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1.
以苹果园内2年生紫花苜蓿为材料,设0.150、0.225(正常水平)和0.300m3/m2共3个灌溉量处理,研究不同灌溉量对紫花苜蓿生物量、光合生理指标、叶绿素含量、脯氨酸含量及电导率的影响。结果显示:(1)灌溉量对紫花苜蓿地上生物量有显著的影响,且随灌溉量的增加而增加;灌溉量大的处理苜蓿吸收根分布有浅层化趋势。(2)不同灌溉量处理的紫花苜蓿叶片净光合速率(Pn)与光合有效辐射(PAR)的变化趋势基本一致,均表现为在低PAR时Pn迅速增加,达到一定PAR后,Pn增幅渐趋平缓;净光合速率均随灌水量的增加而增加。(3)灌溉后土壤含水率和苜蓿叶片叶绿素含量随灌溉量的增加而升高,苜蓿叶片相对电导率随着灌水量的增加而呈现降低的趋势,低灌溉量可导致紫花苜蓿叶片中脯氨酸含量大量积累。研究表明,适当的灌溉可以有效改善苹果园土壤水分状况,提高紫花苜蓿光合生产力。  相似文献   

2.
以紫花苜蓿品种‘甘农3号’和‘陇东苜蓿’为研究材料,采用室外(防雨网室)盆栽营养液砂培法,研究了2种氮素形态(NO3--N,NH4+-N)的5个氮素水平(0、105、210、315、420mg·L-1)处理对叶片输导组织解剖结构及光合特性的影响。结果显示:(1)与无氮处理相比,供氮处理下‘甘农3号’和‘陇东苜蓿’输导组织的解剖结构和光合特性发生明显变化,叶片输导组织维管束、木质部和韧皮部面积显著增大,导管数显著增多,净光合速率、气孔导度、叶面积和叶绿素含量均显著增加,且在210mg·L-1供氮水平下达到最大值。(2)2种氮素形态相比,‘甘农3号’和‘陇东苜蓿’叶片输导组织维管束面积、木质部面积、韧皮部面积、导管数、净光合速率、气孔导度、叶面积、叶绿素含量均表现为NH4+-N处理好于NO3--N处理。(3)2品种相比,叶片输导组织维管束面积、木质部面积、韧皮部面积、导管数、净光合速率、气孔导度、叶面积、叶绿素含量表现为‘甘农3号’大于‘陇东苜蓿’。研究表明,氮素能通过改善紫花苜蓿叶片输导组织的解剖结构和光合特性,促进紫花苜蓿光合作用;各处理中以NH4+-N、210mg·L-1表现最佳,维管束面积最大,木质部、韧皮部面积大且发育好,导管数最多,而且‘甘农3号’表现更优。  相似文献   

3.
2个种源栓皮栎对干旱及复水的光合生理响应   总被引:1,自引:0,他引:1  
为了探究干旱复水对2个种源栓皮栎幼苗光合生理特性的影响,测定了不同水分处理(正常供水、轻度干旱、中度干旱和重度干旱)及复水处理下盆栽栓皮栎幼苗生长、叶片气体交换及叶绿素荧光参数。结果表明:随着干旱胁迫程度的加重,幼苗生长受到的抑制程度增加;气体交换参数净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率(WUE)均呈下降的趋势,而气孔限制值(Ls)呈上升趋势,在重度干旱胁迫下气体交换参数变化幅度最大;叶片非光化学猝灭系数(NPQ)呈现先上升后下降的趋势,PSII潜在活性(Fv/Fo)、最大光化学效率(Fv/Fm)、电子传递速率(ETR)和实际光量子效率(ΦPSⅡ)均呈下降趋势。主要叶绿素荧光参数对干旱胁迫的响应与气体交换参数一致,即重度胁迫对光合电子传递造成了最严重的损伤。干旱后复水,导致栓皮栎光合生理参数不同程度的恢复。就种源地而言,老君山种源的幼苗在干旱胁迫下主要参数的变化程度大于北坡山种源的幼苗,且在复水后老君山种源幼苗恢复程度低于北坡山种源,表明北坡山种源的栓皮栎抗旱力和恢复力均强于老君山种源。  相似文献   

