CO2倍增对不同氮水平下小麦幼苗根系及叶片NR活性的影响

以小麦品种'小偃22'幼苗为材料,采用开顶式气室和水培实验研究了不同供氮水平(2.5、5.0、10.0和 15.0 mmol·L-1)下小麦幼苗植株生长量、根系形态、有机碳分泌速率和硝酸还原酶(NR)活性对大气CO2浓度升高的响应.结果显示,大气CO2浓度倍增均增加了小麦幼苗各生长阶段根冠生物量以及根系长度、面积、有机碳分泌速率和叶片NR活性.随供氮水平的提高,各生长阶段幼苗根冠生物量、根长和面积以及叶片NR活性呈上升趋势,而有机碳分泌速率呈下降趋势;根冠比变化不同阶段表现不一致,一叶一心期呈下降趋势,二叶一心期和三叶一心期分别以15.0和10.0 mmol·L-1氮水平较高.研究表明,大气CO2浓度升高可促进小麦幼苗根系生长和有机碳分泌速率,提高其氮素同化能力;增加介质供氮有利于高CO2浓度条件下小麦幼苗根冠生长和氮素同化,提高根冠比,减少根系有机碳过度分泌引起的碳损耗.     

NaCl胁迫过程中喷施ALA对菘蓝幼苗生长及主要活性成分含量的影响

以来源于安徽亳州和山西运城的菘蓝（Isatis indigotica Fort.）幼苗为实验材料,对100 mmol·L-1NaCl胁迫条件下喷施50.0、25.0、16.7、12.5和0.0 mg·L-15-氨基乙酰丙酸（ALA）后幼苗部分生长指标、叶片中靛蓝和靛玉红含量以及根中表告依春含量的变化进行了研究。结果表明：在100 mmol·L-1NaCl单一胁迫条件下,来源于安徽亳州的幼苗单株叶鲜质量和叶片中靛蓝和靛玉红含量均低于对照,单株根鲜质量、根冠比以及根中表告依春含量均高于对照;来源于山西运城的幼苗单株叶和根鲜质量、叶片中靛玉红含量和根中表告依春含量均低于对照,根冠比和叶片中靛蓝含量均高于对照。在NaCl胁迫过程中喷施ALA对菘蓝幼苗生长和有效成分的积累均有不同效应。其中,喷施25.0 mg·L-1ALA后安徽亳州产幼苗单株叶和根鲜质量均最高且显著高于NaCl单一胁迫处理组;喷施16.7 mg·L-1ALA后山西运城产幼苗单株叶和根鲜质量均较高但与NaCl单一胁迫处理组无显著差异。喷施50.0 mg·L-1ALA后安徽亳州产幼苗叶片中靛蓝含量最高（0.376 mg·g-1）,喷施25.0 mg·L-1ALA后其叶片中靛玉红含量最高（9.977 mg·g-1）,喷施16.7 mg·L-1ALA后其根中表告依春含量最高（0.229 mg·g-1）,且均显著高于NaCl单一胁迫处理组;喷施16.7 mg·L-1ALA后山西运城产幼苗叶片中靛蓝含量最高（0.282 mg·g-1）,喷施12.5 mg·L-1ALA后其叶片中靛玉红含量和根中表告依春含量均最高（分别为4.526和0.301 mg·g-1）,且均显著高于NaCl单一胁迫处理组。研究结果表明：喷施适宜浓度ALA能够有效减轻NaCl胁迫对菘蓝幼苗生长的影响、提高其体内药用活性成分的含量;总体上看,产自安徽亳州的菘蓝幼苗的耐盐性较强,且不同种源适宜的ALA浓度也有一定差异。     

外源钙离子对小麦幼苗氮素代谢的影响

以普通小麦豫麦34为材料,研究了不同浓度的外源Ca2 对小麦幼苗氮素代谢的影响.在小麦第一片叶完全展开后,开始外源Ca2 处理,设0 (对照)、2、4 mmol · L-1 和8 mmol · L-1 4个Ca2 浓度梯度.处理5d后,测定氮同化酶活性、氮同化量及其它相关代谢物含量.结果表明,小麦幼苗叶片中硝酸还原酶(NR)和谷氨酰胺合成酶(GS)在2 mmol · L-1 Ca2 处理下活性比对照有显著增加,4 mmol · L-1 Ca2 处理的NR活性增加明显,但GS活性增加不显著;8 mmol · L-1 Ca2 处理下NR和GS活性比对照均明显降低.谷氨酸脱氢酶(NADH-GDH)活性在2 mmol · L-1 Ca2 处理下活性增加不明显,而在4、8 mmol · L-1 Ca2 处理下活性显著增加.小麦幼苗氮同化量以4 mmol · L-1处理最大,2 mmol · L-1处理与4 mmol · L-1之间差异不显著;Ca2 浓度为8 mmol · L-1时,氮素同化量明显降低.结果揭示了小麦幼苗不同氮同化途径对Ca2 的响应不同,GS途径比GDH途径对小麦氮素同化量的增加作用更大;4 mmol · L-1对小麦幼苗的氮素利用可能是最有效的Ca2 浓度.     

