邻羟基苯甲酸对不同化感型杉木无性系抗氧化酶活性的化感效应

自毒作用是导致杉木人工林连栽地力衰退、生产力下降的主要原因之一,邻羟基苯甲酸是杉木主要自毒物质之一。以筛选的自毒物质忍耐型杉木无性系(01号)和自毒物质敏感型杉木无性系(02号)组培苗为试验材料,分析邻羟基苯甲酸对2个不同化感型杉木无性系抗氧化酶活性的化感效应,以期为解决杉木连栽障碍提供一条新的生物途径。研究结果表明,邻羟基苯甲酸各胁迫浓度对不同化感型杉木无性系SOD活性的化感效应在胁迫10d、20d表现为促进效应,胁迫30d转变为抑制效应;2个不同化感型杉木无性系SOD活性化感效应的差异主要从胁迫20d开始,01号在胁迫20d促进效应大于02号,30d的抑制效应明显小于02号。各胁迫浓度对2个不同化感型杉木无性系叶片POD及AsA-POD活性的化感效应均表现为促进效应;胁迫第10d、20d时,各胁迫浓度对01号无性系POD活性的促进效应明显大于02号;01号无性系在受到胁迫后AsA-POD活性迅速增强,并在长时间胁迫后仍维持比02号无性系更高的活性;01号无性系PPO活性在各胁迫浓度下均表现为促进效应,而02号无性系则随胁迫时间的延长表现为抑制-促进-抑制的变化特点。     

邻羟基苯甲酸对干旱胁迫下杉木幼苗保护酶的影响

为研究干旱胁迫下杉木自毒物质邻羟基苯甲酸(SA)对杉木幼苗的毒害作用,采用不同浓度的聚乙二醇(PEG-6000)模拟干旱处理,通过水培方法研究干旱胁迫下不同浓度杉木自毒物质邻羟基苯甲酸(SA)对杉木幼苗保护酶的影响.结果表明:在轻度(-0.3MPa)、中度(-0.5MPa)干旱胁迫下,随SA浓度增加超氧化物歧化酶(SOD)活性先降后升再下降,但重度(-0.7MPa)干旱胁迫下,SOD活性直线下降;过氧化物酶(POD)活性则表现为在轻度干旱胁迫下先降后升,中度和重度干旱胁迫下总体呈下降趋势.     

田间旱育条件下不同化感潜力水稻的抑草效应分析

研究了田间旱育条件下, 在土壤水分充足和适度干旱状态时, 化感水稻"PI312777"和非化感水稻"Lemont"的抑草效应差异.结果表明, 在两种供水状态下, 化感水稻"PI312777"对田间杂草的控制效应显著高于非化感水稻"Lemont","PI312777"对各种杂草抑制效应指数的绝对值多在0.5以上, 而"Lemont"对各种杂草抑制效应指数的绝对值则多在0.5以下.进一步分析发现, 适度干旱胁迫下"PI312777"和"Lemont"对杂草的抑制效应都有增强趋势, 且"PI312777"稻田杂草生物量的降低幅度高于"Lemont"稻田; 以与非化感水稻"Lemont"共生下的杂草生物量为对照, 化感水稻"PI312777"对稻田杂草均表现出一定的化感抑制作用, 且适度干旱胁迫诱导下化感作用强度进一步增加.此外, 水稻对不同杂草的生物干扰强度不同, 化感水稻"PI312777"对夏熟稻田阔叶杂草有较强的控制效果, 干旱胁迫诱导"PI312777"对无芒稗(Echinochloa crusgalli L.)的化感潜力明显增强.     

化感物质对小麦幼苗吸收氮的影响

实验研究了3种不同浓度化感物质阿魏酸(FA)、苯甲醛(BH)、4-对叔丁基苯甲酸(4-BA)对小麦幼苗吸收NO₃-N和NH₄-N的影响 结果表明,小麦幼苗对NO₃-N和NH₄-N吸收随化感物质浓度增大而逐渐降低。15d时在高浓度(0．5g／L)化感物质下小麦幼苗对NO₃-N吸收,FA、BH、4-BA处理分别为对照的58%、5O%、53％;对NH₄-N的吸收分别为对照的42%、19%、33%。对NH₄-N 吸收的抑制作用太于对NO₃-N吸收的抑制。化感物质对小麦幼苗吸收氮(N)的影响主要表现在小麦幼苗生长的前15d,30d时各浓度化感作用强度均大为减弱。     