4.
为了解遮荫对裸花紫珠(Callicarpa nudiflora)幼苗生长和药材质量的影响,研究了遮荫处理(遮荫30%、50%、70%和对照0%)下2年生裸花紫珠苗的光合气体交换参数、叶绿素荧光参数、光合色素和总黄酮含量的变化。结果表明,无遮荫或遮荫30%下,裸花紫珠的叶片净光合速率(Pn)日变化曲线呈典型的双峰型,而随遮荫程度的增加,Pn日变化曲线逐渐转变为单峰型。蒸腾速率(Tr)和气孔导度(Gs)日变化曲线呈单峰型,且峰值随着遮荫程度的增加而降低。PSII最大光化学效率(Fv/Fm)和潜在活性(Fv/Fo)的日变化曲线呈"V"型,且两者均随遮荫程度的增加而升高。幼苗叶片的叶绿素a(Chl a)、叶绿素b(Chl b)、类胡萝卜素(Car)含量随遮荫程度的增加而显著增加(P0.05),而Chl a/b和Car/Chl却随遮荫程度的增加而下降。随遮荫程度的增加,叶片中总黄酮含量呈先上升后下降的趋势,以遮荫30%为最大。因此,裸花紫珠幼苗最适宜生长在无遮荫条件下,但为获得更高的总黄酮含量,可以选择30%遮荫处理。  相似文献   

5.
水分对苜蓿叶片光合特性的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
 采用田间试验, 对每茬灌水3次(W3)、2次(W2)、1次(W1)和不灌水(W0)四种条件下的土壤水分, 苜蓿(Medicago sativa) 叶片的叶绿素荧光参数、气孔导度(Gs)、净光合速率(Pn)和蒸腾速率(Tr)进行测定。结果表明, 灌水提高了苜蓿叶片的原初光能转换效率(Fv/Fm)、Pn和Tr, 并随着灌水量的增加而增加。苜蓿叶片的Fv/Fm、Pn和Tr的日均值与土壤含水量均呈极显著正相关关系。苜蓿叶片的Pn与Fv/Fm和光合有效辐射(PAR)的乘积呈正相关关系。灌水还改变了苜蓿叶片Pn的日变化格局。灌水较多的处理(W3和W2), 苜蓿叶片没有出现光合“午休”现象, Pn的日变化趋势呈现“单峰”型。而灌水较少和不灌水的处理(W1和W0), 苜蓿叶片出现了明显的光合“午休”现象, 其Pn的日变化进程呈现“双峰”型。在相同的水分条件下, 初花期苜蓿叶片的Pn高于再生期的, Tr则相反。  相似文献   

6.
CO2浓度升高对龙血树和春羽生长及光合生理的影响   总被引:1,自引:0,他引:1  
采用开顶式气室(OTC)控制模拟环境,研究了二氧化碳(CO2)浓度升高对龙血树和春羽叶片光合生理及叶绿素荧光参数的影响。结果表明:(1)随着CO2浓度增加,龙血树和春羽幼苗叶面积和株高均呈显著增加趋势。(2)龙血树和春羽幼苗叶片净光合速率随着CO2浓度的升高均呈先增加后降低的趋势,而同期蒸腾速率和气孔导度显著降低。(3)随着CO2浓度的增加,龙血树和春羽幼苗叶片最大光量子产量、实际光能转化效率均呈先升后降的趋势,而同期非光化学猝灭系数呈先降低后升高的趋势;光化学猝灭系数总体上也呈先升高后降低的趋势,但差异不显著。研究表明,一定时间的高浓度CO2处理提高了龙血树和春羽的净光合速率,促进了植物的生长,但随着处理时间的延长,这种促进作用逐渐降低进而消失,并以春羽幼苗表现得更突出;即高浓度CO2可能破坏了龙血树及春羽生长后期光系统Ⅱ反应中心结构,导致叶片光合能力降低。  相似文献   

