四种常见针叶树种种子发芽对水分胁迫的响应

本文通过用PEG(聚乙二醇)配制不同浓度溶液,模拟不同土壤水势梯度,达到不同水分胁迫水平,进行柳杉、杉木、马尾松、侧柏等树种种子发芽水分胁迫实验。研究结果表明;水势在0～-0.6Mpa,除马尾松外,其余三种树种随水势下降,种子发芽率、发芽指数、苗长、活力指数均呈下降趋势。水势降至-0.86 Mpa时,各树种种子发芽均受完全抑制。其中侧柏在水势降至-0.6Mpa时,种子发芽已受完全抑制。综合比较,各树种种子的耐旱能力大小依次为:马尾松>杉木>柳杉>侧柏。     

水分胁迫对日本柳杉种子萌芽的影响

本文采用配置不同浓度的PEG(聚乙二醇)溶液来模拟土壤自然水势，对日本柳杉种子萌芽实验进行人工水分胁迫处理。结果表明：随着水势的下降，其发芽率在轻度水分胁迫下有所上升，然后降低，随PEG浓度上升到15％时，发芽率、发芽速度、发芽指数、活力指数、芽长等都出现不同程度的降低。而当PEG浓度上升到25％时，则上述指标均受到强烈抑制。结果表明，日本柳杉在轻度干旱胁迫时，具有一定的耐旱性。     

水分胁迫对不同产地金银花种子发芽的影响

采用不同浓度的PEG对不同地区金银花其他种子萌发进行人工水分胁迫处理,结果表明,随着水势的下降,除少数地区金银花种子发芽指数在轻度胁迫下略有上升外,其他各种金银花种子发芽率、发芽指数、活力指数、芽长总体呈下降趋势,不同金银花变化趋势相似,但变化幅度有明显差异。综合评价初步认为,贵州遵义和贵州花溪2金银花耐旱性相对较强;山东金银花耐旱性最弱;贵州麻江、河南封丘、贵州花溪1和内蒙古金银花耐旱性居中。     

聚乙二醇模拟干旱对三种木麻黄种子萌发的影响

为研究木麻黄Casuarinaceae.种子苗困难地造林,以木麻黄为试验材料,用不同渗透势浓度的聚乙二醇(PEG-6000)模拟干旱胁迫,探讨干旱胁迫对木麻黄种子发芽率、发芽势、胚轴和胚根长度及发芽指数、活力指数的影响。结果表明,不同浓度PEG胁迫处理均降低了种子的发芽率,延缓了木麻黄种子萌发进程;种子的发芽率、发芽指数和活力指数均随胁迫强度的增加呈明显下降趋势。当-1.20 MPa的PEG胁迫处理的种子在试验结束时仍未能萌发,表明-1.20 MPa是木麻黄种子萌发的临界水势。当PEG浓度为150 g/L时,三种木麻黄幼苗的胚根最长,且当PEG浓度为100 g/L时,三种木麻黄胚根长度长于对照组,但差异不显著,说明高于-0.40 MPa的水势有利于木麻黄种子胚根的生长。木麻黄幼苗苗高生长则是随着PEG浓度的升高而逐渐减缓。通过比较得知木麻黄种子抗旱性较强。     

任豆种子发芽对干旱胁迫的响应

为研究任豆种子的耐旱特性,配置不同浓度的聚乙二醇模拟干旱亏缺环境,对任豆种子萌芽进行干旱胁迫。结果表明,任豆种子萌发的水势范围是0~(-0.60)MPa,随着干旱胁迫加剧,种子发芽率、发芽势、发芽指数、芽长和活力指数呈明显下降的趋势;当水势为-0.86 MPa时,种子便不能发芽。干旱胁迫对任豆种子发芽的影响较大。     

