虱南迁的高峰期。(5)10月下旬开始偏南季风撤出我国大陆,而偏北季风控制我国大陆,由北到南各稻区依次开始出现褐飞虱迁入的终见期。(6)褐飞虱异常发生年份中西南季风北上的早迟决定了褐飞虱在我国迁入始见期的早晚,而偏北季风南下的早迟则决定了我国褐飞虱迁入终见期的早晚。(7)迁入始见期滞后于西南季风的变化,迁入终见期滞后于偏北季风的变化,它们滞后的时间都为1-3候(即5-15d)。     

黑莓外植体褐化影响因素分析及适宜培养条件筛选

以黑莓(Rubus spp.)品种'Kiowa'为实验对象,研究了基本培养基类型、外植体类型、枝条暗处理时间、防褐化剂以及光照度对组织培养中外植体褐化及腋芽诱导的影响.结果表明,在供试的6种基本培养基(MS、1/2 MS、B5、1/2 B5、N6和1/2 N6)中,在MS培养基上外植体的褐化率较低(37.78%)、腋芽诱导率最高(67.89%)且生长状况良好;褐化程度与外植体的木质化程度及取材部位均有一定的关系,以1年生半木质化枝条的上部茎段为外植体,褐化率最低(19.67%)、腋芽诱导率较高(91.89%)且生长状况良好;接种前进行一定时间的暗处理对外植体褐化有一定的抑制作用,对枝条暗处理3 d,防褐化效果最佳;在培养基中添加不同类型和浓度的防褐化剂对外植体褐化和腋芽诱导也有一定的影响,以添加3 000 mg·L-1活性炭或200 mg·L-1 VC的防褐化效果较好;培养过程中的光照度与外植体褐化也有一定的关系,在1 500 lx光照度下外植体的褐化率较低(15.66%)且腋芽诱导率和生长状况均较好.根据实验结果,筛选出防止黑莓外植体褐化的适宜培养条件为:以1年生半木质化枝条的上部茎段为外植体,15 ℃暗处理3 d后,消毒并接种在添加了3 000 mg·L-1活性炭或200 mg·L-1 VC的MS培养基(含20 g·L-1蔗糖、5.6 g·L-1琼脂及0.2 mg·L-1 6-BA,pH 5.8)上,置于光照度1 500 lx的条件下培养.     

O2和CO2配比对气调贮藏梨采后褐变及相关理化因子的影响

以采后'丰水'梨果实为材料,在乐扣气调试验箱中研究了O2和CO2配比对果实褐变率、多酚氧化酶(PPO)和过氧化物酶(POD)活性、丙二醛(MDA)和总酚含量的影响,以探讨适宜减轻梨气藏褐变的气体成份.结果表明:在整个贮藏过程(150 d)中,'丰水'梨果肉未发生褐变.从贮藏60 d开始,气调处理和冷藏对照果实的果皮均出现褐变,气调处理在贮藏120 d之前对果皮褐变的影响不显著,而在贮藏120～150 d内可显著减轻果皮的褐变、抑制果皮PPO和POD活性及降低总酚含量.与冷藏对照相比,气调处理可推迟果心褐变的时间,且(8%～10%)O2+3% CO2处理可完全抑制果心的褐变;气调处理亦可降低果心PPO活性、减少总酚及MDA含量;(8%～10%)O2+1% CO2处理能够显著提高果心的POD活性,而(8%～10%)O2+3% CO2处理对果实POD活性的影响不显著.可见,气调贮藏主要是通过降低'丰水'梨果皮PPO、POD活性及总酚含量来减轻组织的褐变,并以(8%～10%)O2+3% CO2处理对果实褐变因子的控制效果较理想.     

新疆2个主栽早实核桃品种无融合生殖及胚细胞发育研究

以新疆‘新新2’、‘温185’2个主栽早实核桃品种为材料,通过对雌花采取套硫酸纸袋、聚乙烯醇封柱头、切柱头等3种无融合生殖处理,以自然授粉为对照,观察分析了无融合生殖胚乳和胚发育过程,结果显示:(1)‘新新2’的自然座果率比‘温185’要高,但其无融合生殖率却略低于‘温185’。(2)无融合生殖形成的果实较正常自然生长形成的果实略小。(3)2个核桃品种胚囊均属蓼型,历经10d左右发育成熟。(4)2个品种无融合生殖胚均由卵细胞分裂发育而来,经原胚期、球形期、心形期、鱼雷形期、成熟期发育完成,历经10d左右,属孤雌生殖类型。(5)2个核桃品种均属核型胚乳,8d左右形成胚乳细胞。     

