退化高寒草甸关键生态属性对多途径恢复措施的响应特征

高寒草甸是青藏高原的主体植被类型，但退化态势较为严峻，严重威胁青藏高原生态屏障的战略地位。退化高寒草甸的复健是世界性难题，治理效果也因退化状态、恢复措施及气候环境而异。以春季休牧、秋季休牧、畜群结构优化、减畜轮牧、围栏封育及翻耕改建等典型多途径恢复措施下的退化高寒草甸为对象，系统探讨主要生态要素和生态功能的响应特征及潜在过程。结果表明，典型恢复措施下退化高寒草甸的植被生产力、土壤有机碳密度及土壤饱和持水量等生态要素都得到一定程度的提升，而恢复效果与实施年限及恢复措施密切相关。围栏封育和翻耕改建下土壤有机碳密度及饱和持水量随恢复年限均表现为对数饱和型的响应特征，退化高寒草甸固碳持水功能的基本恢复年限约为6—10年。春季休牧、秋季休牧、畜群结构优化、减畜轮牧、围栏封育等放牧管理恢复措施应适用于轻度退化至重度退化的高寒草甸，而翻耕改建则是极度退化高寒草甸的适宜治理措施。由于多途径恢复措施的关注目标不同，今后研究应集中在恢复措施的组合优化和综合评价等方面。     

A New Glabrous Gene (csgl3) Identified in Trichome Development in Cucumber (Cucumis sativus L.)

Spines or trichomes on the fruit of cucumbers enhance their commercial value in China. In addition, glabrous mutants exhibit resistance to aphids and therefore their use by growers can reduce pesticide residues. Previous studies have reported two glabrous mutant plants containing the genes, csgl1 and csgl2. In the present study, a new glabrous mutant, NCG157, was identified showing a gene interaction effect with csgl1 and csgl2. This mutant showed the glabrous character on stems, leaves, tendrils, receptacles and ovaries, and there were no spines or tumors on the fruit surface. Inheritance analysis showed that a single recessive gene, named csgl3, determined the glabrous trait. An F₂ population derived from the cross of two inbred lines 9930 (a fresh market type from Northern China that exhibits trichomes) and NCG157 (an American processing type with glabrous surfaces) was used for genetic mapping of the csgl3 gene. By combining bulked segregant analysis (BAS) with molecular markers, 18 markers, including two simple sequence repeats (SSR), nine insertion deletions (InDel) and seven derived cleaved amplified polymorphism sequences (dCAPs), were identified to link to the csgl3 gene. All of the linked markers were used as anchor loci to locate the csgl3 gene on cucumber chromosome 6. The csgl3 gene was mapped between the dCAPs markers dCAPs-21 and dCAPs-19, at genetic distances of 0.05 cM and 0.15 cM, respectively. The physical distance of this region was 19.6 kb. Three markers, InDel-19, dCAPs-2 and dCAPs-11, co-segregated with csgl3. There were two candidate genes in the region, Csa6M514860 and Csa6M514870. Quantitative real-time PCR showed that the expression of Csa6M514870 was higher in the tissues of 9930 than that of NCG157, and this was consistent with their phenotypic characters. Csa6M514870 is therefore postulated to be the candidate gene for the development of trichomes in cucumber. This study will facilitate marker-assisted selection (MAS) of the smooth plant trait in cucumber breeding and provide for future cloning of csgl3.     

Studies on the regeneration-restore and karyotype of protoplast in Metarhizium anisopliae var. majus

Abstract:  The characteristics and regeneration-restore of protoplasts and its karyotype of an insect pathological fungus, Metarhizium anisopliae var. majus were studied. Among the protoplasts, 25.3% were without a nucleus, and 74.7% contained a nucleus. Among the nucleus protoplasts, 53.6% contained a single nucleus. The regeneration-restore of protoplasts was of three distinct shapes. Considering the frequency of regeneration and the growing speed of the colony, 0.7 mol/l glucose was the optimum as osmotic stabilizer of culture medium in the regeneration-restore of the protoplasts. The chromosomal DNA molecules of M. anisopliae var. majus have been separated into seven bands by pulsed-field gel electrophoreses. Using the Schizosaccharomyces pombe chromosomes as size standard, the size of chromosomal DNA was estimated to be 1.1–6.5 Mb and its karyotype exhibited polytypism among strains.     

