农杆菌共培养条件对小麦种子萌发和幼苗生理生化特性的影响

以‘郑9023’、‘中13’和‘西农1376’3个小麦品种(系)为主区,再分别以农杆菌共培养时间、共培养温度以及乙酰丁香酮(AS)浓度为副区,对农杆菌浸种处理后小麦种子萌发及幼苗生理生化特性进行了研究。结果表明,各小麦品种(系)与共培养时间、共培养温度以及AS浓度的互作效应不显著;随共培养时间的延长,小麦种子发芽率、幼苗株高、鲜重、叶绿素含量呈下降趋势,MDA含量、白化苗率、卡那霉素抗性苗率则呈上升趋势,而POD活性则呈先升后降的趋势,农杆菌对小麦种子及幼苗的伤害随共培养时间的延长而增大,且当共培养时间超过2 d时其伤害作用更为明显;共培养温度为25℃时,小麦种子发芽率、幼苗株高、鲜重、叶绿素含量达到或接近最低值,POD活性、MDA含量、白化苗率则达到最大值,此时农杆菌对小麦种子及幼苗不利影响最为明显;加入AS能促进农杆菌对小麦的侵染效果,并以150μmol/L AS的促进作用最强,对小麦种子萌发及幼苗生理生化指标的影响也最大;小麦不同品种(系)对农杆菌的反应存在一定基因型差异。依据共培养条件下小麦种子萌发和幼苗生理生化特性及卡那霉素抗性苗率综合分析认为,农杆菌浸种法转化小麦时较适宜的条件为:共培养时间应控制在2～3 d、共培养温度22～25℃、AS浓度为150μmol/L。     

壳聚糖包衣对油菜种子萌发及幼苗耐盐性影响

以不同浓度的壳聚糖对油菜种子进行包衣处理,考察其对油菜种子萌发及幼苗耐盐性的影响,并在不同盐浓度胁迫条件下对种子萌发时的发芽势、发芽率、生物量（鲜重、干重、根长、芽长）等指标进行测定,同时分析油菜幼苗叶绿素含量、可溶性蛋白及可溶性糖含量的变化。结果表明,一定浓度的壳聚糖包衣处理可提高油菜种子发芽率、发芽势、生物量、幼苗的耐盐指数、叶绿素含量、可溶性蛋白及可溶性糖的含量,其中浓度为0.25 g·L^-1壳聚糖包衣处理对油菜种子萌发的促进效果较好,而浓度为0.50 g·L^-1壳聚糖包衣处理对提高油菜幼苗耐盐性具有较好的促进作用。     

EMS处理对小麦种子萌发和幼苗生长的影响

甲基磺酸乙酯(EMS)是一种常用的诱变剂,在作物诱变育种上应用广泛。EMS在诱变种子的同时也是一种非生物胁迫,能显著降低种子的发芽率。该实验以小麦‘扬麦15’种子为实验材料,设置了7个EMS浓度处理梯度(0%、0.6%、0.8%、1.0%、1.2%、1.4%和1.6%),每个浓度设置3个处理时间(10 h、12 h、14 h),在种子萌发后测定发芽势和发芽率,并对种子进行生物量测定和形态结构观察,探讨EMS处理对小麦种子萌发和幼苗生长的影响机制。结果表明：(1)随着EMS浓度的提高和处理时间的延长,小麦种子的萌发率逐渐降低;幼苗的生长逐渐变得缓慢,根长和叶长明显变短。(2)随着EMS处理浓度的升高和处理时间的延长,小麦种子胚乳内淀粉体的降解速率变缓。(3)同一处理时间下,EMS的浓度越高,小麦根系越短,根部横截面积、维管束面积以及皮层面积也越小。研究发现,EMS处理会明显降低小麦种子的发芽率,减缓种子贮藏物质的降解速度,抑制小麦根系的生长。     

