盐胁迫对中国柽柳幼苗生理特性的影响

以中国柽柳(Tamarix chinensis Lour.)插穗为研究材料,在装有不同土壤盐分梯度(0.4%、0.8%、1.2%、1.6%、2.0%、2.4%)的盆钵中进行扦插试验,测定柽柳扦插成活率、叶绿素含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性及丙二醛(MDA)含量等指标,研究分析柽柳扦插成活率及幼苗生理特性对盐分胁迫的响应特征。结果表明:(1)柽柳扦插成活率随盐胁迫增强逐渐降低,适合扦插繁殖的土壤含盐量低于0.8%;土壤含盐量超过0.8%后,扦插成活率太低,不适合柽柳进行扦插繁殖。(2)柽柳可通过提高叶绿素含量来适应盐胁迫,随着盐胁迫增强,柽柳扦插幼苗叶片中叶绿素含量先升高后降低,但过高的盐胁迫会破坏叶绿素的合成。(3)柽柳扦插幼苗叶片SOD和POD活性随盐胁迫增强先升高后降低,通过提高SOD和POD活性来清除细胞内多余的活性氧自由基,但活性氧自由基积累过多时,膜脂过氧化作用会破坏细胞膜的稳定性,导致抗氧化酶活性降低。(4)柽柳扦插幼苗叶片MDA含量随盐胁迫的增强先升高后降低。在土壤含盐量0.4%—1.2%范围内,MDA含量虽高于CK,但各盐分处理之间差异不显著。在含盐量为1.6%时,叶片细胞受到膜脂过氧化作用加强,MDA含量显著升高,但含盐量为2.0%时,MDA含量降低。     

发酵法炮制何首乌的初步研究

为了筛选出可以专一性降解何首乌中蒽醌类成分而不破坏其有效成分二苯乙烯苷的菌种,降低何首乌的毒副作用,我们建立了一种炮制何首乌的新方法.采用HPLC法和UV分光光度计法,对不同菌株发酵的何首乌样品及其发酵前后的化学成分进行比较分析.结果显示:米根霉(Rhizojpus oryzae)、菌株YMS-010(Mucor.sp.)发酵样品的游离型总蒽醌、大黄素、大黄素甲醚的含量均有较大幅度的降低.菌株YMS-006(Aspergillus)、黑曲霉(Aapergillus nigers)、酿酒酵母(Saccharomyces cerevisiae)三株菌株发酵何首乌样品有未知成分产生,且含量较高.通过筛选发现米根霉、菌株YMS-006具有专一性降解蒽醌类成分而不破坏二苯乙烯苷的能力,获得了具有发酵炮制作用的菌株.     

根结线虫对黄瓜叶片氮磷含量、土壤pH和酶活性的影响

通过盆栽试验,采用人工接种的方法研究了接种根结线虫对黄瓜植株根际和非根际土壤pH值、土壤酶活性及叶片N、P含量的影响.结果表明:根际土壤pH值在接种量达到每株6000个时才显著降低;随着接种量的增加,叶片N、P含量、根际土壤过氧化物酶、根际和非根际土壤多酚氧化酶活性逐渐降低,根际土壤过氧化氢酶活性却逐渐升高,非根际土壤pH值先升高后降低,非根际土壤过氧化氢酶活性没有明显的变化规律.接种根结线虫后,根际土壤脲酶活性显著降低,根际和非根际土壤磷酸酶活性、非根际土壤过氧化物酶活性仅在较高接种量时才显著降低.根际土壤pH值、酶活性及叶片N、P含量之间多数呈极显著相关,而非根际土壤pH值、酶活性及叶片N、P含量之间只有部分呈极显著相关.     

何首乌生长过程中二苯乙烯苷的含量变化

对1～4年生何首乌的主要药用成分二苯乙烯苷含量在不同时期、不同器官中的变化进行测定分析,以明确何首乌的最佳采收时间和采收部位.结果显示:何首乌各器官中块根的二苯乙烯苷含量最高,为5.35%,其次为老根和老茎,营养器官的幼嫩部分及生殖器官中的含量都很低;随着生长年限的增加,块根中二苯乙烯苷含量逐渐增加.块根中二苯乙烯苷的含量从6月至10月逐渐升高,10月含量达到最高,为7.09%,然后含量逐渐降低.何首乌块根各部分中二苯乙烯苷的含量差异较大,周皮含量最高,为9.64%,薄壁组织最低.从二苯乙烯苷的含量变化考虑,10月采收何首乌较为合理,且老根和老茎应进行综合利用.     