7.
酸雨胁迫条件下紫花苜蓿种子萌发和幼苗生理特性的变化   总被引:2,自引:0,他引:2  
以紫花苜蓿种子皇冠(Phabulous)为材料,研究不同pH值的模拟酸雨对皇冠(Phabulous)种子萌发及幼苗生理特性的影响。分别测定了发芽率、发芽势、发芽指数、活力指数和种子脱氢酶含量、幼苗鲜重、幼苗干重、幼苗叶绿素含量、叶片导电率等指标。结果表明,种子的各项发芽指标及幼苗鲜重、脱氢酶活力、叶绿素含量等随酸雨pH值减小整体呈降低趋势,叶片浸泡液电导率则随酸雨pH值减小而呈增大趋势。  相似文献   

8.
比较盆栽 生榕树和两栖型树的形态差异、叶片叶绿素含量、叶绿素荧光特性和气体交换的日变化。两栖型榕树具有较发达的气生根和水生不定根,叶片比陆生榕树宽,并有向中生性 倾向,陆生榕树的叶绿素含量比两栖榕树高,净光合速率略高于水培两栖型榕树,但明显高于土培两栖型榕树,蒸腾速率以水培两栖型树最高,陆生榕树次之,土培两栖型榕树最低,线性回归分析表明,三者的叶片气孔导度与净光合速率变化均呈正相关,气孔导度的变化  相似文献   

9.
采用人工控制手段,研究短期夜间低温对秋茄幼苗叶片光合特性、色素含量、抗氧化系统、细胞膜透性以及碳氮代谢相关酶活性的影响。结果表明:(1)低温16 h内,秋茄的净光合速率、气孔导度、气孔限制值均显著降低,而胞间CO2浓度显著增加。(2)低温低于8 h,叶片叶绿素含量、类胡萝卜素含量以及Chl a/Chl b比值均未产生显著变化,而Car/Chl 比值显著增加。低温12、16 h,其叶片光合色素均下降,尤其白天下降幅度更大。(3)低温16 h内叶片可溶性总糖一直增加,而蔗糖含量、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)活性均在低温12 h后下降。(4)低温16 h内叶片可溶性蛋白、游离氨基酸含量以及羧肽酶活性均增加,而低温8 h时叶片内肽酶活性就开始下降。(5)低温16 h内叶片相对电导率、MDA均增加,而叶片POD活性均下降,尤其夜间下降更明显。另外,低温4、16 h能显著降低叶片SOD活性。以上说明,低温16 h时秋茄叶片光合作用的下降主要是因为非气孔导度限制引起,这主要与光合色素下降、抗氧化酶活性降低有关。此外,短期夜间低温通过影响SS、SPS、内肽酶以及羧肽酶活性,从而抑制了秋茄自身的碳氮代谢调控能力。  相似文献   

10.
NaCl胁迫对西瓜幼苗生长和光合气体交换参数的影响   总被引:2,自引:0,他引:2  
以早春红玉品种为材料,采用营养液水培法,研究了不同浓度NaCl胁迫对西瓜幼苗生长、叶片光合气体交换参数、质膜透性和脯氨酸含量的影响.结果表明:25 mmol·L-1NaCl处理9 d后对西瓜幼苗生长有促进作用,>75 mmol·L-1NaCl处理则显著抑制幼苗生长;NaCl处理显著提高了叶片光合色素含量,并在100 mmol·L-1NaCl处理下达到最大;叶片净光合速率、气孔导度和蒸腾速率均随NaCl浓度提高而显著降低;胞间CO2浓度随NaCl浓度提高呈先降低后升高的趋势,在75 mmol·L-1NaCl处理下降到最小;气孔限制值随NaCl浓度提高而增加,在75 mmol·L-1NaCl处理下达到最大值后趋于稳定;水分利用率随NaCl浓度提高呈先增加后降低的趋势,在75 mmol·L-1NaCl处理下达到最大;叶片质膜透性和脯氨酸含量均随NaCl浓度提高而显著增加.结果说明:NaCl胁迫显著抑制了西瓜叶片光合作用,且低浓度处理下光合速率降低的主要原因是气孔因素限制,高浓度胁迫下则转变为非气孔因素限制.  相似文献   