化感物质对土壤硝化反应影响的研究

研究了４种化感物质硝化反应的影响，试验结果表明，化感物质能减少ＮＨ＾＋４向ＮＯ３＾－氧化，且高浓度比低浓度效果显著。４种化感物质的硝化抑制顺序为：阿巍〉对叔丁基苯甲酸〉对羟基苯甲酸〉苯甲酸。不同的温度和肥料可影响化感物质的硝化抑制作用。     

低氮胁迫下小麦抑草作用的化感效应与资源竞争分析

化感效应和资源竞争在作物抑草中起重要作用。为区分低氮胁迫下小麦抑草作用的化感效应与资源竞争,以强化感小麦品种‘115/青海麦’、‘92L89’和弱化感小麦‘抗10103’为材料,设置氮水平为25 mg·L-1、50mg·L-1、100 mg·L-1和200 mg·L-1的水培试验,通过小麦与看麦娘共培、应用含小麦根系分泌物的小麦-看麦娘共培液处理看麦娘,分别测定了小麦对看麦娘的生物干扰作用、化感效应及资源竞争效应。结果表明,不同化感潜力的小麦对看麦娘的抑制能力存在显著差异,抑制率大小为‘115/青海麦’(55.1%~73.9%)‘92L89’(48.9%~65.9%)‘抗10103’(15.4%~45.5%),且抑制率随氮水平的降低而增大。在小麦的抑草作用中,化感效应与资源竞争并存。低氮胁迫条件下,强化感小麦抑草能力增强主要通过提高化感效应实现;弱化感小麦抑草能力增强主要通过提高资源竞争实现。不同化感潜力小麦的抑草作用在低氮胁迫下表现出不同的生态策略。小麦抑草作用的化感效应均随氮水平降低而增大,其抑制率随氮水平的变化可用一元二次方程加以拟合。     

田间旱育条件下不同化感潜力水稻根际土壤酚酸类和萜类物质分析

酚酸类和萜类是水稻化感作用研究中研究较多、争议较大的2大类化感物质,但目前有关水稻根系分泌物的研究多在实验室条件下进行。本文以国际公认的强化感水稻‘PI312777’和弱化感水稻‘Lemont’为材料,以未种植水稻的土壤为对照,研究了其在田间旱育条件下,不同土壤水分状态(旱地和湿地)时,根际土壤酚酸类和萜类物质的差异。结果表明,不同水分条件下不同化感潜力水稻品种和对照根际土壤中酚酸类物质和萜类物质的组成较为相似,但各物质含量存在一定差异。适度旱胁迫下,各处理根际土壤中所检测到的咖啡酸、对羟基苯甲酸、香草酸、阿魏酸和肉桂酸5种酚酸类物质及总量均有提高,其中强化感水稻‘PI312777’根际土壤中5种酚酸类物质提高最显著,比CK湿地处理提高2.84倍;在各处理根际土壤共检测到的27种萜类物质中,17种是含氧单萜;干旱胁迫导致各处理根际土壤单萜烯、含氧单萜、含氧倍半萜和总萜变化程度和变化趋势不同,单萜烯相对含量在强化感水稻‘PI312777’根际土壤中明显提高,而在弱化感水稻‘Lemont’和对照根际土壤中则降低。本文在此基础上讨论了由此导致2种水稻田间化感抑草效果差异的原因与机制。     

营养胁迫下邻羟基苯甲酸对杉木幼苗保护酶的影响

通过水培方法研究了营养胁迫下不同浓度杉木自毒物质邻羟基苯甲酸(Salicylic Acid,SA)对杉木幼苗SOD和POD的影响.结果表明:在不同营养胁迫(完全营养液、缺钙营养液、缺磷营养液)下,随浓度变化,SA对1年生杉木幼苗具有不同程度毒害作用.与3个对照(不含SA的3个梯度营养胁迫)相比,缺钙或缺磷胁迫下,低浓度SA(50 mg·L-1)处理1年生杉木幼苗的SOD、POD等指标总体上表现为先降低后上升趋势;较高浓度(100 mg·L-1)和高浓度(200 mg·L-1)SA处理的1年生杉木幼苗SOD、POD总体上表现为递减趋势.     