重庆三峡库区柑橘硼营养状况及其影响因子

为了解重庆三峡库区柑橘叶片硼营养状况及其影响因子,在该区域12个主产县(区)的代表性果园采集叶片样品954份和土壤样品302份,测定叶片硼含量,并分析了土壤有效硼、土壤pH值、品种、砧木和树龄对叶片硼营养的影响.结果表明: 该区域柑橘叶片硼含量不足(<35 mg·kg^-1)的果园比例达41.6%,土壤有效硼含量不足(<0.5 mg·kg^-1)的果园比例高达89.4%,柑橘叶片硼含量与土壤有效硼含量的相关性未达显著水平.土壤pH值、品种、砧木和树龄均影响叶片硼含量.pH值4.5～6.4土壤上的柑橘叶片硼含量显著高于pH值6.5～8.5土壤上的柑橘;品种间叶片硼含量为:温州蜜柑>柚类>夏橙>普通甜橙>杂柑>脐橙;枳砧和酸柚砧柑橘叶片硼含量显著高于枳橙砧和红橘砧柑橘;3～8年生柑橘树叶片硼含量适宜(35～100 mg·kg^-1)样品比例比8年生以上柑橘树高6.6%.     

模拟酸雨对苦楝生理生态特性的影响

以盆栽一年生苦楝(Melia azedarach)为试材,4个p H梯度(5.6(CK)、4.5、3.5和2.5)的模拟酸雨每2 d喷洒叶片1次,探讨处理20、40和60 d对叶片叶绿素(Chl)含量、可溶性蛋白含量、细胞膜透性、MDA含量、抗氧化酶活性等的影响。结果表明:随处理时间的延长,可溶性蛋白含量在p H 4.5下呈先升后降趋势,最大增幅为10.3%,p H 3.5和p H 2.5呈降低趋势,最大降幅为42.9%;质膜透性和MDA含量均显著增加,最大增幅分别为84.6%和145.5%;SOD在p H 4.5下呈升高趋势,p H 3.5下先升高后降低,p H 2.5下呈降低趋势,最大增幅和降幅分别为47.9%和20.9%;CAT在p H 4.5下呈先升后降趋势,p H 3.5和p H 2.5下呈降低趋势,最大增幅和降幅分别为23.0%和27.0%;POD在p H 4.5和p H 3.5下呈升高趋势,p H 2.5呈降低趋势,最大增幅和降幅依次47.1%和17.6%;Chla、Chlb和叶绿素总量减少,最大降幅分别为39.0%、37.0%和38.3%。结合叶片的外观形态、脱落率和株高增量发现,p H 3.5下苦楝叶片变黄,脱落率显著增加(P0.05),p H 2.5下叶片严重变形,株高显著降低(P0.05),由此认为,苦楝耐酸雨的阈值大约为p H 3.5。     

土壤pH值对烤烟叶片生理生化特性的影响

烟草生长初期,超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量与pH增长呈正相关,而过氧化氢酶(CAT)和过氧化物酶(POD)活性则随着pH的增加而下降,pH值6.5和7.5时叶绿素含量和净光合速率(Pn)较高,旺长期达到高峰;生长后期,各处理的MDA含量和POD活性最高,SOD、CAT活性最低.各pH值处理的叶片中,叶绿素含量、Pn下降,比叶重达到高峰,但pH 8.5下的烟叶中叶绿素含量高,Pn大,比叶重较小.pH 6.5和7.5下的烟叶中蛋白质和可溶性糖总体含量高于其它pH的.烟碱含量在pH 5.5时最高,pH 8.5时最低.     

土壤酸度对脂松苗木光合和叶绿素荧光的影响

脂松（Pinus resinosa）是北美东北部地区重要的造林树种之一,2004年在我国东北东部山地引种栽培初步获得成功.为扩大脂松栽培范围,采用盆栽方法研究不同土壤酸度（pH分别为4.5、5.5、6.5、7.5和8.0）对脂松苗木光合和叶绿素荧光参数的影响,确定其适生的土壤酸度范围.结果表明：土壤酸度对脂松苗木针叶叶绿素a、b和叶绿素含量、类胡萝卜素含量、净光合速率(P_n)和荧光参数F_o、F_m、F_v、F_v/F_m、Φ_PSⅡ有显著影响（P<0.05）.pH 5.5处理的叶绿素含量和P_n最高,分别比pH 7.5和8.0 处理增加41%、50%和61%、88%;pH 7.5和8.0处理时最低.pH 5.5时叶绿素荧光参数F_v/F_m和Φ_PSⅡ均最高,分别比pH 7.5和8.0处理增加8%、12%和22%、35%;pH 7.5和8.0时则受到明显抑制.土壤pH值为5.5时最适宜脂松生长.     

