外源激素对尖果沙枣种子萌发及幼苗生长的影响

为解决沙枣种子发芽率极低、播种出苗率低等问题,以尖果沙枣种子为试验材料,比较不同浓度的外源激素对尖果沙枣种子萌发及幼苗生长的影响。结果表明,随着GA₃和NAA浓度的增加,尖果沙枣种子萌发指标和幼苗生长指标均呈先升后降的趋势;当GA₃浓度为100 mg/L和NAA浓度为200 mg/L时,各项指标均达最大值,400 mg/L的GA₃和NAA处理对幼苗地下部鲜重有显著抑制作用,分别比对照降低了11.1%和14.8%。不同浓度的外源激素处理对尖果沙枣种子的萌发和幼苗生长有显著差异,GA₃浓度100 mg/L、NAA浓度200 mg/L是尖果沙枣种子萌发及幼苗生长的最适浓度,外源激素浓度过高会抑制尖果沙枣种子萌发及幼苗生长。     

外源生长调节物质对甜高粱种子萌发过程中盐分胁迫的缓解效应及其生理机制

盐渍化土壤中盐胁迫是作物种子萌发和生长发育的主要限制因子, 探究盐分胁迫下提高种子萌发率的技术及机制对开发利用盐碱地有重要意义。本文以不同耐盐能力的高粱品种国甜2011和国甜106为材料, 研究了盐分对甜高粱种子萌发期生长过程的影响, 并比较了耐盐性差异。以耐盐性弱的国甜106为试材, 探究盐分胁迫下不同生长调节物质[γ-氨基丁酸(GABA)、赤霉素(GA₃)、激动素(KT)和水杨酸(SA)]对甜高粱种子吸水萌发过程中生长特性的调节效应。表明, 盐分胁迫显著抑制种子的吸水萌发, 降低种子的吸水速率、发芽势、发芽率、发芽指数, 增加种子的相对盐害率和丙二醛(MDA)含量。外源生长调节物质可有效缓解盐害, 显著增加种子的吸水率、发芽率、可溶性糖含量、可溶性蛋白含量, 提高SOD (超氧化物岐化酶)、POD (过氧化物酶)、CAT (过氧化氢酶)的活性, 促进K ⁺、Ca ²⁺、Mg ²⁺离子的吸收, 降低Na ⁺和MDA含量。外源生长调节物质主要是通过提高保护酶活性、渗透调剂物质含量和维持体内离子平衡来提高耐盐性。GA₃和GABA对盐害的缓解效应较好, 而KT促进种子对Mg ²⁺的吸收效果较好。本研究表明外源生长调节物质(尤其是 GA₃和 GABA)可用于盐碱地高粱生产, 为减轻盐碱地对高粱的盐碱胁迫提供了理论依据。     

Na2CO3对黄秋葵种子萌发及生理特性的影响

为研究碱环境下黄秋葵种子萌发及生理特性,采用不同浓度(0、10、20、30、40 mmol·L^-1)Na2CO3溶液处理黄秋葵种子,测定其种子的萌发特性、胚根生长速度及第3天时胚根的生理特性。结果表明,随着碱浓度的增加,种子的发芽率、发芽势、发芽指数呈下降趋势,相对碱害率升高;发芽期间胚根长度与碱浓度呈负相关关系,且生长速度降低;碱胁迫下种子的抗氧化物酶(POD、CAT、SOD)活性较对照组无显著变化,MDA随碱浓度增加呈升高趋势,脯氨酸积累量变化不明显。发芽7 d后对照和10 mmol·L^-1碱液处理可萌发为幼苗,对其复水5 d后,发现10 mmol·L^-1处理侧根生长量远少于对照组。说明碱胁迫能抑制黄秋葵种子萌发及其幼苗生长,但黄秋葵种子对10 mmol·L^-1碱胁迫具有耐受性。     