壳聚糖包衣对油菜种子萌发和幼苗生长以及几个生理生化指标的影响

不同酸溶剂与不同分子量壳聚糖包衣均促进油菜种子萌发和幼苗生长。其中壳聚糖无机酸溶剂包衣种子发芽率及幼苗生化等指标优于有机酸溶剂 ;小分子量壳聚糖包衣优于大、中分子量的。壳聚糖包衣处理有促进植物生长之功能     

磺胺对小麦种子萌发和幼苗生长的影响

初步探讨了磺胺对小麦种子萌发与幼苗生长的影响。研究表明,用低浓度（＜6.0mg/L)的磺胺溶液浸泡小麦种子,能显著增加幼苗的根重,根长和根冠比,提高根系活力和叶片叶绿素的含量,降低幼苗的苗高,苗重,但对发芽率影响不大。高浓度（＞10．0mg/L)和安则强烈抑制小麦幼苗根,芽的生长,并导致幼苗形态的不良变化。     

低温胁迫对番茄种子萌发的影响

在人工气候箱中模拟3个低温处理(24h最低/最高温度分别设定为7℃/12℃、5℃/10℃和3℃/8℃),分析了播种后不同天数低温胁迫对番茄种子萌发的影响。结果表明:与对照(18℃/25℃)相比,低温胁迫处理的温度越低影响越大,当日最低温度达到5.0℃、日均温低于10.0℃(相当于低温胁迫处理7℃/12℃)时,对番茄种子萌发的影响较为严重;播种后越早经受低温影响越大,播种后3d内经受低温胁迫,番茄种子发芽势、发芽指数和萌发率均有较大的下降,播种6d后低温胁迫对其萌发指标的影响较小;低温胁迫影响种子萌发的原因主要是低温导致了α-淀粉酶活性下降,相对离子渗漏率增加,从而减缓了番茄种子贮藏物质的降解,影响了番茄种子萌发初期的物质与能量代谢,并增强了细胞膜的透性,导致外渗物增多。     

外源一氧化氮对铅胁迫下小麦种子萌发及幼苗生理特性的影响

利用室内水培实验,研究了外源一氧化氮（NO）供体硝普钠（SNP）对Pb²⁺处理下小麦（Triticum aestivum L.）种子萌发、幼苗生长及相关生理指标变化的影响。结果表明,Pb²⁺处理使小麦种子发芽势、发芽率、幼苗根长和茎长均显著降低,诱导叶绿素a、叶绿素b含量减少及叶绿素荧光参数F_v/F_m和F_v/F_o的比值减小,25 μmol·L^-1 SNP明显缓解Pb²⁺胁迫对种子萌发及幼苗生长的抑制作用,提高Pb²⁺胁迫下叶绿素a、叶绿素b含量及F_v/F_m和F_v/F_o的比值,而100 μmol·L^-1SNP无明显缓解作用。此外,25和100 μmol·L^-1SNP诱导Pb²⁺胁迫下小麦幼苗叶片过氧化氢酶（CAT）活性增强和可溶性蛋白含量增多,但100 μmol·L^-1SNP处理降低了过氧化物酶（POD）活性。结果说明,外源NO促进Pb²⁺胁迫下小麦种子萌发及幼苗生长,提高叶绿素和可溶性蛋白含量,诱导CAT活性升高,从而增强小麦对Pb²⁺胁迫的适应性。     

磁化水对小麦种子萌发、幼苗生长和生理特性的生物学效应

为研究磁化水对作物的生物学效应,本文详细分析了磁化水处理对小麦种子萌发、幼苗生长和生理特性的影响。研究结果显示：磁化水处理小麦的种子发芽参数与对照相比无显著差异;磁化水处理对小麦的株高、根长、地上部和根部鲜重等生长参数也无显著影响;同样,磁化水处理在叶片色素含量、可溶性糖、可溶性蛋白质含量、含水量、细胞汁液渗透势等重要生理特征参数方面也未显示出显著差异。此外,磁化水并未显著影响小麦叶片的光合作用。综上所述,磁化水处理对小麦种子萌发和幼苗生长无明显的生物学效应。     