化感物质对土壤硝化作用的影响

试验研究了3种化感物质－苯甲酸、对羟基苯甲酸和阿魏酸在3种浓度（0.5mmoL、2.5mmoL和5.0mmol）、不同pH、不同土壤含水量等环境因子作用下对土壤硝化作用的影响,在第1d、4d、7d、10d、14d取样与对照比较,测定其对土壤中NH4^ -N转化为NO3^--N过程中的影响。结果表明,阿魏酸和苯甲酸对硝化作用的抑制率略高于对羟基苯甲酸,且阿魏酸随浓度升高而抑制作用加强。研究所采用的2种不同pH的土壤未表现出明显的差异;不同土壤含水量对转化为NO3^--N的总量影响较大,不加水的土壤样品NO3^--N的转化量很少,且随时间的推移其总量无多大为变化,而饱和含水量的样品NO3^--N的转化量随时间的推迟其总量一直上升,说明水分对土壤中NO3^--N的转化起着非常重要的作用。     

化感物质阿魏酸对小麦幼苗内源激素水平的影响

研究了化感物质阿魏酸（FA）在0.25mmol/L、2.50mmol/L浓度下对小麦幼苗内源激素-生长素（IAA）、赤霉素（GA）、细胞分裂素（ZR）和脱落酸（ABA）含量的影响,并测定了培养液中剩余阿魏酸量,结果表明,在2.50mmol/L处理的培养液中剩余阿魏酸量在3-10d内下降最快,14d后98%以上阿魏酸消失。不同浓度阿魏酸对小麦幼苗中4种内源激素的含量表现为0.25mmol/L与对照差别不大,2.50mmol/L样品中的含量均呈上升趋势,但生长素、赤霉素、细胞分裂素在小麦体内大量积累,反而抑制了小麦幼苗的生长,同时诱导脱落酸含量升高。     

CHANGES IN ENDOGENOUS HORMONAL STATUS IN CORN (ZEA MAYS) HYBRIDS UNDER DROUGHT STRESS

Corn has several mechanisms that allow it to perceive the incoming water deficit and rapidly regulate its growth and physiology to cope with this stress. Among these regulated physiological responses, phytohormones, such as abscisic acid (ABA), gibberellin (GA₃), indole acetic acid (IAA), and zeatin (ZT) have important roles. To evaluate changes in hormonal status of corn hybrids under different drought stress levels, a greenhouse study was conducted at the College of Agriculture, Shiraz University, Iran, during summer 2010. Treatments consisted of drought stress in five levels: 100% field capacity (F.C.) as control, 80, 60, 40, and 20% F.C. and three corn hybrids, including single cross 704 (SC704), Maxima, and double cross 370 (DC370). Results showed that drought stress significantly affected phytohormones concentration, ABA concentration was increased and GA₃, IAA and ZT concentrations were decreased. Indeed, there was an initial increase (about 13.5% more than control) in IAA concentration. In severe drought condition, ABA concentration was eventually decreased (37.8% less than the first drought level, i.e., 80% F.C.). The ratios of GA₃, IAA and ZT to ABA concentration were also decreased. Among hybrids, SC704 showed the highest phytohormone concentrations and DC370 had the highest ratios of GA₃, IAA, and ZT to ABA concentrations. Overall, the results of this study suggest that although mild drought stress was associated with greater ABA concentration, it had negative impact on GA₃, IAA, and ZT concentrations. Furthermore, SC704 hybrid appeared to be more resistant to drought stress than the other hybrids.     

Relationship Between Iron Deficiency Stress and Endogenous Hormones in Iron-Efficient versus Inefficient Apple Genotypes

In solution culture at different iron (Fe) concentrations, both contents of endogenous hormones or the IAA oxidase activities in the roots and the diffusive IAA contents in the stem apex were analyzed for Malus xiaojinensis (an Fe-efficient apple genotype) or M. baccata (an Fe-inefficient apple genotype). The results showed that higher amounts of IAA in M. xiaojinensis were transported from the stem apex into roots under Fe deficiency stress, which resulted in a great enhancement of the root IAA content, being 4–5 times higher at Fe deficiency than at a normal Fe level. Root IAA content of M. baccata did not show any obvious change at both deficiency and normal level of Fe. When the appearance of leaf chlorosis was used as the test point by the time, there was no remarked difference in fluctuation of the root GA₃ or ABA contents between M. xiaojinensis and M. baccata, although the developing trends of the root GA₃ or ABA contents were slightly lagging for M. xiaojinensis. The results obtained in this experiment suggested that IAA might be a signal factor of inducing Fe deficiency response in plant of genus Malus.     