感染环形泰勒焦虫(Theileria annulata)的牛外周血白细胞的形态观察

用光镜及扫描电镜观察了体外高代培养的含牛焦虫颗粒的牛外周血白细胞的形态及在细胞周期中细胞表面的特征性变化。这种经多年传代的含虫的牛外周血白细胞恢复了分裂和繁殖的能力,目前已成为较稳定的细胞系。细胞表面具多种伪足突起,如叶状、丝状及绒毛状。细胞周期中备期细胞表面的主要特征是:S期:细胞平扁,边缘具薄的时状伪足及丝状伪足;G_2期:细胞中部隆起,表面具少量绒毛状伪足;G_1期:绒毛状结构少或无,而出现丝状及小的叶状伪足,细胞仍保持球形;M期:细胞球形,表面密被以绒毛。作者根据扫描电镜的观察认为光镜下所观察的两类细胞,实际上是反映了一种细胞处于不同发育阶段时的特征。     

四川大头茶净光合作用生理生态的初步研究

为了探讨重要生理生态因子在自然条件下对四川大头茶净光合作用(p_n)的影响,本文采用改良半叶法测定净光合作用的日变化和年变化。结果表明:春夏秋三季晴天p_n日变化呈双峰曲线型,即上,下午各出现一次P_n高峰,蜂谷则是P_n中午降低现象。冬季晴天P_n呈单峰曲线型。5月至11月P_n平均值为9.00mg·dm~(-2)·h~(-1)最高值23.44mg·dm~(-2)·h~(-1)出现在8月底。 一定程度上,P_n年变化曲线与温度年变化曲线相似,可以明显地区分为三部分。第一部分是从1月至5月,P_n随着温度的逐步上升而逐步升高。5月至10月为第二部分,此间P_n波动较大。10月至12月为第三部分,P_n随着逐步下降的温度而逐步降低。P_n季节变化显著,与植物生长、发育节奏相关。 温度和光照强度是影响P_n最重要的生态因子,相对湿度,叶绿素含量和SLW对P_n影响不大。温度与P_n呈一不对称钟形曲线,P_n的最低温度是4—5℃,最适温度是25—30℃,或稍高于30℃,最高温度则大于30℃。P_n的光饱和点在70,000lx左右,光补偿点约为3,000lx.在最适温度(25—30℃)范围内,P_n主要由光强所控制,并与光强呈正相关,一旦低于或超过最适温度,P_n则主要由温度所决定,与温度呈正相关。 遮阴实验表明,四川大头茶是具相当耐阴能力的阳性植物。     

下丘脑外侧区注射TRH对大鼠胃酸分泌的影响

本文采用连续收集胃腔灌流法,观察下丘脑外侧区(LHA)注射促甲状腺激素释放激素(TRH)对大鼠胃酸分泌的影响,并分析TRH在LHA促进胃酸分泌的作用机制。结果表明:(1)LHA注射TRH(1μg)明显地刺激胃酸分泌;(2)预先向LHA注射酚妥拉明(10μg)、美多心安(5μg)及胃泌素抗体1μl(1:640)并不影响TRH的泌酸作用,如预先向LHA注射阿托品(5μg)则可消除TRH的泌酸效应;(3)垂体摘除及肾上腺切除均不影响TRH的泌酸作用;(4)隔下迷走神经切断后,LHA注入TRH的泌酸效应仍然出现,但持续时间显著缩短;腹腔交感神经节摘除后,TRH仍能促进胃酸分泌,但分泌量少而平稳。以上结果提示:LHA是TRH中枢泌酸效应的有关结构之一,其中枢机制是通过胆碱能M受体中介的,腹腔交感神经节和膈下迷走神经是TRH泌酸效应的传出途径。前者引起的泌酸反应出现较早且引起泌酸高峰,但持续时间短;后者则引起低平的持续分泌。     

电刺激兔脑干中缝背核引起呼吸易化效应的观察

本文在30只全麻、制动、断双侧迷走神经的家兔上,记录一侧膈神经放电,观察了电刺激脑干中缝背核(Nucleus Raphe Dorsalis,NRD)所诱发出的呼吸效应。1.施以6—10s 长串电脉冲刺激(波宽0.3ms,频率100Hz,波幅4—6V),诱发出了强的呼吸易化效应,使呼吸加深加快。2.吸气相给予0.4s 短串电脉冲刺激可以明显的延长吸气相,用0.15mA 强度刺激,落位在吸气相的2/3时效应最明显。3.呼气相短串电脉串刺激可规律地使呼气时程缩短,促进呼气向吸气的位相转换,诱发此效应出现的强度阈值在呼气相中逐渐降低。