Pb、Cd单一及复合胁迫对花菖蒲幼苗生长及部分生理指标的影响

采用液体培养法研究了Pb、 Cd单一胁迫及Pb-Cd复合胁迫(500 mg·L-1Pb、 25 mg·L-1Cd、 500 mg·L-1Pb-25 mg·L-1Cd)对花菖蒲(Iris ensata Thunb. var. hortensis Makino et Nemoto)幼苗生长和部分生理指标的影响.结果显示,在500 mg·L-1Pb单一胁迫条件下,花菖蒲幼苗地上部分(叶片)和地下部分(包括根茎和根系)的干质量及耐性指数与对照差异不显著(P>0.05);而在25 mg·L-1Cd单一胁迫和500 mg·L-1Pb-25 mg·L-1Cd复合胁迫条件下,幼苗地上部分和地下部分的干质量及耐性指数显著下降(P<0.05), 其中耐性指数分别仅为0.86和0.79.在500 mg·L-1Pb单一胁迫条件下,叶片中的光合色素(包括叶绿素a、叶绿素b和类胡萝卜素)含量和地下部分的丙二醛(MDA)含量显著高于对照,地上部分的MDA含量显著低于对照,而过氧化物酶(POD)活性则与对照差异不显著;在25 mg·L-1Cd单一胁迫条件下,叶片中的叶绿素a和叶绿素b含量显著低于对照,类胡萝卜素含量和地上部分的MDA含量以及地上部分和地下部分的POD活性均显著高于对照,而地下部分的MDA含量与对照差异不显著;在500 mg·L-1Pb-25 mg·L-1Cd复合胁迫条件下,叶片中的光合色素含量均显著低于对照,地上部分和地下部分的MDA含量和POD活性均显著高于对照,其中MDA含量分别是对照的1.7和2.7倍、POD活性分别是对照的2.5和3.4倍.研究结果表明,花菖蒲幼苗对500 mg·L-1Pb单一胁迫具有一定的耐受性;在复合胁迫条件下Pb和Cd具有协同作用,对花菖蒲幼苗的生长和代谢有显著的抑制作用.     

Hg2+与POD复合处理对小麦萌发及幼苗生长的影响

通过水培实验研究了0、10、20、50、70和100mg·L-1Hg2 和65 U·mL-1的过氧化物酶(POD)混合浸种对小麦(Triticum aestivum L.)萌发及幼苗生长过程中的10个形态和生理生化指标的影响.结果表明:施加外源POD可明显提高种子发芽率、植株日均增重和幼苗叶片的可溶性蛋白含量,增加幼苗叶片内源超氧物歧化酶(SOD)和POD的活性,拈抗Hg2 胁迫对种子发芽率、苗高、日均增重及叶片可溶性蛋白含量的不利影响,Hg2 浓度较高时(≥50mg·L-1),对种子发芽率和日均增重的拮抗作用更明显,并对较低浓度Hg2 (≤20 mg·L-1)胁迫引起的叶片SOD活性的上升和低于100 mg·L-1的Hg2 胁迫引起的叶片POD活性的上升有进一步的促进作用;然而对幼苗平均最长根长度、侧根数和幼苗叶片叶绿素含量则无明显影响.     