不同氮素形态对干旱胁迫杉木幼苗养分吸收及分配的影响

【目的】干旱胁迫是限制植物生长的重要非生物因素之一,而适宜的氮素营养可以提高植物的抗旱性。本文探讨了供应不同形态氮源对干旱条件下杉木[Cunninghamia lanceolata (Lamb.) Hook]幼苗养分吸收及分配的影响。【方法】采用水培试验,供试杉木材料为2个无性系幼苗(7–14号和8–8号),在营养液中添加10%(w/v)PEG-6000进行干旱胁迫。营养液中的氮源处理包括硝态氮、铵态氮、硝铵混合氮,氮素浓度均为4.571mmol/L,每个品种均设6个处理。培养20天后,测定了杉木幼苗根、茎、叶的养分含量及生物量。【结果】与正常水分供应相比较,干旱胁迫条件下供应铵态氮可促进叶片N、K以及茎叶P、K的吸收,供应混合氮可促进根部K的吸收;供应铵态氮可促进根、茎对Ca的吸收,对叶片Ca无明显作用。干旱胁迫对根部Fe、Mn、Cu、Zn吸收量影响显著,氮素供应不同程度地降低了干旱胁迫下各器官Mg、Fe、Mn和Cu吸收量,表现为抑制吸收,但添加铵态氮比硝态氮的降低幅度小。3个氮源处理均降低了干旱条件下根部Zn吸收量,但没有降低甚至增加了茎、叶中Zn的吸收量,说明氮营养可调节Zn在各器官间的分配,缓解干旱导致的缺锌现象。不同器官之间各养分吸收量差异显著,3个氮源处理中,N和P吸收量表现为叶>根>茎,K和Ca为叶>茎>根,Fe、Cu为根>叶>茎,Mg、Mn和Zn在各器官之间的分配规律不一。铵态氮吸收量均表现为叶>根>茎,且各器官铵态氮吸收量显著高于硝态氮,说明杉木具有明显的喜铵特性。【结论】在干旱胁迫下,氮素供应形态显著影响杉木幼苗对养分的吸收及在各器官中的分配,作用效果因家系品种和元素种类而异。总体来讲,铵态氮提高干旱胁迫下杉木幼苗养分吸收的效果好于硝态氮,杉木可以认为是喜铵植物。     

杉木紫色酸性磷酸酶基因ClPAP18b的克隆及表达分析

  【目的】  以速生丰产型杉木无性系洋023、洋036、洋6421和拟南芥为材料,研究杉木中紫色酸性磷酸酶 (PAPs) 的功能作用,以筛选具有磷素高效利用特性的杉木无性系。  【方法】  采用PCR技术克隆PAP18b基因,分析其序列特征和同源性,并对杉木无性系洋023、洋036、洋6421进行正常供磷 (1.0 mmol/L KH₂PO₄) 和低磷胁迫 (0.1 mmol/L KH₂PO₄,0.9 mmol/L KCl) 砂培盆栽处理0、10、15、30和60天,测定酸性磷酸酶活性及全磷含量,定量分析根和叶中ClPAP18b基因表达量、磷含量及酸性磷酸酶活性的关系,并将ClPAP18b基因过表达至拟南芥,进行该基因的功能验证。  【结果】  成功克隆获得杉木PAP18b基因CDS序列 (1 212 bp),命名为ClPAP18b,该基因编码404个氨基酸,亚细胞定位于胞间区,这表明ClPAP18b基因可能发挥调控酸性磷酸酶分泌至胞外的功能。酸性磷酸酶活性测定结果表明,30天磷处理后,正常供磷和低磷处理下,杉木洋036和洋6421无性系根中的酸性磷酸酶活性均高于叶,而根中酸性磷酸酶活性低磷处理下高于正常供磷处理;洋023的根和叶中酸性磷酸酶活性在低磷胁迫诱导下多高于正常供磷条件下根和叶中酸性磷酸酶活性。磷含量分析结果表明,杉木洋023、洋036和洋6421无性系的地上部磷含量高于地下部,不同水平供磷处理后,不同杉木无性系或同一杉木不同组织磷含量存在差异。RT-qPCR 结果显示,低磷胁迫诱导杉木ClPAP18b基因表达。低磷条件下,ClPAP18b过表达拟南芥植株长势优于对照组,且过表达植株中的酸性磷酸酶活性叶高于对照组,但花青素积累量低于对照组。此外,相比于正常供磷处理植株,过表达ClPAP18b拟南芥中PHT1; 2、PHT1; 8和AtPAP26等与磷胁迫相关的基因表达量显著高于对照组,而AtPAP12和AtPAP17基因表达量明显降低。  【结论】  低磷胁迫诱导杉木ClPAP18b基因表达和酸性磷酸酶活性增强,但不同杉木无性系对磷缺乏的适应性存在明显差异,过表达ClPAP18b基因可促进拟南芥植株耐低磷胁迫,ClPAP18b基因可能在杉木低磷胁迫调节机制中发挥调控作用,可作为改良杉木耐低磷的重要候选基因。     