pH值对日本三角涡虫种群增长、无性生殖及6种酶活力的影响

应用种群累积培养法,就培养液的pH值对日本三角涡虫的生存、种群增长、无性生殖以及涡虫超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-PX)、乳酸脱氢酶(LDH)、Na -K -ATP酶和Ca2 -Mg2 -ATP酶等6种酶活力的影响进行了探讨.结果表明,涡虫存活的pH上限为11.0,下限为3.0,涡虫存活的最适pH范围为4.5-8.5;pH值对涡虫种群增长有显著影响,种群密度及种群瞬时增长率均随pH的不同而明显改变.培养27d后,pH 4.0-9.0时涡虫种群为正增长:pH 4.5-6.5时,涡虫种群密度最高,pH 7.5-8 .5时次之,pH 7.0时较低,pH 4.0和9.0时最低;而pH 9.5时为负增长.当pH值偏离7.0(偏酸或偏碱)时CAT、GSH-PX、Na -K -ATP酶和Ca2 -Mg2 -ATP酶活力整体均呈现增加的趋势,而SOD和LDH活力整体呈下降趋势.pH值偏离7.0(偏酸或偏碱)时涡虫6种酶活力均产生明显的变化,这与pH 4.5-6.5和pH 7.5-8.5时涡虫具有比pH 7.0实验组涡虫较高的无性横裂生殖率之间可能存在一定的内在联系.本文研究结果可为实验室培养日本三角涡虫提供适宜的pH值指标.     

水分胁迫对刺槐叶和根谷胱甘肽抗氧化系统的影响

在人工控水条件下,采用土壤最大持水量70%、55%、40%的水分处理模拟环境中的正常水分、轻度和重度水分胁迫处理,测定了刺槐叶片和根系中还原型谷胱甘肽(GSH)和还原型抗坏血酸(AsA)含量以及谷胱甘肽还原酶(GR)、谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶(SOD)活性,以探讨水分胁迫条件下刺槐谷胱甘肽抗氧化系统的保护作用.结果显示:各水分处理的刺槐叶片GSH和AsA含量及GR 和SOD活性均明显高于根,根中GSH-Px活性只有在重度水分胁迫处理下大于叶片.随水分胁迫加剧,刺槐GSH含量在叶片中先升高后降低,在根中不断升高;AsA含量在叶中持续降低,在根中先升高后降低;GR活性在叶片和根系中都会降低,GSH-Px和SOD活性在叶中先升高后降低,在根中均持续升高.研究表明,刺槐谷胱甘肽抗氧化系统的GSH和GSH-Px对干旱胁迫诱发的活性氧清除起主要作用,同时提高GSH含量和GSH-Px活性是刺槐应对干旱胁迫的重要措施.     

Y-chromosome Data and Tribal Affiliations of Allenopithecus and Miopithecus

The phylogeny of Old World monkeys has remained unresolved in part because of a lack of resolution in the Cercopithecinae. Competing morphological hypotheses have had Allen's swamp monkey (Allenopithecus nigroviridis) and the talapoins (Miopithecus spp.) as basal branches of either the tribe Cercopithecini or the tribe Papionini. Previous molecular analyses have not adequately addressed the issue. To better understand the evolutionary history of these primates, we sequenced and subjected to phylogenetic analysis 3.1 kb of 2 loci (TSPY and SRY) from the non-recombining portion of the Y-chromosome. Individuals from the genera Allenopithecus, Miopithecus, Erythrocebus, Chlorocebus, and Cercopithecus were surveyed and their sequences compared with those previously published for the Papionini and Colobinae. The results suggest Allenopithecus and Miopithecus are more closely related to the Cercopithecini than Papionini. Our data also support the hypothesis that within the Cercopithecini, Erythrocebus and Chlorocebus share a close evolutionary relationship, distinct from the other members of the tribe.     

Nystatin and killer toxin sensitivity of free and immobilizedSaccharomyces cerevisiae

The inhibitory effect of nystatin and killer toxin on the growth of free and covalently-immobilizedSaccharomyces cerevisiae cells was studied. The resistance of immobilized cells to both agents was accompanied by increased amounts of phospholipids and sterols. The possible relationship between these changes in the membrane composition and the transduction of a signal across the cytoplasmic membrane is discussed.     