Pb-Cu复合胁迫对马蔺幼苗生长和生理指标的影响

采用营养液培养法,研究了不同质量浓度Pb-Cu复合胁迫对马蔺[Iris lactea Pall. var. chinensis (Fisch.)Koidz.]幼苗生长和一些生理指标的影响. 结果表明, 处理35 d后, 在50.00 mg·L-1Pb与0.10、 1.00、 10.00 mg·L-1Cu组成的3个复合胁迫处理组中,马蔺幼苗的株高、根长、地上部分和地下部分的鲜质量和干质量、叶片叶绿素a(Chla)和叶绿素b(Chlb)的含量均低于对照组(0.00 mg·L-1Pb-0.01 mg·L-1Cu),叶片SOD和POD活性则显著高于对照组;其中,50.00 mg·L-1Pb-10.00 mg·L-1Cu处理组幼苗的株高、根长、Chla和Chlb含量及SOD和POD活性均最高,地上部分和地下部分的鲜质量和干质量也较高.在100.00 mg·L-1Pb与0.10、1.00、10.00 mg·L-1Cu组成的3个复合胁迫处理组中,100.00 mg·L-1Pb-0.10 mg·L-1Cu处理组幼苗的株高、根长、地上部分和地下部分的鲜质量及干质量、Chla和Chlb含量以及SOD和POD活性基本上都显著高于对照组,100.00 mg·L-1Pb-1.00 mg·L-1Cu处理组中幼苗的株高、地上部分鲜质量和干质量以及叶片的SOD和POD活性也均显著高于对照组;而在100.00 mg·L-1Pb-10.00 mg·L-1Cu处理组中幼苗的株高、根长以及地上部分和地下部分的鲜质量和干质量均最低,Chla和Chlb的含量则显著低于对照组.研究结果表明, 50.00 mg·L-1Pb与较高质量浓度Cu(10.00 mg·L-1)复合处理可在一定程度上缓解Pb胁迫对马蔺幼苗的伤害;而100.00 mg·L-1Pb与较低质量浓度Cu(0.10 mg·L-1)复合处理不但能减轻Pb胁迫对马蔺幼苗的伤害,还有一定的刺激生长的作用;但较高质量浓度的Pb-Cu复合胁迫则加剧了对马蔺幼苗的生长和生理代谢的抑制作用.     

Pb胁迫条件下狭叶香蒲种子的萌发特性及其幼苗的生理响应

对0、30、150、300、450和600μmol·L-1Pb胁迫条件下狭叶香蒲（TyphaangustifoliaLinn.）种子的萌发特性进行了研究,并分析了0、450、900、1800和2700μmol·L-1Pb胁迫对狭叶香蒲幼苗叶片及根系中部分生理生化指标的影响。结果表明：随Pb浓度提高,狭叶香蒲种子的发芽率、发芽势、发芽指数和活力指数以及下胚轴长度均逐渐下降且低于对照,而其下胚轴长度抑制指数则逐渐增大,但在30μmol·L-1Pb胁迫条件下各项萌发指标均与对照无显著差异。叶片叶绿素a、叶绿素b及总叶绿素含量随Pb浓度提高呈逐渐下降趋势,但在450和900μmol·L-1Pb胁迫条件下与对照无显著差异,而在1800和2700μmol·L-1Pb胁迫条件下显著低于对照。在Pb胁迫条件下叶片和根中SOD活性均显著高于对照但变化趋势不同;随Pb浓度提高,叶片SOD活性呈波动但整体上升的趋势,而根中SOD活性则呈逐渐降低的趋势。叶片和根中POD活性均随Pb浓度提高呈持续上升的趋势,其中,在450和900μmol·L-1Pb胁迫条件下叶片的POD活性低于对照、根的POD活性高于对照,但均与对照无显著差异;而在1800和2700μmol·L-1Pb胁迫条件下叶片和根的POD活性均显著高于对照。在Pb胁迫条件下叶片和根中AsA和MDA含量均高于对照。随Pb浓度提高,叶片的AsA含量总体上逐渐增加但在450和900μmol·L-1Pb胁迫条件下与对照无显著差异;而根的AsA含量则呈先增加后降低的趋势且均与对照差异显著。随Pb浓度提高,叶片的MDA含量先增后降但均与对照无显著差异;而根的MDA含量呈“高-低-高”的波动趋势且仅在450μmol·L-1Pb胁迫条件下与对照差异显著。综合分析结果显示：狭叶香蒲幼苗根系对Pb胁迫的敏感性可能强于叶片;狭叶香蒲种子可在轻度Pb污染水体中萌发和生长;其幼苗对Pb胁迫具有一定的耐性,可用于中度Pb污染水体的修复。     