PEG模拟干旱对毛竹种子萌发及生长生理特性的影响

[目的]通过比较不同程度干旱胁迫对毛竹种子萌发及生长生理的影响,探究毛竹种子萌发期对水分胁迫的耐受机理,为毛竹的水分管理提供科学依据。[方法]以毛竹种子为试验材料,采用培养皿滤纸萌发的方法研究不同浓度(0%、5%、10%、15%、20%、25%) PEG-6000溶液对其种子萌发、生长、渗透调节物质、抗氧化酶活性的影响。并对种子萌发率、胚根和胚芽的生长量与PEG胁迫浓度间进行回归分析。[结果](1)对照组(CK)和5%处理组在第4天开始发芽,其余各处理组的发芽起始时间随处理浓度的升高逐渐延迟,25%处理组不发芽。(2)最终发芽率、发芽势、发芽指数、活力指数、胚根长度、胚芽长度随PEG浓度的升高呈现先增大后减小的趋势,且均在5%浓度达到最大值。干旱胁迫下毛竹种子发芽率日变化曲线中对照组和5%处理组间存在唯一交叉点。毛竹种子在PEG胁迫下发芽率的临界值和极限值分别为14. 49%和19. 27%。(3)胚根和胚芽最终长度均在5%浓度时达到最大值,其后随着浓度的升高而减小,处理间差异显著(P 0. 05)。对照组和5%处理组的胚根平均长度日变化曲线存在交叉点。PEG胁迫下胚根生长的临界值和极限值分别为20. 43和23. 01%。(4)胚根中SOD、POD、CAT的活性均随PEG浓度的升高呈先上升后下降的趋势,且分别在5%、10%、10%浓度时达到最大值。(5) MDA和可溶性蛋白含量随PEG浓度的升高而持续升高,但低浓度(0%10%)时MDA含量差异不显著。[结论]低浓度干旱胁迫抑制发芽前期毛竹种子萌发以及胚根的形成,但显著提高毛竹种子的最终发芽率并且促进胚根后期的生长;而高浓度PEG干旱胁迫延迟毛竹发芽,抑制整个发芽时期的发芽率以及胚根、胚芽的生长; PEG浓度高于15%的干旱胁迫使毛竹的抗氧化酶系统发生紊乱,并对组织膜系统造成显著伤害。     

干旱和盐胁迫对紫叶小檗种子萌发的影响

以紫叶小檗种子为试验材料,采用聚乙二醇(PEG)和氯化钠(NaCl)模拟胁迫环境,研究不同浓度PEG、NaCl及PEG和NaCl联合处理对种子萌发各项指标的影响。结果表明,不同浓度PEG、NaCl及PEG和NaCl联合胁迫对紫叶小檗种子的萌发参数均达到了极显著水平;单纯NaCl、PEG胁迫下,随着其浓度的增加,紫叶小檗种子的发芽率、发芽势、发芽指数均呈下降趋势;当PEG浓度达到30%时,种子不发芽;二者共同影响下,种子各萌发参数下降程度增大,在25%PEG和0.15%NaCl联合胁迫下,达到完全抑制。综合考虑,紫叶小檗种子对干旱胁迫较盐胁迫更加敏感,干旱胁迫和盐胁迫同时存在对其种子萌发的影响更大。     

干旱胁迫对亚麻萌发的影响

以不同渗透势的PEG(6000)溶液模拟干旱胁迫条件,研究亚麻种子的萌发、幼苗生长和电导率对干旱胁迫的响应。结果表明,适宜浓度的PEG对亚麻种子的发芽率和发芽势并没有显著影响,但可以促进种子的萌发,加快种子的发芽速度,同时可以提高种子的发芽指数和活力指数。当PEG浓度达到30%时,仍有50%以上的种子能萌发,但随着胁迫时间的增加,亚麻种子的发芽率、发芽势、发芽指数和活力指数呈现明显下降的趋势。而不同程度的PEG胁迫,使得电解质外渗率均小于对照。从实验中可以看出,亚麻种子萌发可以忍耐的最大渗透势为-0.8MPa,说明亚麻具有一定的适应干旱能力。     

PEG-6000模拟干旱胁迫和温度对岩柿种子发芽的影响

为了解干旱胁迫和不同温度处理对岩柿种子萌发的影响，明确岩柿种子萌发适宜温度和耐旱程度，探讨岩柿种子萌发期的抗旱能力。以岩柿种子为材料，在10℃、15℃、20℃、25℃、30℃等不同温度下开展PEG-6 000溶液（0%、5%、10%、15%、20%、25%）模拟干旱胁迫试验。试验结果表明：(1)低温（0℃、10℃）种子不能萌发，重度干旱胁迫(25%PEG)种子不萌发。(2)岩柿种子能在温度为15℃、20℃、25℃、30℃和PEG轻度干旱（5%PEG）、中度干旱（10%、15%PEG)和重度干旱（20%PEG)下萌发，超过10%PEG浓度种子萌发指标受到不同程度的抑制。(3)随着PEG浓度的增加，种子受胁迫程度越高，种子各项发芽指标均呈现先增加后减少的趋势。结论：岩柿种子萌发受温度和干旱胁迫的影响较大，种子萌发适宜温度为20℃～30℃，PEG耐旱范围是0～25%PEG的干旱条件。发芽率与PEG浓度有着显著的负相关（P<0.05)，发芽指数、活力指数与PEG浓度有着极显著的负相关（P<0.01)。抗旱指数与PEG浓度呈负相关，两者相关性不显著（P>0.05)。     