毛竹种子形成过程中形态解剖学特征

为揭示毛竹(Phyllostachys edulis)种子生长过程中胚、胚乳、果皮及种皮的发育规律,以桂林海洋山一带的开花毛竹为材料,采集并固定不同时期的开花毛竹种子,使用石蜡制片法制片,显微镜观察胚、胚乳、果皮与种皮的结构变化。结果表明：(1)毛竹花后1 d完成受精并形成合子,合子休眠时长约为5 d。经过原胚阶段、胚芽鞘阶段、幼胚生长阶段及成熟胚阶段,花后40 d的胚发育基本成熟,其发育类型为禾本型。(2)胚乳发育早于胚的发育,其发育类型为核型胚乳,历经游离核、细胞化、细胞分化及成熟4个阶段。在细胞分化阶段胚乳细胞分化形成淀粉胚乳细胞以及糊粉层细胞,淀粉胚乳细胞主要积累淀粉粒,糊粉层细胞主要积累矿质元素、脂类及蛋白质等。(3)花后1 d的果皮细胞及珠被细胞形状规则、内含物丰富、结构完整;花后10～20 d,内、外果皮及珠被细胞层数递减,形状发生改变,中果皮细胞开始出现淀粉粒;花后20～60 d,随着胚乳细胞营养物质的积累及体积的增大,向外产生机械压力,中果皮细胞逐步消解仅剩残留的细胞壁;外果皮细胞呈长条形,细胞壁加厚,与残留的中果皮细胞壁组成保护结构;皮层在种子发育过程中主要起到合成...     

景宁木兰组织培养外植体选择与抗褐化研究

该研究以景宁木兰(Magnolia sinostellata)为材料,从外植体类型的选择、消毒时间、预处理方法、离体培养条件和抗褐化剂类型选择等方面进行综合研究,以期筛选出景宁木兰组织培养的最佳方案。结果表明:利用0.1%氯化汞(HgCl_2)浸泡处理14和8 min分别是景宁木兰叶片和带芽茎段、根部的最佳消毒时间;景宁木兰叶片及茎段的褐化率在暗培养7 d时,分别为60.00%和56.67%,14 d时显著升高,而根部则在暗培养14 d时褐化率最低(45%);利用1 g·L~(-1)聚乙烯吡咯烷酮(PVP)浸泡预处理景宁木兰外植体6 h可显著降低(P0.05)其褐化程度,处理后叶片、带芽茎段和根部的褐化率分别降至45.00%、28.33%和63.33%。不同的抗褐化剂均可减轻外植体的褐化程度,但针对不同外植体其效果不同。景宁木兰叶片最佳抗褐化剂为0.02 g·L~(-1)硝酸银(AgNO_3),可使其褐化率降低至16.67%,成活率为11.67%;带芽茎段和根部的最优抗褐化剂为2 g·L~(-1)柠檬酸(CA),褐化率分别降至30.00%和5.00%,成活率依次为50.00%和76.67%。综上所述,带芽茎段和根部抗褐化处理后褐化率较低且成活率较高,为景宁木兰组织培养最佳外植体。     

中华水韭叶舌和缘膜的发生及其发育进程研究

采用石蜡切片技术,以人工培养的中华水韭幼苗的最初几枚叶至成熟植株的叶为实验材料,连续解剖观察其叶舌和缘膜的发生、发育进程,并分析其发育进程与孢子囊和叶片的关系.结果显示:(1)中华水韭叶舌与叶片在其个体发育早期来自于同一原基,但叶舌最初的发育速度快于叶片.(2)中华水韭的苗龄达到15枚叶时开始有孢子囊发生,此时的叶舌下方有明显的缘膜结构.(3)当中华水韭的孢子体达到30枚叶片以上时,早期产生于植株外围的孢子囊已经发育成熟,可以清楚地区分出大、小孢子囊,其中在已经成熟的大孢子叶上,叶舌相对于孢子囊的长度变短,下唇萎缩,缘膜消失;成熟小孢子叶的叶舌比大孢子叶的叶舌长,上翻程度大,下唇萎缩程度不如大孢子叶明显,缘膜也退化消失.研究认为,缘膜是水韭系统发育早期的普遍结构,而演化后期一些地区的缘膜则显著退化甚至消失;对于系统发育初期的中华水韭,其叶舌与叶片的差异并不像现代水韭那么明显.     