施肥对香樟幼苗生长及养分分配的影响

施肥是苗木培育的重要方式,香樟是乡土珍稀阔叶树种,苗木培育对乡土珍稀树种的保护、繁育、推广具有极其重要的作用,施肥对苗木的生长和发育具有重要的影响。因此,为了探讨香樟幼苗生长及植物体内养分分配对施肥的响应,该研究采用正交设计,设置了氮、磷、钾3因素3水平(N、P:0、3、6 g·株-1;K:0、2、4g·株-1),对盆栽香樟幼苗进行指数施肥。结果表明:(1)氮肥对香樟幼苗苗高、地径、生物量的影响最为显著,磷肥和钾肥的影响则较小;(2)氮素在香樟幼苗叶、茎、根中的分布状况主要受氮肥的影响,磷素在香樟幼苗叶、茎、根中的分布状况主要受氮肥和磷肥的影响,钾素在香樟幼苗叶、茎、根中的分布状况主要受钾肥的影响;(3)香樟幼苗的苗高生长与叶片氮含量、叶片磷含量呈显著正相关(P0.05),地径生长与茎氮含量呈显著正相关(P0.05),叶生物量与叶片氮含量、叶片磷含量呈显著正相关(P0.05),茎生物量与叶片磷含量呈显著正相关(P0.05);(4)综合分析得出,对香樟幼苗苗高、地径生长,以及枝叶生物量积累最具促进作用的施肥水平为氮肥(6 g·株-1)、磷肥(6 g·株-1)、钾肥(4 g·株-1)。     

山核桃外果皮黄酮提取液对小麦和绿豆幼苗的化感效应

以盆栽小麦和绿豆幼苗为材料,研究了7个浓度山核桃外果皮黄酮提取液(0.02～0.14 mg·L-1)处理对小麦和绿豆幼苗生长及其叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性、氧自由基(O2)、丙二醛(MDA)含量、相对电导率的影响.结果显示:在试验浓度范围内,各处理对小麦和绿豆生长具有促进作用;0.06～0.08 mg·L-1黄酮提取液对小麦苗高和根长的影响极显著(P<0.01),0.06 mg·L-1时根长和苗高的化感效应指数(RI)分别为0.136和0.120;0.12 mg·L-1黄酮提取液对绿豆胚根和胚轴具有极显著促进作用,对下胚轴和胚根的化感效应指数分别为0.147和0.123;适宜浓度黄酮提取液能显著提高小麦和绿豆幼苗叶片SOD、POD的活性,同时显著降低其O2产生速率、MDA含量和相对电导率.研究表明,适宜浓度的山核桃外果皮黄酮提取液具有促使小麦和绿豆幼苗生长、提高其叶片保护酶活性和增强细胞膜结构稳定性的作用.     

Hg2+ 与POD 复合处理对小麦萌发及幼苗生长的影响

通过水培实验研究了0、10、20、50、70和100 mg.L-1 Hg2+和65 U.mL-1的过氧化物酶(POD)混合浸种对小麦(Triticum aestivum L.)萌发及幼苗生长过程中的10个形态和生理生化指标的影响。结果表明：施加外源POD可明显提高种子发芽率、植株日均增重和幼苗叶片的可溶性蛋白含量,增加幼苗叶片内源超氧物歧化酶(SOD)和POD的活性,拮抗Hg2+胁迫对种子发芽率、苗高、日均增重及叶片可溶性蛋白含量的不利影响,Hg2+浓度较高时(≥50 mg.L-1),对种子发芽率和日均增重的拮抗作用更明显,并对较低浓度Hg2+(≤20 mg.L-1)胁迫引起的叶片SOD活性的上升和低于100 mg.L-1的Hg2+胁迫引起的叶片 POD活性的上升有进一步的促进作用;然而对幼苗平均最长根长度、侧根数和幼苗叶片叶绿素含量则无明显影响。     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Analysis of twin of eyeless regulation during early embryogenesis in Drosophila melanogaster

The Drosophila Pax6 homolog twin of eyeless (toy) is so far the first zygotically expressed gene involved in eye morphogenesis in Drosophila. The study of its expression during embryogenesis is therefore informative of the initial events of eye development in Drosophila. We have analyzed how the initial expression domain of toy at cellular blastoderm is regulated. We show that the three maternal patterning systems active in the cephalic region (the anterior, terminal and dorsal-ventral systems) cooperate with zygotically activated gap genes to shape the initial expression domain of toy. Whereas Bicoid, Dorsal and Torso signaling synergistically act as activators, Hunchback, Knirps and Decapentaplegic act as repressors.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