NaCl胁迫下西瓜种子对蛭石引发的响应

以西瓜品种“小皇冠”和“早佳8424”种子为试验材料，采用种子萌发袋发芽的方法，研究在不同浓度(0,50,75,100,125 mmol/L) NaCl溶液胁迫下，蛭石引发处理对西瓜种子发芽指标及幼苗生理特性的影响，探讨引发处理对缓解西瓜盐胁迫伤害的可行性。结果表明，随着NaCl浓度增加对西瓜种子萌发的抑制作用逐渐加剧，引发处理提高了NaCl胁迫下西瓜种子发芽势和发芽率；NaCl胁迫下，西瓜胚根超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性升高，过氧化氢(H₂O₂)、丙二醛(MDA)和可溶性糖含量增加；引发处理下胚根的SOD、POD、CAT活性增强，MDA和H₂O₂含量减少，可溶性糖含量增加。研究表明，引发处理能促进NaCl胁迫下西瓜种子萌发，促进可溶性糖的积累，诱导抗氧化酶活性，降低MDA和H₂O₂的积累，增强西瓜幼苗的耐盐性。     

盐碱胁迫对白榆种子萌发和幼苗生长的影响

以常见的园林绿化树种白榆(Ulmus pumila L.)种子为材料,利用浓度分别为0,100,200mmol/L的中性盐NaCl和浓度分别为0,25,50mmol/L的碱性盐Na_2CO_3混合模拟出9种不同的盐碱胁迫处理,研究不同处理对白榆种子萌发率及幼苗生长的影响效应。结果表明:低盐(100mmol/L NaCl)处理对白榆种子萌发没有抑制效应,但高盐(200mmol/L NaCl)处理对白榆种子萌发有显著的抑制作用,表现为发芽率、发芽势、发芽指数、活力指数均显著降低;低碱(25mmol/L Na_2CO_3)处理对白榆种子萌发抑制作用不显著,但高碱(50mmol/L Na_2CO_3)处理抑制效果显著,且抑制效果显著强于高盐处理,白榆种子几乎不发芽。复合盐碱胁迫处理下,低盐低碱和高盐低碱复合胁迫对种子萌发率抑制效果不显著,但对幼苗生长抑制效果显著,表现为胚芽、胚根数量和长度减少;低盐高碱和高盐高碱混合胁迫对种子萌发率抑制效果显著,特别是高盐高碱混合胁迫下,种子几乎不发芽,发芽后的胚芽和胚根几乎不生长。     

人工模拟盐、碱环境对向日葵种子萌发及幼苗生长的影响

以向日葵品种白葵杂6号为试验材料, 中性盐NaCl和Na₂SO₄混合模拟盐胁迫、碱性盐NaHCO₃和Na₂CO₃混合模拟碱胁迫(两者摩尔比均为9∶1), 设计各6种处理。研究盐、碱胁迫下种子萌发及幼苗形成的相关生理表现。结果表明, 种子能够萌发并成苗的最高盐胁迫强度是pH 6.98, 电导率为1.311 dS m^-1(培养介质的pH和电导率); 碱胁迫强度是pH 9.71, 电导率为0.360 dS m^-1。在能够成苗的盐碱条件下, 随着盐胁迫强度的增强出苗率、成苗率下降, 出苗时间明显延迟; 而随着碱胁迫强度的增加, 成苗率下降, 出苗时间并不延迟。同时随着盐碱胁迫强度的增强, 幼苗的各项生理指标均下降, 下降幅度以碱胁迫明显大于盐胁迫。试验结果证明, 盐胁迫和碱胁迫对白葵杂6号种子萌发及幼苗形成的影响机制不同, 向日葵在这两个阶段对盐碱两种胁迫的耐受能力及响应特点也不同。这一结论进一步证实了盐、碱胁迫是两种性质不同的胁迫。     

引发对干旱胁迫下菠菜种子萌发的影响

以"宏福"菠菜种子为材料,采用种子活力试验及种子激素测定法研究引发处理对干旱胁迫下菠菜种子萌发的影响。结果表明,干旱胁迫可抑制菠菜种子萌发,且随着干旱胁迫的增强菠菜种子的发芽势、发芽率、发芽指数急剧下降,而引发处理可有效缓解干旱胁迫对菠菜种子萌发的抑制作用,同未引发处理相比,PEG和谷氨酸钠引发处理缓解干旱胁迫的作用显著。此外,赤霉素处理能显著提高GA3/ABA比值,高GA3/ABA可使种子休眠解除。     