The hernandez and fernandez genes of Drosophila specify eye and antenna

The formation of different structures in Drosophila depends on the combined activities of selector genes and signaling pathways. For instance, the antenna requires the selector gene homothorax, which distinguishes between the leg and the antenna and can specify distal antenna if expressed ectopically. Similarly, the eye is formed by a group of "eye-specifying" genes, among them eyeless, which can direct eye development ectopically. We report here the characterization of the hernandez and fernandez genes, expressed in the antennal and eye primordia of the eye-antenna imaginal disc. The predicted proteins encoded by these two genes have 27% common amino acids and include a Pipsqueak domain. Reduced expression of either hernandez or fernandez mildly affects antenna and eye development, while the inactivation of both genes partially transforms distal antenna into leg. Ectopic expression of either of the two genes results in two different phenotypes: it can form distal antenna, activating genes like homothorax, spineless, and spalt, and it can promote eye development and activates eyeless. Reciprocally, eyeless can induce hernandez and fernandez expression, and homothorax and spineless can activate both hernandez and fernandez when ectopically expressed. The formation of eye by these genes seems to require Notch signaling, since the induction of ectopic eyes and the activation of eyeless by the hernandez gene are suppressed when the Notch function is compromised. Our results show that the hernandez and fernandez genes are required for antennal and eye development and are also able to specify eye or antenna ectopically.     

Ovule and seed anatomy ofCistaceae and relatedMalvanae

Ovule and especially seed anatomy of eight species ofCochlospermaceae, Bixaceae, Cistaceae, Monotoideae, Pakaraimaeoideae (two subfamilies ofDipterocarpaceae), andSarcolaenaceae were investigated. All representatives show a bixoid chalazal region in the seed as probable exclusive synapomorphy among angiosperms. The palisade layer of the exotegmen is curved inwards at its proximal end and forms a dome-shaped structure. A plug of hypostase tissue with an annulus/core structure fits into this dome. Moreover, two additional tissue types in the hypostase can be found in some representatives of the group. These and other micromorphological, wood anatomical, and floral morphological characters, indicate that the taxa form a monophyletic group close toMalvales s. str. The form of the starch grains in the endosperm is compared and is described for the first time forPakaraimaea (Dipterocarpaceae) andLeptolaena (Sarcolaenaceae). The position ofDiegodendron close toBixa and the presumably more distant positions ofMuntingia andNeuradaceae are discussed.     

Development and function of Pisolithus and Scleroderma ectomycorrhizas formed in vivo with Allocasuarina,Casuarina and Eucalyptus

The effect of inoculating seedlings of Eucalyptus grandis, Allocasuarina littoralis and Casuarina equisetifolia with two isolates of Pisolithus and two isolates of Scleroderma from under eucalypts was examined in a glasshouse trial. Ectomycorrhizas formed extensively on Eucalyptus (23–46% fine roots ectomycorrhizal) and Allocasuarina (18–51% fine roots ectomycorrhizal). On Casuarina, the fungi were either unable to colonize the rhizosphere (one isolate of Pisolithus), or sheathed roots, resembling ectomycorrhizas, formed on 1–2% of the fine roots. Colonization of roots by one isolate of Scleroderma resulted in the death of Casuarina seedlings. Inoculation with fungi increased shoot dry weight by up to a factor of 32 (Eucalyptus), 4 (Allocasuarina) and 3 (Casuarina). Ectomycorrhizas formed in associations with Eucalyptus and Allocasuarina had fully differentiated mantles and Hartig nets in which the host and fungal cells were linked by an extensive fibrillar matrix. Sheathed roots in Casuarina lacked a Hartig net, and the epidermis showed a hypersensitive reaction resulting in wall thickening and cell death. The sheaths are described as mantles since the density and arrangement of the hyphae in the sheaths was similar to that in mantles of the eucalypt ectomycorrhizas. The intercellular carbohydrate matrix was not produced in the Casuarina mantle in association with Pisolithus, hence the mantle was not cemented to the root. These structures differ from poorly compatible associations described previously for Pisolithus and Eucalyptus. The anatomical data indicate that ectomycorrhizal assessment based on surface morphological features may be misleading in ecological studies because compatible and incompatible associations may not be distinguishable.     

Amino acids and sugars in nectar,and their putative evolutionary significance

Individual amino acids and sugars from flower nectar of 32 plant species with different pollination systems were quantified and compared. Data show that there is no correlation between sugar and amino acid concentration. Furthermore there is no correlation between composition and concentration of amino acids and evolutionary advancement, nor any direct relation with pollination systems. However, higher sugar concentrations are often linked with more advanced morphological characters. Nectars from pierced or damaged flowers or nectars contaminated with pollen exhibit modifications and increases in amino acid composition. The presence of proline probably indicates such pollen contamination. Most pollinating animals depend on flower nectar in their energetic requirements, yet innumerable alternative amino acid and protein sources exist. Future research has to consider the relationship between nutritional requirements of pollinating animals and dependence on flower nectars.Dedicated to Prof. Dr.L. van der Pijl, Den Haag, in honour of his 80th birthday.     