镉胁迫对鸡冠花种子萌发及幼苗生理生化特性的影响

采用水培法和盆栽法测定分析不同浓度Cd(0、50、100、150、200 mg/L)胁迫对鸡冠花种子萌发、幼苗生物量、叶片光合色素、渗透调节物质(可溶性蛋白、可溶性糖、脯氨酸)、丙二醛(MDA)、低分子巯基化合物(GSH、GSSG、Cys、NPT)含量以及抗氧化酶 (SOD、POD、CAT、APX)活性的影响,探讨鸡冠花耐受Cd胁迫的能力及其生理机制,为植物解毒机制提供基础资料。结果显示：(1)鸡冠花种子的发芽势、发芽率和发芽指数在低浓度Cd处理下提高,而活力指数、根长及苗长在各浓度Cd胁迫下均不同程度降低,以上指标均在低浓度(50、100 mg/L)Cd胁迫下受到显著抑制,且根长受抑制程度显著高于苗长;幼苗生物量(整株鲜重、地上部分鲜重及地下部分鲜重)在200 mg/L Cd胁迫时受到显著抑制,较对照分别下降了61.9%、58.4%和72.7%;根冠比及主根长虽未受到显著影响,但总体呈现降低趋势。(2)鸡冠花幼苗叶片叶绿素和类胡萝卜素含量在100~200 mg/L Cd胁迫下均显著降低,叶片可溶性蛋白、可溶性糖和脯氨酸含量在Cd胁迫下总体呈升高趋势,并分别在50、150、200 mg/L时显著升高。(3)鸡冠花幼苗叶片各抗氧化酶活性在Cd胁迫下呈不同变化趋势,POD和APX活性在各浓度Cd胁迫分别增加23.1%~304.2%和160.0%~280.0%;SOD活性在各浓度Cd胁迫均受到抑制,但仅在150 mg/L时显著降低43.2%;CAT活性在50~150 mg/L Cd胁迫下显著增强了46.6%~66.5%,但在200 mg/L Cd胁迫却显著降低59.5%。(4)高浓度(200 mg/L)Cd胁迫下鸡冠花幼苗叶片巯基化合物GSH、GSSG、Cys、NPT含量分别比对照上升了53.2%、164.2%、53.9%和0.79%,而GSH/GSSG比值显著降低。研究发现,鸡冠花种子萌发期和幼苗期对Cd胁迫均具有一定的耐受力,但高浓度Cd胁迫仍致使幼苗部分抗氧化酶活性降低,ROS过量积累,引起膜脂过氧化程度加深,其产物MDA含量逐渐升高;Cd胁迫促进低分子巯基化合物含量呈不同幅度的增加,但GSH/GSSG比值下降,细胞内氧化还原反应(Redox)受到抑制,导致幼苗正常生长代谢受阻,生物量持续降低。     

壳聚糖对苦瓜种子萌发过程中几个生理指标的影响

探讨壳聚糖（chitosan，CS）对苦瓜（Momordica charantiaL．）种子（广西新改良‘长丰3号’）萌发有关的几个生理指标的影响。     

Effects of phenanthrene on seed germination and some physiological activities of wheat seedling

Polycyclic aromatic hydrocarbons (PAHs) are one of the highly persistent organic pollutants, and they are toxic to plants and other living organisms, including human beings. To analyze the response of higher plant to PAHs, we investigated the effects of phenanthrene (PHE) on seed germination and various physiological changes of wheat seedlings. Specifically, we investigated growth, chlorophyll content, lipid peroxidation (LPO), activities of antioxidant enzymes and H₂O₂ accumulation. The results showed that PHE inhibited seed germination, affected the growth and chlorophyll level of wheat seedlings. Furthermore, PHE elevated the levels of LPO and induced H₂O₂ accumulation in leaf tissues in a dose-dependent manner, accompanied by the changes in the antioxidant status. The activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), displayed a decreasing trend with the increasing of PHE concentration. The results indicated that PHE could exert oxidative damages in the early development stage of wheat and the harmfulness occurred mainly in samples with higher concentrations of PHE.     