11.
Four different strains ofLactobacillus delbrueckii subsp.bulgaricus (Ss1 and Yop12) andStreptococcus salivarius subsp.thermophilus (Ss2 and Yop9) were isolated from two different yogurt sources in Argentina. In medium containing different carbon sources: lactose, fructose, sucrose or glucose plus fructose, the growth of a mixed culture (Yop12+Ss2) shows stimulation ofS. thermophilus and inhibition ofL. bulgaricus with respect to pure cultures. Both microorganisms in mixed culture grew less well on glucose plus galactose. However, in medium with glucose or galactose, both microorganisms were stimulated.  相似文献   

12.
Bukharie HA 《Mycopathologia》2002,153(4):195-198
Demographic information, risk factors, therapy, and outcome for all patients who had candidemia at King Fahad teaching hospital Al-khobar, between January 1995 and January 2000 were retrospectively reviewed. Thirty-two candidemic patients were identified. Candida parapsilosis was the most frequently isolated species (44%), followed by Candida tropicalis (25%), Candida albicans (19%), Candida krusei (6%), Candida glabrat a (3%), and Candida guilliermondi (3%). Risk factors included recent broad-spectrum antibiotics use (100%), ICU residency (71%), central venous catheters (66%), recent surgery (56%), total parenteral nutrition (43%), and immunosuppressive therapy (31%). Fluconazole was used before the onset of candidemia in only two patients. The overall mortality rate was 44%. Eight (25%) episodes of candidemia were not diagnosed and treated before the patient's demise. In view of the high mortality rate associated with hematogenous candidiasis, and lack of sensitive and specific laboratory tests necessary for the premortem diagnosis of infection, empirical antifungal therapy is recommended for high-risk patients. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

13.
报道了卫矛属(Euonymus)一新变种——腥臭卫矛(Euonymus sanguineus var.paedidus L.M.Wang)。该新变种与原变种石枣子(Euonymus sanguineus Loes.var.sanguineus)相似,但其独特的强烈腥臭花不仅明显可与石枣子区别,而且也有别于卫矛属中所有其他种类。另外,该变种叶柄极短,一般短于5mm,可以与原变种区别。对腥臭卫矛的分布与生境做了简略讨论。  相似文献   

14.
通过野外调查、标本查阅及文献考证,订正了华南吊灯花属(Ceropegia Linn.)植物,将狭瓣吊灯花(C. angustilimba Merr.)从吊灯花(C. trichantha Hemsl.)的异名中予以恢复,提供了二者的形态描述,确认华南地区记录的柳叶吊灯花(C. salicifolia H. Huber)实为剑叶吊灯花(C. dolichophylla Schltr.)的错误鉴定,并提供了后者的形态描述。  相似文献   

15.
代洁  杜巍 《生物资源》2021,(6):617-624
泽泻科(Alismataceae)是现存最原始的单子叶植物类群之一,慈姑属(Sagittaria)是泽泻科相对进化的分类群,地域分布广泛,其物种大多集中分布于北温带,且有种间同域分布现象。为了探究同域分布物种之间的杂交可能性,我们通过选取同域分布且在系统进化树上具有代表性的冠果草(S.guayanensis subsp. lappula)、小慈姑(S. potamogetonifolia)、利川慈姑(S. lichuanensis)和野慈姑(S. trifolia)为研究对象,调研中国数字植物标本馆(CVH)的标本信息和已有文献,分析这4种慈姑的地理分布格局,并分别以这4种慈姑为母本进行人工授粉实验以检验种间杂交的可能性。基于对1 172份4种慈姑属腊叶标本的分析,表明这4种慈姑在福建省武夷山地区存在同域分布情况。通过对4种慈姑之间的人工授粉实验结果分析表明,冠果草、小慈姑、利川慈姑和野慈姑异种授粉后均出现心皮膨大现象,所有异种授粉产生的种子均不可育,败育胚种子比例各不相同,且该比例与父本和母本在系统进化树上的位置有关。  相似文献   