聚乙二醇模拟干旱胁迫对榆树种子萌发影响

为探究干旱条件下榆树种子的发芽特性,以榆树种子为试验材料,采用滤纸发芽法,研究聚乙二醇(PEG)模拟干旱对其种子萌发的影响。结果表明:不同浓度的PEG干旱胁迫对榆树种子萌发有不同影响,5%浓度的PEG胁迫对榆树种子的萌发有明显的促进作用;榆树种子可耐5%~10%PEG浓度的干旱胁迫,而15%浓度的PEG胁迫明显抑制榆树种子萌发,20%浓度的PEG胁迫则对其种萌发有严重抑制作用。榆树的种子耐旱适宜范围、种子耐旱半致死浓度、种子耐旱极限浓度对应的PEG浓度分别为7.71%、12.33%、19.73%。     

Seed bank and regeneration dynamics of Emmenopterys henryi population on the western side of Wuyi Mountain,South China

Emmenopterys henryi Oliv.(Rubiaceae) is an endangered tree species that is native to China.The wild populations of E.henryi have declined rapidly because of its poor natural regeneration,but the actual regeneration processes are not yet understood.In field tracking surveys and experiments in the Wuyishan Nature Reserve in Southeast China to determine the most important stage that affects the regeneration process,seed bank characteristics,seed germination,and seedling growth dynamics were studied in the typical habitats of E.henryi,Phyllostachys pubescens and broad-leaved forests.Results showed that in both P.pubescens and broad-leaved forests,more than 70% of the E.henryi seeds were distributed in moss and litter layers,and few were found in the soil beneath them.However,seed germination in the soil layer was significantly higher than in the moss and litter layers.Seed density,overall seed quality,and germination rate in the broad-leaved forest were significantly higher than in P.pubescens forest.Seed germination was highest in the microsites around the edge of the crown projection area of E.henryi mother trees.The order of survival rate of the seedlings on different ground surfaces was soil mosslitter.In both habitats,the average seed density was 24.9 seeds m~(-2),and the total germination rate was less than 3.5%.However,seedlings developed from only 1% of the germinated seeds,indicating that the seed germination is the most important stage in the natural regeneration of E.henryi.     

珍稀树种香果树的利用价值及实用繁殖技术

香果树是我国特有单种属珍稀阔叶树种,属国家Ⅱ级重点保护野生植物,具有较高的推广价值。结合生产实践经验和目前有关科研进展,综合论述了香果树的开发利用价值以及关键培育技术,为开发利用香果树提供了科学理论基础。     

Effects of drought stresses induced by polyethylene glycol on germination of Pinus sylvestris var. mongolica seeds from natural and plantation forests on sandy land

Effects of drought stresses induced by polyethylene glycol (PEG) (0.0%, 10%, 15%, 20%, 25%, and 30%, with four replicates) on germination of Mongolian pine (Pinus sylvestris var. mongolica) seeds produced in plantations (southern Keerqin sandy land) and natural forests (Hulunbeier sandy plain) were observed. The results indicated that the seeds from both provenances did not germinate when PEG concentration was more than 25%. The time of initial germination and that of its completion of stressed seeds from both provenances were delayed when compared with the unstressed seeds. The germination capacity and germination rate of natural seeds were significantly higher than those of plantation seeds for all treatment levels (P < 0.05). The mean growth rates of radicle and hypocotyl from natural seeds were significantly higher than those from plantation seeds at all treatment levels below 20% PEG treatment (P < 0.05). The ratios of radicle to hypocotyl of 20% PEG treatment were significant higher than those of the corresponding controls for both provenances (P < 0.05). These results suggested that Mongolian pine seeds/seedlings had stronger resistance to PEG drought stresses; 10% PGE stress did not significantly influence germination. Natural seeds exhibited more resistance to PEG stress than plantation seeds. It was concluded that drought stress on seed germination might be one cause of obstructed natural regeneration of Mongolian pine plantations on sandy land. It is recommended that natural seeds be used for afforestation, and light drought stress (e.g., 10% PEG stress) may be useful in improving seed germination and the growth of radicles and hypocotyls.     