外源GA3对高原夏季胡萝卜肉质根发育的影响

为了揭示外源GA3对胡萝卜肉质根发育的影响机理,并为高原夏季胡萝卜安全高效栽培技术研究提供参考理论,本试验以耐先期抽薹的胡萝卜品种为试材,采用酶联免疫吸附法(ELISA),研究了外源GA3对高原夏季胡萝卜肉质根膨大、木质化及其内源激素含量的影响。结果表明,在叶片旺盛生长期和肉质根迅速膨大期分别喷施5.78×10-4 mol·L-1外源GA3 1次,或在苗期、叶片旺盛生长期和肉质根迅速膨大期喷施5.78×10-4 mol·L-1外源GA3 1~3次,能显著降低高原夏季胡萝卜苗期肉质根日鲜重增长速率与库活力,促进肉质根木质化。与对照相比,喷施外源GA3,可显著降低苗期肉质根内源GA3、IAA、GA4、ABA、DHZR与IPA含量,显著提高肉质根内源ZR含量;显著降低叶片旺盛生长期肉质根内源GA3、IAA、GA4、IPA含量,显著提高内源ZR含量;显著提高迅速膨大期肉质根内源IAA、GA4、ZR含量;显著降低肉质根迅速膨大期之前的IAA/ZR和GA4/ZR比值。随着外源GA3喷施次数的增多,IAA/ZR和GA4/ZR比值在肉质根迅速膨大期有逐渐增高的趋势。外源GA3通过改变内源激素含量及其平衡状态来影响高原夏季胡萝卜肉质根的发育。     

Roles of glycine betaine in mitigating deleterious effect of salt stress on lettuce (Lactuca sativa L.)

This study was conducted to evaluate the roles of glycine betaine (GB) in mitigating deleterious effect of salt stress on lettuce. Lettuce plants were subjected to two salinity (0 and 100 mmol l^?1 NaCl) and four GB levels (0, 5, 10, 25 mmol l^?1). Salinity resulted in a remarkable decrease in growth parameters, relative leaf water content and stomatal conductance. Plants subjected to salt stress exhibited an increase in membrane permeability (MP), lipid peroxidation (MDA), leaf chlorophyll reading value, H₂O₂ and sugar content. Exogenous foliar applications of GB reduced MP, MDA and H₂O₂ content in salt-stressed lettuce plants. Salt stress increased Na and generally decreased other nutrient elements. GB reduced Na accumulation, but significantly increased other element contents under salinity conditions. The study showed that gibberellic acid (GA) and salicylic acid (SA) content in salt-stressed plants were lower than those of nonstressed plants. However, salinity conditions generally increased the abscisic acid content. GB treatments elevated the concentrations of GA, SA and indole acetic acid (IAA) at especially 10 and 25 mmol l^?1 GB under salt stress conditions. It could be concluded that exogenous GB applications could ameliorate the harmful effects of salt stress in lettuce.     

