光强和光质对底栖藻类群落影响Ⅱ.群落和种群的动态和适应模式

将原始河口底栖藻类群落移植至实验室进行培养.底栖藻类群落分别由占细胞总量93.33%的硅藻类群、5.42%的绿藻类群和仅占1.25%的单一蓝藻种群组成.通过对底栖藻类群落总体、不同藻类类群和单一种群在不同光照强度的白光和单色光下的适应模式和增长动态的研究发现,底栖藻类群落总体增长动态为弱光适应型、红光敏感型和蓝光抑制型,其细胞生长的敏感光照依次为红光＞低光强＞中光强＞高光强＞绿光＞蓝光.底栖藻类群落总体对不同光照的适应模式由底栖硅藻类群增长动态所决定.底栖绿藻类群总体增长的敏感光照依次为低光强＞红光＞中光强＞绿光＞高光强＞蓝光,绿藻类群在不同的光照处理下呈现3种适应模式.硅藻类群总体对不同光照的敏感状况与底栖藻类群落总体趋同,在不同光照处理下仅呈现一种适应模式.蓝藻Oscillatoria tenuis种群的增长的敏感光照为红光＞白光＞绿光＞蓝光,其对光的适应模式有3种.7种绿藻种群在不同光强的白光、红光和绿光表现出2种适应模式,在蓝光下基本皆呈衰退型.21种硅藻种群对不同光照的适应模式可分为4种类型,强竞争型、弱竞争型、增长型和衰退型.     

不同强度的红光和蓝光下菜豆叶片的荧光特性

光质和光强均是影响植物光合作用的重要外部因素,该文以菜豆(Phaseolus vulgaris)为材料,通过叶绿素荧光技术比较研究了菜豆叶片在不同光强的红光和蓝光下叶绿素荧光特性的变化规律。结果表明:随着红光和蓝光光强的增加,菜豆叶片的光适应下的最大光化学效率(Fv'/Fm')呈下降趋势,但与在红光下相比,蓝光下叶片的Fv'/Fm'值较高。随着蓝光光强的增加,菜豆叶片PSⅡ实际光化学效率(Y(Ⅱ))和光化学猝灭系数(q P和q L)先呈上升趋势之后逐渐趋于平稳;而随着红光光强的增加,以上参数呈下降趋势。随着红光和蓝光光强的增加,非光化学猝灭系数(NPQ)、相对电子传递速率(ETR)以及调节性能量耗散的量子产量Y(NPQ)均呈上升趋势,但与在红光下相比,蓝光下叶片NPQ和Y(NPQ)的值较低,而ETR值较高。非调节性能量耗散产量Y(NO)随着红光光强增加而呈上升趋势,而随着蓝光光强增加呈下降趋势。综上可见,随着光强的增加菜豆叶片的光化学效率呈降低趋势,但叶片在蓝光下的光化学吸收和利用效率高于红光。研究结果可为植物对光强和光质的响应提供一定的参考。     

新型光源LED辐射的不同光质配比光对菊花组培苗生长的影响

采用新型光源LED辐射的红光[R,(658±20)nm]、远红光[Fr.(715±20)nm]和蓝光[B,(460±20)nm],观测不同红光/远红光(R/Fr)和红光/蓝光(R/B)配比光对菊花组培苗生长的影响.试验结果表明:红光处理的植株最高,根较长.远红光和蓝光处理的植株矮小,根短细.类胡萝卜素含量与R/Fr比率呈负相关,叶绿素a、叶绿素b、叶绿素(a b)、类胡萝卜素含量与R/B比率也呈负相关.叶绿素a/b比值与R/Fr和R/B比率呈正相关.红光有利于可溶性糖和淀粉的积累,降低色素含量.而蓝光能够逆转此效应,可促进色素和可溶性蛋白的合成.红光和蓝光组合处理的叶中可溶性糖和淀粉含量以及根系活力均高于白光处理的,尤以高R/B配比光处理的组培苗生长健壮,移栽成活率最高.     

光质对五种不同生活型植物的器官发生和生长的影响

本实验对百合、虎头兰、非洲紫罗兰、斑叶海棠和烟草五种不同生活型材料在离体培养诱导器官发生过程中,对光质及黑暗条件的反应进行了研究。结果指出,作为地下芽的百合和虎头兰小鳞茎、原球茎的发生不依赖于光质条件,而作为地面芽和地上芽的非洲紫罗兰与斑叶海棠的不定芽发生,在1.40mw/cm~2的光强下,红光有促进作用,蓝光和黑暗却有抑制作用;烟草则是蓝光对其不定芽的发生有利,而红光和黑暗有抑制作用。     

光质对马铃薯试管薯形成的影响

以两个试管薯形成能力不同的马铃薯脱毒试管苗为材料,研究不同光质(白光、红光、蓝光)对马铃薯试管苗生长和试管薯形成的影响.结果表明：红光下试管苗叶片的净光合速率、可溶性糖含量和生物量最高,试管苗叶片数多.蓝光对试管苗干物质含量和试管苗发育后期的结薯数量以及结薯期提前有明显促进作用,但对试管苗株高有明显抑制作用.白光下试管苗净光合速率和干物质含量最低.不同品种试管薯的形成对光质的要求有一定差异.总之,壮苗培养阶段采用红光,试管薯诱导阶段采用蓝光处理利于提高试管薯产量.     