皂荚提取物的杀螺活性

[目的]研究皂荚生物农药活性,开发利用皂荚资源,发展环境友好的绿色植物源农药。[方法]采用室内生测和田间试验研究皂荚壳乙醇提取物的杀螺活性。[结果]皂荚提取物对福寿螺有显著的毒杀活性,对幼螺和成螺72 h的LC₅₀分别为40.56、109.83 mg·L^-1。田间试验表明,皂荚提取物对福寿螺有较好的防效,施用40 g·m^-2的皂荚提取物处理7 d后卵块减少率为100.00%（成螺失去产卵的能力）,防效为（99.12±1.26）%。[结论]皂荚提取物对福寿螺较好的生物防治效果,是一种潜在的生物杀螺剂。     

贵州省野生皂荚种实表型性状多样性分析

为深入了解贵州省野生皂荚(Gleditsia sinensis)荚果表型性状的遗传多样性及其变异类型,为皂荚的遗传改良、种质鉴定、亲本选择以及品种培育奠定理论基础。该研究以贵州省7个野生皂荚群体70个个体为研究对象,采用方差分析、主成分分析、相关性分析及多性状综合评价等方法对皂荚群体的10个种实表型性状进行系统分析和综合评价。结果显示：(1)所测皂荚的表型性状差异在群体内均达到极显著水平(P＜0.01);在群体间,除每荚粒数、种子宽、种子长宽积以及种子长宽比之外,其余表型性状的差异均达极显著水平(P＜0.01)。(2)7个居群野生皂荚各性状平均变异系数为21.16%,其中凯里市(P4)居群的变异系数最高(24.44%);居群间荚果的变异(29.22%)高于种子的变异(11.04%),且变异主要来自于群体内。(3)相关分析显示,皂荚种实各性状之间存在不同程度的关联性;主成分分析显示,前4个主成分(皂荚种子大小、单个荚果出籽数量、种子形态指数因子、与荚果长和种子厚相关的因子)的累积贡献率达69.783%,可基本反映皂荚表型性状的大部分信息;以10个种实性状对皂荚野生群体进行综合评价发现,来自于惠水县(P7)群体的皂荚种实性状综合评价最高。研究表明,贵州省野生皂荚在群体间及群体内具有丰富的表型变异,且群体内的变异大于群体间的变异,变异主要来自于群体内。     

Xylem and Phloem Derived Polyamines during Flowering in Two Diverse Rose Species

Polyamine contents in xylem (root) and phloem (leaf) exudates in two diverse species of rose, viz. Rosa damascena Mill and Rosa bourboniana Desport, were analyzed before, during, and after flowering in the main flowering season, that is, April–May. Only free putrescine (Put) was detected in the xylem and phloem exudates at these time points, and it was high during the peak flowering period. In phloem, Put content was significantly higher in R. bourboniana than in R. damascena at all three stages; whereas in the xylem exudate it was relatively higher in R. damascena at the peak flowering period. A spray of α-difluoromethylornithine (DFMO), an irreversible inhibitor of the putrescine biosynthetic inhibitor ornithine decarboxylase (ODC), markedly decreased the flowering. This effect was reversed by application of Put alone or in combination with DFMO. The significance of this finding is discussed in light of polyamine translocation during flowering. *IHBT Communication: 0354     

皂荚种质资源SCoT遗传多样性分析及指纹图谱的构建

采用SCoT标记分析了18个皂荚种质的遗传多样性,并采用UPGMA法对18个皂荚种质进行了聚类分析。在此基础上,通过筛选出的多态性条带构建了18个皂荚种质的SCoT指纹图谱。扩增结果表明:从51个SCoT引物中筛选了15个引物进行PCR扩增,共扩增出226条带,其中多态性条带216条,多态性比率为96.61%。各引物多态性信息含量(PIC)、观测等位基因数(Na)、有效等位基因数(Ne)、Nei’s基因多样性指数(H)和Shannon’s信息指数(I)的平均值分别为0.875 9、1.964 9、1.440 1、0.272 6、0.426 1。18个皂荚种质的遗传相似系数在0.491 4~0.938 1之间,表明供试材料之间具有较丰富的遗传多样性。聚类分析结果表明:在遗传相似系数为0.60处可将18个皂荚种质分为3组,其中野皂荚单独为一组,山皂荚和皂荚-T聚为一组,其它皂荚材料聚为一组。利用3个引物扩增的8个多态性位点构建了18份皂荚种质资源的DNA指纹图谱,可以将其区分并精准鉴定。该研究结果为皂荚种质的鉴定和新品种选育提供了一定的理论依据。     

PETIOLE DEVELOPMENT AND XYLEM DIFFERENTIATION IN XANTHIUM REPRESENTED BY THE PLASTOCHRON INDEX

Petiole development and formation of xylem vessels have been investigated in Xanthium leaves from early ontogeny to maturity. Kinetics of growth was presented in terms of absolute and relative elemental rates of elongation. The process of vascularization was assessed by the number of differentiated xylem vessels. The leaf plastochron index (LPI) developed by Erickson and Michelini (1957) was used for designating the various stages of development. An exponential increase in petiole length was observed between the LPIs –3 and +4 indicating a constant relative rate of 0.20 or 20% increase per day. After cessation of lamina elongation at LPI 8, petiole elongation continued for an additional 5 day period, to LPI 9.5. Relative elemental rate analysis revealed that the basipetal pattern of elongation was maintained throughout the leaf development. At a specific plastochron age, the only growth was due to the petiole elongation. Leaves which ceased elongating had not completed their internal development, since the process of xylem formation continued for several plastochrons, or about 8 days. The highest rate of xylem formation was ten vessels per day at LPI 5. On the average, about five xylem vessels differentiated per day in the middle portion of a Xanthium petiole. Mature petioles contained an average of 218 xylem vessels. About 12 canals of schizogenous origin preceeded the development of the vascular tissue.     