种子引发对干旱胁迫下高粱种子发芽及生理特性的影响

萌发期的干旱胁迫是限制高粱生产的主要障碍因子，种子引发是提高作物抗逆性的一个重要技术。为了明确不同引发处理对干旱胁迫下高粱萌发及生理特性的影响，以晋杂22和晋早5564为研究材料，分别进行聚乙二醇（PEG）、KCl、CaCl₂、水杨酸（SA）引发和未引发（NP）5个处理，研究在正常情况和干旱胁迫下种子发芽情况及生理特性变化。结果表明，干旱胁迫显著降低高粱种子发芽率，抑制胚芽和胚根伸长。干旱胁迫下PEG、KCl、CaCl₂和SA引发后，晋杂22的萌发率比NP处理分别提高了18.18%、12.72%、35.45%和31.82%，晋早5564的萌发率比NP处理分别提高了20.18%、10.76%、26.91%和30.04%。干旱胁迫下，引发处理促进了胚根和胚芽的伸长，CaCl₂和SA处理在晋杂22抗旱效果最佳，芽长分别比NP处理增加了267.07%和271.95%，根长分别比NP处理增加了231.94%和355.56%。CaCl₂处理在晋早5564效果最好，芽长和根长分别比NP处理增加了195.96%和206.60%。种子引发提高了胚芽内抗氧化酶活性，减轻了膜脂过氧化对胚芽的损伤；同时种子引发促进了糖代谢，提高了脯氨酸含量，缓解了干旱胁迫对种子萌发的抑制效应。     

PEG-6000和盐碱胁迫对甜高粱种子萌发影响研究

甜高粱种子萌发阶段对逆境胁迫比较敏感,为探讨干旱胁迫与盐碱胁迫对甜高粱种子萌发影响的不同机制,以辽甜1号甜高粱种子为材料,采用不同浓度PEG-6000模拟干旱胁迫,不同浓度NaCl和NaHCO_3溶液模拟盐碱胁迫,分析比较甜高粱种子萌发阶段对干旱、盐碱胁迫的响应特性。结果表明:低浓度的NaCl(50 mmol·L~(-1))处理,种子的发芽率和发芽势升高,表现出促进种子萌发的作用,低浓度的PEG-6000和NaHCO_3处理抑制种子的发芽率和发芽势等萌发指标,中高浓度的PEG-6000、NaCl和NaHCO_3处理均显著抑制种子的各类萌发指标,不同浓度的PEG-6000、NaCl和NaHCO_3处理均显著影响种子的干物质转移和早期幼苗生长,其中NaHCO_3胁迫影响最大,PEG-6000胁迫影响次之,NaCl胁迫影响最小。本研究结论可为干旱和盐碱地区提高甜高粱种子萌发和幼苗生长提供理论依据和技术指导。     

不同细胞活性物质对低温下通草种子及幼苗的影响

通草是贵州一种道地中药材，播种育苗时常会遇到春季低温的影响，导致其发芽率较低。本研究采用不同浓度的不同细胞活性物质硝普钠(SNP)、海藻糖(TH)和赤霉素(GA₃)进行种子引发，研究在常温和低温胁迫下不同细胞活性物质不同浓度处理对通草种子萌发及幼苗生长的影响。结果表明，适合浓度的SNP引发可显著改善通草种子在低温胁迫下的发芽势、发芽率、发芽指数，缩短发芽时间，增加幼苗的根长、苗高和干鲜重，其中以200μmol/L SNP引发的效果最好，而其他处理的效果不佳，表明适合浓度的SNP引发可提高通草种子及幼苗对低温的耐受性。     

The Influence of Fertilizer-based Seed Priming Treatments on Emergence and Seedling Growth of Sorghum bicolor and Pennisetum glaucum in Pot Trials under Greenhouse Conditions

The effect of priming sorghum and pearl millet seeds with fertilizers was investigated. Two experiments were conducted on M35–1 (sorghum) and ICMH 356 (pearl millet), and ICSV 745 (sorghum) and Barmer (pearl millet) seeds, respectively. Treatments included nitrogen, phosphorous and potassium-based treatments which showed that 7.5 g l⁻¹ of urea substantially enhanced the final germination percentage of seeds. The second experiment included 10 priming treatments with 7.5 g l⁻¹ urea mixed with other fertilizers. Results indicated that soaking seeds for 3 days in urea + one of several fertilizers including N, P or K-based nutrient compositions or micro elements significantly increased germination percentage and speed but did not affect seedling growth at 15 or 60 days after sowing. It is concluded that seed priming treatments with fertilizers may serve as an appropriate treatment for advancing germination of the species studied.     