不同LED光源对乌塌菜生长、光合特性及营养品质的影响

与传统光源相比,LED具有光谱可控、亮度高但发热量小、寿命长等优势.LED光源可实现光谱可控,通过调制光谱与植物的感光细胞最优结合来影响植物的生长发育与营养品质.本研究利用LED精量调制光源,以‘菊花小八叶’乌塌菜品种为试验材料,设红光、蓝光、红/蓝光(3/1)、红/蓝光(7/1)、白/红/蓝光(3/2/1)5个处理,以白光为对照,研究不同光质对乌塌菜生长、光合特性及品质的影响.结果表明： 红光有利于乌塌菜生物量和茎粗的增大,而蓝光有抑制作用;叶绿素含量以红/蓝光(7/1)处理最高,且叶绿素总量与红/蓝光比值呈正相关,虽然蓝光显著降低叶绿素含量,但提高了叶绿素 a/b 值;光合速率和蒸腾速率均以红光处理最高,与对照相比分别增加43.8%和55.1%,而蓝光处理下有较高的气孔导度及胞间CO₂浓度.不同光质处理对乌塌菜的荧光参数有较大影响,白光的F_v/F_m、F_v/F_o和Φ_PSⅡ均最大;红光可以提高可溶性糖含量,蓝光能提高可溶性蛋白含量,白光能增加维生素C含量.综合分析,红/蓝光(7/1)处理在增加叶片光合色素含量,提高光合速率,促进植株生长和改善营养品质方面为最优组合.     

不同光质补光对促早栽培‘瑞都香玉’葡萄果实品质的影响

以4年生‘贝达’嫁接的早熟葡萄品种‘瑞都香玉’为试材,研究设施促早栽培条件下,紫外光、蓝光和红蓝光不同光质补光对果实品质的影响,结果表明: 促早栽培节能日光温室内环境属于典型的弱蓝紫光和弱紫外光环境.与对照(未补光)相比,夜间6 h的蓝光和紫外光补光处理可显著加快葡萄果实发育过程中质量和果粒纵横径的增大、果实糖含量的升高以及酸含量的下降,红蓝光效果不明显.果实成熟期紫外光补光处理果实的单粒质量最高,蓝光与红蓝光处理显著高于对照;蓝光补光处理果实葡萄糖、果糖和总糖含量最高,紫外光次之,红蓝光略高于对照.与对照相比,蓝光补光处理可显著加快果实中里那醇、α-萜品醇、橙花醇等萜烯类组分含量高峰的出现,而紫外光、红蓝光补光处理差异较小.果实成熟期蓝光补光处理果实中里那醇、香茅醇等萜烯类物质含量最高,紫外光补光处理里那醇含量较高,香叶醇、己醛、E-2-己烯醛等主要香气物质的含量最高,而红蓝光补光处理里那醇的含量与对照相比有所降低.紫外光、蓝光和红蓝光3种光质补光处理均增加了果实中醛酮类物质的种类及含量.表明蓝光补光处理果实发育最快,成熟最早,糖含量最高,里那醇等萜烯类物质含量高峰出现的时间最早;紫外光补光处理果实的单粒质量最大,主要萜烯类组分含量高;红蓝光补光处理对改善果实品质的效果不明显.     

单色光对小麦草生长速率的影响研究

通过LED光照实验,探究不同光质和光周期对小麦草生长速率的影响。采用大功率红、蓝LED灯,红光峰值波长为655 nm,蓝光峰值波长为438 nm。实验采用控制变量法,以光质和光周期为变量,其余生长环境保持一致。结果表明:红光照射下生长速率要明显优于蓝光,甚至超过室内日光。在红蓝复合光中,红光光强高于蓝光时,更利于小麦草生长;连续24 h的光照与间隔12 h的光照相比,略有生长优势。     

光信号对AmRosea1过表达84K杨花青素合成及基因表达的影响

为了探究光信号引起AmRosea1过表达84K杨(Populus alba×P.glandulosa ‘84K’)植株颜色变化的原因,以野生型和AmRosea1过表达84K杨为试验材料,开展LED光、自然光、LED红光、LED蓝光和LED红蓝光处理,测定不同光强和光质下野生型和转基因株系的生理指标变化情况。结果显示：在不同光强下,与LED光处理相比,自然光处理下转基因株系叶片变红,花青素和可溶性糖含量升高,叶绿素含量和POD活性降低。不同光质处理30 d后,与LED红光和蓝光相比,在LED红蓝光诱导下,转基因株系叶片变红,且花青素含量升高,可溶性糖含量和POD活性下降,叶绿素含量略有降低。根据试验结果推测,强光和红蓝光质能激活AmRosea1过表达84K杨的花青素生物合成通路,使转基因株系积累大量的花青素,从而使植株叶片变红。     

LED光质对茄子果实品质及抗氧化能力的影响

采用发光二极管(LED)精量调制光质和光强,以白光为对照,研究红光、蓝光和红蓝组合光对‘布利塔’长茄果实品质、抗氧化能力及产量的影响.结果表明: 蓝光处理下,茄子果肉中可溶性蛋白、游离氨基酸和茄皮中花青素含量显著高于其他处理,分别比对照高15.1%、27.2%和73.6%,但果肉中类黄酮、总酚含量及产量显著低于其他处理;红光处理下,茄皮中类黄酮含量显著高于其他处理,但果肉中维生素C(Vc)和可溶性蛋白含量显著低于其他处理;红蓝组合光处理下,果肉中可溶性糖及茄皮中总酚、红色素、黄色素含量、总抗氧化能力以及产量均显著高于其他处理,其中茄皮中总抗氧化能力及产量分别比对照高43.5%和43.4%;而白光处理下,果肉中Vc、类黄酮和总酚含量及总抗氧化能力最高.茄皮中总酚及果肉中Vc含量与其总抗氧化能力呈显著正相关.设施栽培条件下,适当补充蓝光或红光均有利于改善茄子部分品质,红蓝组合光更有利于改善茄皮品质与产量形成.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.