Comparative studies on histological and ultra-structure of the pituitary of different ploidy level fishes

The histological and ultra-structure of the pituitary in diploid red crucian carp(Carassius auratus red var.),triploid crucian carp and allotetraploid hybrids within and after the breeding season were comparatively studied.The result showed that there were six endocrine cell types in the pituitary of these three kinds of fishes,and there was an obvious difference in cell size among different ploidy level fishes.As for the same type of pituitary cells,the cell size was increased gradually with the in- creasing ploidy level.In the breeding season,the allotetraploid hybrids had higher proportion of go- nadotropin cells(GTH)than triploids,and the triploids had higher proportion of GTH than diploids.The results were related to the earlier sexual maturity of allotetraploid hybrids and sterility of triploid cru- cian carp.On the other hand,among the three kinds of fishes,the proportion of somatotropin(STH) cells in triploids crucian carp was the highest,whereas that in allotetraploid hybrids was the lowest. The results might be connected with the faster growth rate of triploids and slower growth rate of al- lotetraploid hybrids.In addition,in GTH cells of meso-adenohypophysis after the breeding season, there were many endocrine particles in triploids,while those endocrine particles were released from the cells in allotetraploids and diploids.This result showed that the sterility of triploid crucian carp might be related to the hormone which was not released from the GTH cells.In a word,the present study indicated that the differences in the structure of pituitary among different ploidy level fishes contributed to their difference in the growth rate and gonadal development.     

盐胁迫对扁桃光合特性和叶绿体超微结构的影响

温室条件下,分别用浓度为150、300、350 mmol/L的NaCl和Na2SO4处理‘石头扁桃’和‘桃扁桃’实生苗植株,处理10 d后分别测定其叶片叶绿素含量、净光合速率、气孔导度、细胞间隙CO2浓度,并观察叶绿体超微结构的变化。研究发现:(1)盐胁迫下,‘石头扁桃’和‘桃扁桃’chl a、chl b均在低浓度盐区含量最高,而在高浓度盐区含量最低,Na2SO4处理区chl a、chl b含量均低于NaCl处理区;(2)‘石头扁桃’和‘桃扁桃’叶片净光合速率随盐浓度的增加而下降,‘石头扁桃’下降的幅度较大;(3)‘桃扁桃’叶片细胞间隙CO2浓度随盐浓度的增加而升高,但‘石头扁桃’叶片细胞间隙的CO2浓度变化没有稳定的规律;(4)2个品种的叶片气孔导度均随盐浓度的增加而降低;(5)盐胁迫后,叶绿体基粒、基质片层扭曲,类囊体肿胀;随盐浓度的增加,形变加剧,叶绿体由椭圆形肿胀成圆形,叶绿体膜解体,且‘石头扁桃’叶绿体对盐胁迫比较敏感。综合分析发现,2种盐胁迫对植物造成伤害的机理不同,‘石头扁桃’的耐盐能力较差。     

枸杞花粉发育的超微结构变化

用JEM-100CXⅡ透射电子显微镜对宁夏枸杞(Ly cium barbarum L.)花粉发育过程做了超微结构观察.结果表明,在花粉母细胞细线和偶线期,核糖体数量减少、线粒体结构简化;之后核糖体数量逐渐回升,后期Ⅰ线粒体结构恢复正常.小孢子液泡化过程中核糖体再次减少,同时线粒体和质体结构简化;在早期二胞花粉中,核糖体数量增加、线粒体和质体结构再度分化.花粉母细胞和小孢子发育过程中都存在“细胞质改组”现象,且这两次“细胞质改组”与细胞功能的转变密切相关.在次生造孢细胞、花粉母细胞和小孢子后期都有液泡数量明显增加或体积增大的过程.前两次液泡的增加可能参与了其胼胝质壁的构建;而小孢子晚期中的大液泡则创造了一种极性为其不等分裂作好了生理和结构上的准备.     

螺旋粉虱成虫触角的感器

应用环境扫描电镜(ESEM)对螺旋粉虱Aleurodicus dispersus Russell雌雄成虫触角感器的外部形态结构数量和分布进行观察。结果表明螺旋粉虱成虫触角存在着以下5种感器,即毛形感器、板状感器、腔锥感器、刚毛形感器和锥形感器。腔锥感器仅在雌成虫触角中发现。雌、雄虫的板状感器和锥形感器数量差异不显著。本文试图确定螺旋粉虱成虫触角感器的功能,以了解该粉虱寄主选择行为的嗅觉基础。     

Relationship between photoinhibition of photosynthesis, D1 protein turnover and chloroplast structure: effects of protein synthesis inhibitors