Seed Composition, Seedling Emergence and Early Seedling Vigour of Red Kidney Bean Seed Produced at Elevated Temperature and Carbon Dioxide

Understanding the influence of growth temperature and carbon dioxide (CO₂) on seed quality in terms of seed composition, subsequent seedling emergence and early seedling vigour is important under present and future climates. The objective of this study was to determine the combined effects of elevated temperature and CO₂ during seed-filling of parent plants on seed composition, subsequent seedling emergence and seedling vigour of red kidney bean ( Phaseolus vulgaris ). Plants of cultivar 'Montcalm', were grown at daytime maximum/nighttime minimum sinusoidal temperature regimes of 28/18 and 34/24 °C at ambient CO₂ (350 μmol mol⁻¹) and at elevated CO₂ (700 μmol mol⁻¹) from emergence to maturity. Seed size and seed composition at maturity and subsequent per cent emergence, early seedling vigour (rate of development) and seedling dry matter production were measured. Elevated CO₂ did not influence seed composition, emergence, or seedling vigour of seeds produced either at 28/18 or 34/24 °C. Seed produced at 34/24 °C had smaller seed size, decreased glucose concentration, but significantly increased concentrations of sucrose and raffinose compared to 28/18 °C. Elevated growth temperatures during seed production decreased the subsequent per cent emergence and seedling vigour of the seeds and seedling dry matter production of seed produced either at ambient or elevated CO₂.     

Temperature, Osmotic Pressure and Seed Treatments Influence Imbibition Rates in Sorghum Seeds

Imbibition is an essential part of the germination process and is affected by various environmental factors. The effects of temperature, seed treatment, storage and osmotic pressure on primed and untreated sorghum seed were examined. The potential influence of NaCl‐based seed‐soaking treatments was also investigated. Experiments on sorghum seeds showed that imbibition rates were higher in untreated than in primed seeds after more than 24 h of soaking and that a rise in priming temperature increased imbibition to a greater extent in the former. The influence of imbibition in regulating the seed response to priming, heat and osmotic stress is discussed.     

盐引发对不同水分条件下油菜种子发芽成苗的影响

试验用两个油菜(Brassica napus L.)品种"双72"和"浙油758"研究了Ca(NO3)2溶液引发对油菜种子在不同水分条件下发芽和幼苗生长的影响,探讨通过引发来提高大田直播油菜的活力.结果表明,经过引发处理后,两个油菜品种在30%的水分条件下无法发芽;在20%和25%的水分条件下种子的发芽指数显著提高,平均发芽天数显著缩短,幼苗POD活性显著提高,而幼苗的根长、苗高、苗干重、叶绿素含量和CAT活性与对照相比没有显著差异.引发后的"浙油758"种子在20%和25%水分条件下,发芽势和发芽率显著提高,而"双72"种子的发芽势在20%水分时显著高于对照.试验表明盐引发提高了油菜种子在水分逆境下的活力,提高了幼苗的抗逆性.     

Hydro-Priming Methods for Initiation of Metabolic Process and Synchronization of Germination in Mung Bean (<Emphasis Type="Italic">Vigna Radiata</Emphasis> L.) Seeds

Seed priming is a commercially applied technique for improving seed vigor under variable field conditions. The present study was carried out to optimize the methods (direct: soaking in water 1:1 W/V and indirect: preconditioning under high RH ≥ 85%) and duration (hours)of hydro-priming, attempting to correlate the critical seed water content with priming-induced metabolic-restart in dry mungbean (Vigna radiata L.)seeds. Although the rate of water absorption and the amount of water absorbed was more by direct compared to the indirect imbibition method, the priming-induced germination responses were identical after 6hof priming treatment. The seed water content absorbed during this period was crucial for initiating the chain of biochemical events, required for early synchronized germination in primed seeds which was evident by improved membrane permeability, high activity of catalase and superoxide dismutase, and more integrated chloroplast and mitochondria in primed seeds. We demonstrate that the critical water content, required for priming-induced benefits for germination vigor, is a relative unit with respect to the duration of priming and the rate of water absorption. Seed priming is a co-ordinately regulated mechanism for controlling germination capacity of seeds by modifying the permeability characteristics of biological membranes and enzyme activity. This study helps to enhance our understanding on the potential of seed priming for synchronized germination and early seedling establishment in the field and beneficial for the resource poor farming community for better return of their limited financial/farm resources under variable environmental/field conditions.     