汞对萝卜种子发芽及幼苗某些生理特性的影响

研究了重金属汞离子(Hg^2 )对萝卜种子发芽及幼苗某些生理特性的影响。结果表明,随着汞离子浓度的增加和处理时间的延长,萝卜种子的发芽率和发芽指数以及幼苗的生长势和生长量均明显下降。幼苗子叶叶绿素a、b的含量下降。幼苗根系、茎叶过氧化物酶的活性则明显升高。     

Effect of aflatoxin B1 on germination index and seedling growth in wheat varieties

The effect of different concentrations of aflatoxin B₁ (100, 250, 500, 1000, 2000 µg/l) was studied on germination index and seedling growth in three varieties of wheat seeds. Inhibition in the above process was directly influenced by the concentration of toxin. Concentration of toxin had highly significant effect (p<0.001) for seed germination rate and radicle and plumule development. Inhibition dose for 50% reduction in germination rate (ID₅₀) determined by probit analysis was maximum for the variety HP-129 (895 µg/l).     

Isoenzyme changes accompanying germination of wheat seeds

Electrophoretic patterns of soluble proteins and enzymes during development from dry seed to first leaf were studied in wheat by means of disc electrophoresis. The patterns considered were those of alcohol dehydrogenase (ADH), peroxidase, and nonspecific esterases. Multiple forms (isoenzymes) were found for all these enzymes in dry seeds. The ADH pattern did not change during development. Esterases and peroxidase patterns changed both qualitatively and quantitatively. Increase in the number of peroxidase bands was marked.Research carried out at Brookhaven National Laboratory under the auspices of the U.S. Atomic Energy Commission.     

Effect of salinity on seed germination,seedling growth,and physiological characteristics of Perilla frutescens

Abstract

Salt stress is one of the major environmental factors limiting crop growth and yield. To understand the effect of salt stress on plant growth, we investigated the response of three perilla varieties (Suyin 1, Ziye 7, and Ziye 10) to NaC1 exposure at concentrations of 0, 50, 100, 150, 200, and 250 mM in terms of seed germination, seedling growth, root activity, contents of soluble sugar, proline, and malondialdehyde (MDA), and peroxidase (POD) enzyme activity. Germination characteristics, such as the percentage of seed germination, tended to decrease with increasing NaC1 concentrations. After three weeks of salt stress, the three varieties exhibited different salt tolerance in terms of seed germination, seedling growth, and physiological changes: seedling growth was inhibited to various degrees, seedling vigor and root activities decreased, and MDA, proline, and soluble sugar contents increased with increasing NaCl concentrations. POD enzyme activity, a protective mechanism against salt stress, increased at low NaC1 concentrations in Suyin1 (0–150 mM) and Ziye 7 (0–100 mM), and then decreased at higher NaCl concentrations. In Ziye 10, on the other hand, POD activity dropped significantly with increasing NaCl concentrations. These results suggest that among the three varieties Suyin 1 is more salt tolerant than Ziye 7 and Ziye 10, and that Ziye 10 is the most sensitive to salt stress.     