Irradiation of Spinach oleracea intact leaf tissue and of mesophyll protoplasts of Valerianella locusta at 20° C with strong light resulted in severe (40–80%) inhibition of photosynthesis, measured as photosystem II electron transport activity in isolated thylakoids or as fluorescence parameter F_V/F_M on intact leaf disks. No net degradation of the D1 protein of photosystem II was seen under these conditions. However, in the presence of streptomycin, an inhibitor of chloroplast protein synthesis, net D1 degradation (up to about 80%) did occur with a half-time of 4–6h, and photoinhibition was enhanced. Thylakoid ultrastructure remained stable during photoinhibition, even when substantial degradation of D1 took place in the presence of streptomycin. When leaf disks were irradiated at 2°C, streptomycin did not influence the degree of photoinhibition, and net Dl degradation did not occur. These results suggest that in excess (photoinhibitory) light at 20°C, turnover (coordinated degradation and synthesis) of D1 diminished the degree of photoinhibition. The observed photoinhibition is thought to be due to the accumulation of inactive photosystem II reaction centres still containing D1. In the presence of streptomycin, the Dl protein was degraded (probably in the previously inactivated centres), but restoration of active centres via D1 synthesis was blocked, leading to more severe photoinhibition. Low temperature (2°C), by restricting both degradation and resynthesis of D1, favoured the accumulation of inactive centres. Streptomycin and chloramphenicol (another inhibitor of chloroplast protein synthesis) were tested for side-effects on photosynthesis. Strong inhibitory effects of chloramphenicol, but much less severe effects of streptomycin were observed.     

黑肩绿盲蝽外生殖器及其感器的超微结构

黑肩绿盲蝽Cyrtorhinus lividipennis Reuter是稻飞虱重要天敌之一.为分析黑肩绿盲蝽成虫生殖器上与生殖有关的感器类型,本文通过扫描电镜对黑肩绿盲蝽雌成虫交配孔和产卵器,雄成虫交配器感器分布进行了观察.结果表明,黑肩绿盲蝽雌成虫交配孔有毛形感器Ⅱ(TSⅡ)和锥形感器Ⅱ(BSⅡ)2种感器;产卵器上有毛形感器Ⅰ(TS Ⅰ)、刺形感器(CHS)、凹状感器(DS)、锥形感器Ⅰ(BS Ⅰ)等4种感器;雄成虫交配器上有毛形感器Ⅰ(TS Ⅰ)、二叉状感器(DIS)、刺形感器(CHS)、凹状感器(DS)、钟形感器(CAS)、栓锥形感器Ⅰ(SS Ⅰ)、栓锥形感器Ⅱ(SSⅡ)和腔形感器(CS)等8种感器.研究结果为揭示黑肩绿盲蝽外生殖器上感器在其交配和产卵过程中的作用奠定了基础.     

Comparative Proteomic Analysis of Rice Shoots Exposed to High Arsenate

Consumption of arsenic contaminated water and cereals is a serious threat to humans all over the world. Rice (Oryza sativa“Nipponbare”), as a main cereal crop, can accumulate arsenic more than 10-fold ...     

GB对低温胁迫黄瓜叶绿体及SOD、POD同工酶的影响

采用电镜观察和聚丙烯酰胺垂直板电泳法,研究了GB对低温胁迫下黄瓜幼苗叶绿体超微结构和SOD、POD同工酶的影响。结果表明,低温胁迫下,GB可使黄瓜幼苗叶绿体膜结构保持完好,而对照的叶绿体基粒破坏严重;与对照相比,GB处理对SOD、POD同工酶谱带数目均无影响,但POD同工酶的P2(Rf0．24)、P3(Rf0．30)、P4(Rf0．36)酶带的活性增加,SOD同工酶的S1(Rf0．14)、S5(Rf0．58)酶带活性较高,保持了黄瓜幼苗体内相对较高的抗氧化酶活性。GB可保护膜的完整性和稳定性,从而提高黄瓜幼苗的抗冷性。     

INDIAN OCEAN NANOPLANKTON. I. RHABDOSPHAERACEAE (PRYMNESIOPHYCEAE) WITH A REVIEW OF EXTANT TAXA1

Family characteristics of the Rhabdosphaeraceae are revised to limit the genera to those having cyrtoliths; genera with placoliths are removed from the family. Rhabdoliths, cyrtoliths bearing a process in the central area, are present in all genera. Coccospheres having monomorphic coccoliths, all being rhabdoliths, form one group within the family, whereas genera with dimorphic coccoliths in the coccosphere comprise a second group. Cyrtoliths without processes in the latter group may be intermixed with rhabdoliths in some genera, whereas other genera have rhabdoliths located only in polar regions of the coccosphere. Two generic nomenclatural changes are proposed, Algirosphaera being the name applied to species previously placed in Anthosphaera, an invalid generic name, and Palusphaera is recognized as a valid monotypic genus, P. vandeli being the name applied to the species that has been named Rhabdosphaera longistylis in recent literature. A new combination is made, Rhabdosphaera xiphos (Deflandre et Fert) comb. nov., recognizing a species formerly known only in sediments as extant. Rhabdosphaera, Acanthoica and Algirosphaera are genera with dimorphic coccoliths in the coccospheres; Discosphaera, Palusphaera and Anacanthoica are genera having monomorphic coccoliths in the coccosphere.     

Cold storage of in vitro cultures of hybrid poplar shoots (Populus alba L. x P. grandidentata Michx.)

Shoot cultures of P. alba x P. grandidentata Crandon were maintained for more than 5 years at 4°C with minimal growth. The highest survival after 2 years and 5 years of cold storage were 70% and 25% respectively using 1-month of pre-storage culture on MS medium containing 1.33 M BA. When 5-year-old cold-stored shoot cultures were transferred to the greenhouse, color variations were observed. The frequencies of albino and red pigmented plants were 0.25% and 12.8%, respectively. A rosette type growth pattern was also observed on 0.3% of the long-term cold-stored plants. During long-term cold storage there were local disruption of cambium connections and the accumulations of chemicals in some cells, as observed by light microscopy.