广西青藓科分类学修订

通过对采自广西24个县(市)的1 147份青藓科植物标本的逐一鉴定及相关文献的查阅,确认有广西青藓科植物11属、44种,其中包括广西青藓科植物新记录属1属,即拟异叶藓属(Pseudokindbergia),新记录种7种,分别为匐枝青藓(Brachythecium procumbens)、阔叶尖喙藓(Oxyrrhynchium latifolium)、泛生尖喙藓(O. vagans)、拟异叶藓(Pseudokindbergia dumosa)、华东细喙藓(Rhynchostegiella sinensis)、长肋拟青藓(Sciurohypnum populeum)和弯叶拟青藓(S. reflexum)。该文提供了修订后的广西青藓科植物名录,并对其中的新记录属、种的主要形态学识别特征、生境和地理分布等进行了详细描述。     

Host plants of someRhinanthoideae (Scrophulariaceae) of eastern North America

Twenty three species in 11 genera were examined in the field to determine hosts. OnlyStriga asiatica andSeymeria cassioides have a narrow host range being restricted to grasses and pines, respectively. These are the only species which cause pronounced and sometimes serious host damage. The other species attach to a great diversity of hosts.     

Evaluation of antiprotozoal and antimycobacterial activities of the resin glycosides and the other metabolites of Scrophularia cryptophila

Resin glycosides are secondary metabolites exclusive to the convolvulaceous plants. In this study, crypthophilic acids A–C (1–3), the first resin glycosides occurring in another family (Scrophulariaceae), and the other constituents of Scrophularia cryptophila were examined for in vitro antiprotozoal and antimycobacterial potentials. Except for crypthophilic acid B (2), all tested compounds exhibited growth-inhibitory effect against Trypanosoma brucei rhodesiense, with l-tryptophan (6) and buddlejasaponin III (7) being the most potent ones (IC₅₀'s 4.1 and 9.7 μg/ml). In contrast, the activity towards Trypanosoma cruzi was poor, and only crypthophilic acid C (3), 6 and 7 were trypanocidal at concentrations above 40 μg/ml. With the exception of 2 and 6, all compounds were active against Leishmania donovani. Harpagide (4) and 3 emerged as the best leishmanicidal agents (IC₅₀'s 2.0 and 5.8 μg/ml). Only compounds 3, 6 and 7 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.2, 16.6 and 22.4 μg/ml. Overall the best and broadest spectrum activity was presented by compounds 3 and 7, as they inhibited all four parasitic protozoa. None of the isolates had significant activity against Mycobacterium tuberculosis (MICs >100 μg/ml) or were toxic towards mammalian (L6) cells. This is the first report of antiprotozoal activity for natural resin glycosides, as well as for harpagide (4), acetylharpagide (5), tryptophan (6) and buddlejasaponin III (7).     

Apoptotic Regulation of Caspase Activity

Intracellular cysteine aspartate-specific proteases (caspases) play both signaling and effector roles in realizing the program of cell death. Caspases function as proteolytic cascades unique for each cell type and signal triggering apoptosis. All parts of the proteolytic cascades are duplicated and controlled by feedback signals. Amplification cycles between pairs of caspases (the third and the sixth, the ninth and the third, the twelfth and the sixth, and others) help multiply the initial apoptotic signal. The presence of physiological inhibitors of apoptosis that directly interact with caspases creates a multilevel regulatory network of apoptosis in cell. The caspase proteolytic cascades are also regulated by sphingolipid secondary messengers, among them ceramide, sphingosine, and their phosphates. Moreover, an association of the caspase signaling with ubiquitin-dependent proteolysis is shown in cells. In particular, the use of extracellular activators and inhibitors of caspases allows irreversible activation of apoptosis in tumor cells or the prevention of apoptosis in cortical neurons under neurodegenerative diseases.     

The effect of cyanobacteria and azolla on the performance of rice under different levels of fertilizer nitrogen

Cyanobacteria and/or azolla were inoculated, with urea at 0, 72 or 144 kg N/ha, in plots in which azolla-free Indica rice var. IR 28 was grown. Productive tillers, yield and nitrogen contents of grain and straw positively responded to inoculation with cyanobacteria or azolla, even with fertilizer-N up to 144 kg N/ha. Inoculation improved colonization by cyanobacteria. Azolla were superior to the asymbiotic cyanobacteria in enhancing rice performance. Urea at a rate of 72 kg N/ha was found to support the best colonizations when applied with cyanobacteria or azolla or, to give maximum rice yields, both inoculants.