Se和环境中富里酸对小麦种子发芽的影响及其生理特性

利用种子发芽实验研究了亚硒酸钠（ＮＶ２ＳｅＯ３）和从土壤中提取的富里酸（Ｆｕｌｖｉｃ ａｃｉｄ, ＦＡ）对小麦种子发芽和生长的影响,以及 ＦＡ对亚硒酸钠毒性的抑制作用．结果表 明．ＦＡ和低浓度Ｎａ２ＳｅＯ３对种子发芽及发芽后的生长有促进作用,高浓度 Ｎａ２ＳｅＯ３明显 降低种子发芽率、种子活力、α－淀粉酶活性及幼苗的生长,ＦＡ对亚硒酸钠的毒性有一定的 抑制作用．     

Pyrimidine degradation influences germination seedling growth and production of Arabidopsis seeds

PYD1 (dihydropyrimidine dehydogenase) initiates the degradation of pyrimidine nucleobases and is located in plastids. In this study, a physiological analysis of PYD1 employing T-DNA knockout mutants and overexpressors was carried out. PYD1 knockout mutants were restricted in degradation of exogenously provided uracil and accumulated high uracil levels in plant organs throughout development, especially in dry seeds. Moreover, PYD1 knockout mutants showed delayed germination which was accompanied by low invertase activity and decreased monosaccharide levels. Abscisic acid (ABA) is an important regulator of seed germination, and ABA-responsive genes were deregulated in PYD1 knockout mutants. Together with an observed increased PYD1 expression in wild-type seedlings upon ABA treatment, an interference of PYD1 with ABA signalling can be assumed. Constitutive PYD1 overexpression mutants showed increased growth and higher seed number compared with wild-type and knockout mutant plants. During senescence PYD1 expression increased to allow uracil catabolism. From this it is concluded that early in development and during seed production PYD1 is needed to balance pyrimidine catabolism versus salvage.     

枯草芽胞杆菌QM3浸种后对小麦种子萌发过程中形态指标的影响

目的研究枯草芽胞杆菌QM3对小麦种子萌发过程的影响。方法用不同稀释度的QM3菌液浸种小麦种子不同时间,在培养皿中培养7 d,用计数和根系分析系统-根系图像扫描仪分别描述小麦种子的出芽指标和根部指标。结果一定浓度的枯草芽胞杆菌QM3浸种对小麦种子的萌发过程有促进作用,尤其是枯草芽胞杆菌QM3的10倍稀释液浸种12 h时对小麦萌发有利,即此处理的各项指标均高于其他的处理和对照组（P〈0.05）。结论枯草芽胞杆菌QM3对小麦种子的萌发过程中有一定的促进作用,是具有开发潜力的生防菌株。     

旋转磁场对小麦种子萌发及幼苗生长的影响

以“淮麦19”小麦种子为研究对象,采用磁场强度为11 mT的旋转磁场进行处理,设定不同的时间梯度(10、20、30、60 min),以未经磁场处理的为对照,研究了不同处理时间下旋转磁场对小麦种子发芽指标及幼苗生理特性的影响。结果表明：旋转磁场处理对小麦种子萌发具有促进作用,不同处理时间下,种子的发芽势、发芽率、发芽指数均有显著提高,随着时间的增加呈现先上升后下降的趋势,以处理30 min为最高,分别比对照提高了8.24％、7.37％、11.24％。经旋转磁场处理后,小麦根系发达,根长、根数均显著高于对照;幼苗生长加快,株高除处理60 min外,其他处理均显著高于对照,以处理30 min为最大,高出对照11.13％;叶片数除处理10 min外,其他处理均高于对照,以处理30 min为最大,比对照高出38.89％,且差异显著。旋转磁场处理显著增加了小麦幼苗的物质积累,不同处理时间表现出不同的效果,对幼苗生物积累量影响最佳的是处理20 min。这说明旋转磁场处理提高了小麦种子的萌发能力,加快了小麦幼苗的生长速度。     

Effect of age on germination of dormant seeds

Dormant seeds in permanent soil seed banks change their germination probability with age, but little is known about the causes of this behavior. Since current adaptive models do not consider the age structure of the seed bank, the sole explanation is that changes in germination probability with age are due to passive accidental factors or to decay of seeds. Here we present a theory, which shows that such changes might be adaptive. In particular, in density-regulated populations, the evolutionarily stable fraction of germinating seeds in each age class increases with age whenever age-dependent mortality of dormant seeds remains constant or increases with age.