Cyclooxygenase inhibitory and antioxidant cyanidin glycosides in cherries and berries

Anthocyanins from tart cherries, Prunus cerasus L. (Rosaceae) cv. Balaton and Montmorency; sweet cherries, Prunus avium L. (Rosaceae); bilberries, Vaccinum myrtillus L. (Ericaceae); blackberries, Rubus sp. (Rosaceae); blueberries var. Jersey, Vaccinium corymbosum L. (Ericaceae); cranberries var. Early Black, Vaccinium macrocarpon Ait. (Ericaceae); elderberries, Sambucus canadensis (Caprifoliaceae); raspberries, Rubus idaeus (Rosaceae); and strawberries var. Honeoye, Fragaria x ananassa Duch. (Rosaceae), were investigated for cyclooxygenase inhibitory and antioxidant activities. The presence and levels of cyanidin-3-glucosylrutinoside 1 and cyanidin-3-rutinoside 2 were determined in the fruits using HPLC. The antioxidant activity of anthocyanins from cherries was comparable to the commercial antioxidants, tert-butylhydroquinone, butylated hydroxytoluene and butylated hydroxyanisole, and superior to vitamin E, at a test concentration of 125 microg/ml. Anthocyanins from raspberries and sweet cherries demonstrated 45% and 47% cyclooxygenase-I and cyclooxygenase-II inhibitory activities, respectively, when assayed at 125 microg/ml. The cyclooxygenase inhibitory activities of anthocyanins from these fruits were comparable to those of ibuprofen and naproxen at 10 microM concentrations. Anthocyanins 1 and 2 are present in both cherries and raspberry. The yields of pure anthocyanins 1 and 2 in 100 g Balaton and Montmorency tart cherries, sweet cherries and raspberries were 21, 16.5; 11, 5; 4.95, 21; and 4.65, 13.5 mg, respectively. Fresh blackberries and strawberries contained only anthocyanin 2 in yields of 24 and 22.5 mg/100 g, respectively. Anthocyanins 1 and 2 were not found in bilberries, blueberries, cranberries or elderberries.     

Molecular identification and differentiation of Brevibacterium species and strains

Amplified ribosomal DNA restriction enzyme analysis (ARDRA), pulsed field gel electrophoresis (PFGE) and ribotyping were used to differentiate among 24 strains of Brevibacterium linens, Brevibacterium casei and Brevibacterium epidermidis obtained from type culture collections or isolated from various smear ripened cheeses. ARDRA was applied to the 16S rDNA. B. linens was shown to be a quite heterogenic group with 2 to at least 4 copies of rrn operons per strain with aberrant nucleotide sequences. AccI gave genus specific restriction patterns and was used to separate Brevibacterium from Corynebacterium species. The expected species specificity of TaqI applied to B. linens type culture strains, but not to all strains isolated from cheese. By AvaI restriction, B. casei and B. linens were differentiated from B. epidermidis and the orange pigmented Arthrobacter casei, a new species of coryneform bacteria; by XmnI restriction, B. linens and B. epidermidis were differentiated from B. casei. One of 4 B. linens genotypes could not be distinguished from B. casei by this method. Here, the typical orange B. linens pigments were used for classification, which was confirmed by partial sequencing of the 16S rDNA.     

Pericarp structure and phylogeny of theLamiaceae-Verbenaceae-complex

Pericarp structure was investigated in 158 species of the familiesLamiaceae andVerbenaceae. Data from 221 out of 262 genera ofLamiaceae s.l. and a few ofVerbenaceae s.str. were collected in a table. A cladistic analysis was performed on the basis of pericarp characters only. The abandonment of subfam.Pogostemonoideae as a taxonomic unit is considered. Examples of groups given additional support by similarities in pericarp characters are: (1) the gynobasic-styled labiates (subfamiliesPogostemonoideae, Lamioideae, Nepetoideae); (2) aLamioideae-Pogostemonoideae-group; (3)Nepetoideae; (4) aWestringia-Hemigenia-Hemiandra-Microcorys group (in subfam.Chloranthoideae); (5) aLepechinia-Chaunostoma-group (inNepetoideae); (6) aPrunella-Cleonia-group (inNepetoideae).