香果树繁殖技术研究进展

介绍了香果树的生物学特性,对香果树的有性繁殖和无性繁殖技术等方面的研究进行了概述,提出了目前在繁殖技术上存在的问题及其对策。最后对香果树今后的繁殖研究方向进行了展望。     

预处理对巴西盾柱木种子吸涨、活力测试及其加速老化的影响

对巴西盾柱木(Peltophorum dubium)种子进行了4种处理的吸胀实验,即将种子分别置于10℃和27℃下0.2% Captan溶液中和-1.0MPa的PEG6000溶液中,每个处理有四个重复,40粒种子,置于培养皿中浸满实验溶液的双层过滤纸上,覆以透气良好的薄膜.种子在实验前均用98%的浓硫酸处理15分钟以打破机械休眠.吸胀曲线显示,种子在吸胀过程中最终重量的增加值为70%-150%,以后进入一个停滞期.在5种处理下(对照组,PEG6000溶液中10℃和27℃下预处理,Captan溶液中10℃和27℃下预处理),对种子萌发所受到的影响进行了实验.每一个处理分别进行3个次级处理,即在实验前,将种子用蒸馏水分别浸泡12、24和36小时.萌发率最高的是经过蒸馏水浸泡12小时对照组种子和PEG 27℃组的种子,萌发率达到100%;萌发率最低的是蒸馏水中浸泡36小时的PEG 27℃组的种子,萌发率为52%;经过蒸馏水浸泡24小时的PEG 10℃组种子的平均萌发时间为1.08天.蒸馏水中浸泡12小时的PEG 27℃组种子平均萌发时间为2.42天,其它处理的萌发时间值介于两者之间.对预处理和未经预处理种子通过加速老化实验,对其活力和生存力进行了测试.经72小时加速老化,种子萌发率低或没有萌发力.对照组种子在培养皿(27℃)和室温条件下蛭石中的萌发率都比处理组高,表现了对老化更强的抗性.     

Germination,osmotic adjustment,and antioxidant enzyme activities of gibberellin-pretreated <Emphasis Type="Italic">Picea asperata</Emphasis> seeds under water stress

Germination of dragon spruce (Picea asperata Mast.) seeds pretreated with gibberellin (GA) in response to water stress and changes in the levels of osmotic adjustments as well as in activities of antioxidant enzymes were investigated. With decreasing water potential caused by increasing concentrations of PEG 6000, germination percentage and germination index decreased gradually; the decrease was especially prominent under the serious water stress from PEG −0.6 MPa. In contrast, osmotic regulation substances (free proline and soluble sugar contents), lipid peroxidation (MDA), and activities of antioxidant enzyme (ascorbate peroxidase, catalase, and peroxidase) increased markedly with decreased water potential. Similarly, the values in all parameters under −0.6 MPa PEG treatment were markedly higher than the control and −0.2 MPa PEG treatment. These results suggested that P. asperata seed germination was insensitive to water stress. In addition, seeds pretreated with GA had increased tolerance to water stress as measured by germination percentage and germination index, osmotic regulation substance, and antioxidant enzyme activities.     

果翅、盐分及干旱胁迫对白梭梭种子萌发的影响

从生态学角度研究了果翅、温度、盐分和干旱胁迫等因素对白梭梭种子萌发的影响,结果表明:去除种翅能显著促进种子萌发,无翅种子比有翅种子萌发速率快(P<0.05),提早1 d达最高萌发率。变温条件有利于种子萌发。白梭梭种了萌发率随着NaCl浓度增加而降低,但在0.9 mol.L-1的浓度中仍有2%的种子萌发;将未萌发的种子移至蒸馏水中后,部分种子可以萌发,在较低浓度盐溶液(0.05～0.6 mol.L-1)中培养的种子其萌发恢复率低,而高浓度(0.7～1.0 mol.L-1)中培养的种子其萌发恢复率高。在较低程度的干旱胁迫下,白梭梭种子迅速萌发,而较高程度的干旱胁迫下种子萌发受抑制,在PEG浓度50%时不萌发;同等干旱胁迫程度下,无翅种子比有翅种子萌发率高。     

油松种子“引动”处理对发芽效果的影响

试验测定了不同化学药物、浓度、浸泡时间和单纯用水浸泡渗透处理对油松种子发芽的影响。结果表明,阿司匹林、赤霉素、聚乙二醇对油松种子发芽有显著的促进作用,经过3种药物处理的种子在室温11~14℃的情况下,第6天或第7天开始发芽,对照第9天发芽;发芽势（第10天的发芽率）经过处理的在22%以上,高者可达31%,而对照仅为8.3%。单用自来水做渗透引动处理也能提高油松种子的发芽势和发芽率。