种子引发对水分胁迫下水稻发芽及幼苗生理性状的影响

不同基因型稻种经水引发及聚乙二醇(PEG)渗透胁迫引发处理均能降低稻种丙二醛(MDA)含量,促进可溶性总糖(SS)降解,加快稻种内部糖代谢进程,提高相溶性溶质脯氨酸(Pro)及可溶性蛋白质(SP)含量,也有利于提高苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,引发效果较明显。且适度PEG引发稻种的效果明显好于水引发,杂交籼稻在PEG浓度为20%的条件下引发效果最优,而常规粳型水稻在PEG浓度为10%~15%的引发条件下效果较好,但超出最高PEG引发浓度的阈值,会对稻种产生危害,影响其正常萌发。引发处理后的稻种对不同程度水分胁迫程度的响应表明,适当强度的引发处理利于激发稻种物质代谢、利于各水稻品种的萌发、幼苗形态指标及保护性酶等生理指标的显著提高,而严重的水分胁迫均不利于稻种萌发;表明引发处理虽能提高水分胁迫条件下种子活力,但稻种激发自身对外界萌发环境的协调能力有限,且不同品种间存在明显差异,籼稻优于粳稻。     

Plant Emergence of PEG-osmoprimed Seeds under Suboptimal Temperatures in Two Cultivars of Sweet Sorghum Differing in Seed Tannin Content

The effect of polyethylene glycol (PEG) osmopriming on plant emergence in laboratory at optimal (25 °C) and suboptimal (18 and 14 °C) temperatures was assessed in two cultivars of sweet sorghum differing in kernel colour: Brandes, light-coloured, and Roce, dark-coloured. Sterilized sand or non-sterilized soil were used as substrates. PEG osmopriming enhanced seedling emergence in sand. In soil, the light-seeded cultivar produced seedlings only at optimum temperature, whereas the unprimed dark-seeded cultivar performed well as in sand at all temperatures and reduced dramatically its germination capacity at suboptimal temperatures following priming treatment. These results might be related to the presence of tannins in the seed coat. Seed tannin contents of 80 and 590 mg 100 g⁻¹ seed fresh weight (FW) were determined in Brandes and Roce respectively. These amounts consistently reduced after PEG osmopriming, especially in Roce (217.5 mg 100 g⁻¹ seed FW). The decline in tannin content in Roce, because of osmopriming, might explain the poor emergence of this cultivar in soil. These results suggest the opportunity of using high-tannin cultivars of sweet sorghum in the field, which may better growth in this environment when early sowings are required.     

Seed treatments to overcome salt and drought stress during germination in sunflower (Helianthus annuus L.)

The treated seeds (control, KNO₃ and hydropriming) of sunflower (Helianthus annuus L.) cultivar Sanbro were evaluated at germination and seedling growth for tolerance to salt (NaCl) and drought conditions induced by PEG-6000 at the same water potentials of 0.0, −0.3, −0.6, −0.9 and −1.2 MPa. Electrical conductivity (EC) values of the NaCl solutions were 0.0, 6.5, 12.7, 18.4 and 23.5 dS m⁻¹, respectively. The objective of the study was to determine factors responsible for germination and early seedling growth due to salt toxicity or osmotic effect and to optimize the best priming treatment for these stress conditions.

Results revealed that germination delayed in both solutions, having variable germination with different priming treatments. Germination, root and shoot length were higher but mean germination time and abnormal germination percentage were lower in NaCl than PEG at the same water potential. Seeds were able to germinate at all concentrations of NaCl but no seed germination was observed at −1.2 MPa of PEG treatments. NaCl had less inhibitor effect on seedling growth than the germination. It was concluded that inhibition of germination at the same water potential of NaCl and PEG resulted from osmotic effect rather than salt toxicity. Hydropriming increased germination and seedling growth under salt and drought stresses.