16.
The alkane and fatty acid composition of the lipid extracts from leaves of 14 populations ofCondalia: C. microphylla f.xanthocarpa, C. microphylla f.erythrocarpa, C. microphylla f.melanocarpa, C. montana, andC. buxifolia, were determined by gas chromatography. Seventeen alkanes and 14 fatty acids were investigated and a predominance of nonacosane, hentriacontane, palmitic and linoleic acids in all species was found.  相似文献   

17.
Samples from soils planted to millet and sorghum from Lesotho, Nigeria, and Zimbabwe were processed and a total of 3,291Fusarium cultures were recovered. Of these 1,296 cultures were isolated from plant debris and 1,995 cultures were recovered from soil dilutions. The most prevalent species recovered wereF. oxysporum (37%),F. equiset (30%),F. solani (14%),F. moniliforme (6%),F. compactum (5%),F. nygamai (4%), andF. chlamydosporum (2%). OtherFusarium species isolated wereF. merismoides, F. polyphialidicum, F. graminearum, F. subglutinans, F. sambucinum, F. longipes, F. semitectum, F. dimerum, F. lateritium, and a group of cultures designated as population A which resembleF. camptoceras. Fusarium equiseti was the predominant species in soil samples from Nigeria and Zimbabwe, whileF. oxysporum was the predominant species recovered from soil from Lesotho.Contribution No. 1881, Fusarium Research Center, Department of Plant Pathology, The Pennsylvania State University.  相似文献   

18.
The perennial taxa ofCrucianella in Asia form a coherent group, apparently diploid (x = 11) and outbreeding throughout, and should be placed into sect.Roseae. This Irano-Turanian group has its centre of diversity in the mountain systems south of the Caspian Sea and reaches with outposts NE. and E. Anatolia, NE. Iraq, S. Iran and C. Asia. Four species and 13 subspecies (within the polymorphicC. gilanica) are recognized, described (partly as new), and illustrated (Figs. 1–6). Conspectus, keys and distribution maps (Figs. 7 and 8) as well as plesio- and apomorphic character states and data on size of areas are provided (Table 1). There is an obvious correlation between more plesiomorphic taxa with smaller areas in the distribution centre of the group, and more apomorphic taxa with larger areas towards its periphery (Fig. 9). These findings are linked to a working hypothesis on the evolution of the group.Dedicated to Prof. DrLothar Geitler on the occasion of his 90th birthday.  相似文献   

19.
The production of antimicrobial activities as well as the presence of bacteriocin structural genes (entA, entB, entP, entQ, cylL, entAS-48, bac31, and entL50A/B) were studied in 140 non-selected faecal enterococcal isolates recovered from wild animals. Eight different indicator strains (including Listeria monocytogenes, Pediococcus pentosaceus, and different enterococcal species) were used for antimicrobial activity detection. Twenty-five of the 140 enterococci (18%) showed antimicrobial activity against L. monocytogenes and 33 additional isolates (24%) showed antimicrobial activity against other indicator strains, but Listeria. At least one bacteriocin structural gene was detected in 17 of the 25 enterococci with antimicrobial activity against L. monocytogenes and different combinations of entA, entB, entP, entQ, entL50A/B, and cylL genes were detected; entA and entB were the most prevalent detected genes, and they were generally associated. Bacteriocin structural genes were detected in 10 of 33 isolates with antimicrobial activity against indicator strains other than Listeria, and the cylL gene was the most prevalent one, especially in E. faecalis isolates.  相似文献   

20.
This study presents the results of archaeobotanical examination of remains from the medieval complex of Ras in Serbia. The samples were collected from the fortress situated on the hilltop (Gradina) and from a settlement below (Podgradje) during the archaeological excavations of 1972–1984. They were taken primarily from the buildings containing charred cereals dating to the 12th and 13th centuries. The main staple was bread wheat, followed by rye. Grains of barley, oats, and millet were also present. The weeds, including ruderals, were represented by many species. Agrostemma githago (corn cockle) was an important contaminant of the cereal fields. Exceptional finds include a piece of charred round bread, the cereal content of a pot, and peach stone fragments. Previous information about the agriculture and food in medieval Serbia was based solely on documents that were either written after this period or that were not pertinent to the region. This study is the first direct evidence providing information about agriculture and food of the inhabitants of medieval Serbia.  相似文献   

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