Identifizierung und Bestimmung einiger Gibberelline und der Einfluß von Chlorcholinchlorid (CCC) auf das Gibberellinspektrum der einzelnen Getreidearten

Identification and determination of some gibberellins in the gibberellin spectrum of some cereals, als affected by CCC treatment The gibberellin contents of wheat, barley and oat plants, treated with CCC, were studied during the vegetative period. It was possible to identify a characteristic gibberellin spectrum for every cereal plant examined, although the variation was in a limited number of gibberellin forms. A great variation in the content of individual gibberellic acid forms was noticed, as well, among the different cereals studied. The highest content of gibberellins was found with GA₃. The content of GA₅ was lower than that of GA₉ while was not generally higher than that of GA₈. CCC-treated cereal plants showed lower values of gibberellins when compared with those of control. On the other hand, CCC treatment did not affect the content of gibberellins in the spikes which showed a considerably high content of GA₃, GA₅ and GA₉. A higher content of GA₇ was observed in both barley and oats, but not in the case of wheat, during tillering stage. However it was difficult, from the results of the present work, to indicate whether GA₇ is reponsible for the week effect of CCC obtained with both barley and oats or not.     

不同林龄杉木林下套种阔叶树对土壤磷组分的影响

套种是杉木人工林经营的重要措施,磷是南方森林生态系统中主要限制性养分元素之一,但套种模式对土壤磷素的影响尚不明确。以亚热带杉木人工林表层(0-10 cm)土壤为对象,研究套种林(杉阔套种幼林、杉阔套种成熟林)和杉木幼林土壤理化性质和土壤各形态磷含量差异,分析套种对杉木人工林土壤磷含量的影响。结果表明:(1)不同套种林显著改变土壤总磷、土壤总无机磷、土壤总有机磷、土壤微生物生物量磷(MBP)和土壤酸性磷酸酶活性(APA),大小顺序均为杉阔套种成熟林>杉阔套种幼林>杉木幼林。(2)土壤各磷组分中活性磷含量较低,其中NaHCO3-Po在活性组分中占主导;土壤NaOH-Po是中等活性磷的主要组分,杉阔套种成熟林尤为显著;闭蓄态磷(Residual-P)在总磷含量中最高。(3)与杉木幼林相比,杉阔套种成熟林显著增加了树脂提取态磷(Resin-Pi)、碳酸氢钠提取态有机和无机磷(NaHCO3-Pi、NaHCO3-Po)、氢氧化钠提取态有机和无机磷(NaOH-Pi、NaOH-Po)、氢氧化钠残留提取态有机磷(NaOHu.s-Po)、盐酸提取态磷(HCl-Pi)和闭蓄态磷(Residual-P)含量;土壤总无机磷、NaHCO3-Po、HCl-Pi、NaHCO3-Pi、NaOHu.s-Pi和Residual-P对杉阔套种幼林的响应不敏感。(4)除含水率外不同林龄下杉阔套种林土壤磷形态与土壤理化性质(土壤总碳氮、土壤可溶性有机氮、土壤微生物生物量磷、酸性磷酸酶)呈正相关性(P<0.05)。冗余分析表明,土壤磷组分的变化主要受MBP调控,且MBP与有机磷组分(NaOHu.s-Po、NaOH-Po)和HCI-Pi呈显著正相关。总之,套种林的土壤磷素有效性高于杉木幼林,土壤养分状况更佳。     

Calcium deficiency and gibberellic acid enhance susceptibility of pumpkin and sunflower seedlings to Sclerotinia sclerotiorum infection

Pumpkin (Cucurbita pepo L.) and sunflower (Helianthus annuus L.) seedlings were grown in culture deficient in calcium and inoculated with Sclerotinia sclerotiorum (Lib.) de Bary. Three days after inoculation the seedlings showed a susceptibility to the pathogen that was inversely proportional to the calcium content of the nutrient solution. Plants treated with gibberellic acid (GA₃) became more susceptible to infection by S. sclerotiorum. Increased addition of GA₃ resulted in increases in infection both in rate and severity. Sunflower was more susceptible to the pathogen than was pumpkin. GA₃ treatment consistently decreased the calcium content in both species. The effect of calcium deficiency on infection by S. sclerotiorum was greatly amplified by GA₃ addition.