Isolation and identification of substances inducing formation of tracheary elements in cultured carrot-root slices

Data are presented on the cytokinin status of seeds and seed components, at different stages of development in Phaseolus coccineus L., as determined with the soybean callus growth bioassay: A change in cytokinin types according to developmental stage occurred: from biologically very active less polar types (zeatin=Z) at early stages to more polar types (zeatin glucoside=Z₉G and zeatin riboside=Zr), with relatively low biological activity, at intermediate and late stages of seed development: When cytokinins were analyzed separately in embryos (embryo proper) and suspensors at two embryonic stages: heart-shaped (A) and middle cotyledonary embryos (stage B) respectively, it was found that: i) at stage A, the suspensor showed cytokinin activity at the level of Z, 2iPA (2-isopentenyladenosine) and Zr, whereas more polar cytokinins (Z₉G, Zr) were present in the embryo; ii) at stage B, when the embryo seems to become autonomous for cytokinin supply, there was a relative abundance of active cytokinins (Z, 2iPA) in the embryo to which Z₉G activity in the suspensor corresponded. It is concluded that the suspensor plays an essential role in embryogenesis by acting as a hormone source to the early embryo.Abbreviations GA gibberellic acid - 2iPA 2-isopentenyladenosine - Stage A heart-shaped embryo - siage B middle cotyledonary embryo - Z zeatin - Z₉G zeatin glucoside - Zr Zeatin riboside     

Mercury accumulation in five species of freshwater fish in Lake Tyrifjorden,south-east Norway,with emphasis on their suitability as test organisms

Synopsis Mercury concentration in axial muscle of brown trout, Salmo trutta, whitefish, Coregonus lavaretus, Arctic charr, Salvelinus alpinus, smelt, Osmerus eperlanus and pike, Esox lucius, were studied in Lake Tyrifjorden during 1978–1982. Our data demonstrate that older and bigger fish on an average have higher mercury concentration than smaller and younger. Further, complex life histories as in brown trout influence the pattern of mercury accumulation. During young stages accumulation in brown trout is moderate, while accumulation in older stages is highly correlated to lake residency time. Based on our data we suggest the following requirements for a test organism and the collecting procedure; (1) life history should be simple with small sexual differences, (2) ageing should be easy and reliable, and (3) large representative samples should be easily obtained during (4) a fixed biological period i.e. the spawning period. We consider smelt as an appropriate test organism based on these criteria.     

The larval development of an Australian limnadiid clam shrimp (Crustacea, Branchiopoda, Spinicaudata), and a comparison with other Limnadiidae

The adult morphology of the Australian Limnadopsis shows some remarkable differences to that of other Limnadiidae. These differences are not reflected in its larval development. In Limnadopsis parvispinus, larval development comprises six stages. In stages I and II only the three naupliar appendages are present: the antennule as a small bud, the biramous antenna as the main swimming organ, and the mandible. The antennal protopod bears two endites, the proximal naupliar process and a more distal endite. In stage III a bifid naupliar process (in earlier stages not bifid) and the first signs of the carapace and trunk limb anlagen (undifferentiated rudiments) appear. In stage IV the carapace anlagen become more pronounced. The number of trunk limb anlagens increases to five, and differentiation has commenced. In stage V the first five pairs of trunk limbs are differentiated to varying degrees. The anterior-most four pairs of trunk limbs are subdivided into five endites, a small endopod, an exopod and an epipod. The bivalved carapace covers the anterior-most limbs. In larval stage VI the carapace is larger and the trunk limbs are further differentiated. A general pattern in the sequence of larval stages is the increasing number of sensilla on the antennules. From the last larval to the first postlarval stage, a significant change in morphology takes place. The trunk limbs are now used for swimming. Typical larval organs are much smaller than in the last larval stage. A comparison with other representatives of the Limnadiidae shows a high degree of correspondence, with most differences explained by the heterochronous appearance of characters during development. Five to seven stages are described for all studied Limnadiidae, including one particular stage in which four fully developed setae, a bifid naupliar process and the first signs of carapace anlagen are present. These characters are found in stage III in L. parvispinus, Limnadia stanleyana, Eulimnadia texana, and Imnadia yeyetta but in stage IV in E. braueriana and L. lenticularis. Based on a comparison of the larval stages of six limnadiid and one cyzicid species, we conclude that at least six naupliar stages belong to the limnadiid ground pattern.