薄壳山核桃根系水浸提液对2种作物种子萌发及幼苗生长的影响

为探讨薄壳山核桃根系水浸提液对小麦、大豆的影响,采用蒸馏水浸提法收集薄壳山核桃根系化感物质,并运用室内生物测定法检测不同浓度(0.025、0.05和0.1 g·mL~(-1))根系水浸提液对小麦、大豆种子萌发和幼苗生长的影响。结果表明:各浓度处理的根系水浸提液对小麦、大豆萌发及幼苗生长的化感抑制作用较为显著,且具有显著的浓度效应(浓度低抑制作用弱,浓度高抑制作用强);薄壳山核桃根系水浸提液对小麦、大豆种子发芽率、发芽指数、发芽势和活力指数的抑制作用分别依次为:活力指数发芽势发芽指数发芽率和活力指数发芽势发芽率发芽指数;薄壳山核桃根系水浸提液各浓度处理对小麦、大豆幼苗根长、苗高、鲜质量和干质量的化感效应均为:根长苗高鲜质量干质量,其中薄壳山核桃根系水浸提液对2种受体植物幼苗根长均有显著的抑制作用,而对幼苗干、鲜质量的影响则因受体植物种类的不同而不同;薄壳山核桃根系水浸提液对2种受体植物的综合化感效应顺序为:小麦大豆;生长7 d的幼苗体内,SOD活性降低,MDA含量、POD活性和CAT活性与对照相比均随浓度的增加而增加。综合分析认为:小麦对薄壳山核桃根系水浸提液更为敏感。     

鸡眼草水浸提液对4种草坪草的化感作用

为探讨鸡眼草(Kummerowia striata)不同部位、不同浓度水浸提液对高羊茅(Festuca arundinacea)、黑麦草(Lolium perenne)、狗牙根(Cynodon dactylon)、白三叶(Trifolium repens)等4种草坪草的化感效应和作用规律,采用培养皿纸床法,以蒸馏水为对照,研究鸡眼草剪碎的植株、未剪碎的植株、叶、茎、根、地上部分0.012 5、0.025、0.05 g/mL 3个不同浓度的水浸提液对高羊茅、黑麦草、狗牙根、白三叶的种子发芽率、发芽速率、幼根长、幼苗高的化感作用。结果表明,鸡眼草水浸提液对高羊茅、黑麦草、狗牙根、白三叶4种受体植物种子的萌发及幼苗生长均有较强的化感抑制作用,且对种子发芽率作用强弱顺序为:狗牙根白三叶黑麦草高羊茅,对种子发芽速率作用强弱顺序为:黑麦草高羊茅狗牙根白三叶,对幼苗苗高作用强弱顺序为:黑麦草白三叶狗牙根高羊茅,对幼苗根长作用强弱顺序为:白三叶黑麦草狗牙根高羊茅。对4种受体植物的综合化感效应以高羊茅最弱,黑麦草、狗牙根、白三叶较为相近。4种受体植物所受到的抑制作用均随着水浸提液浓度的增加而增强,在同一浓度不同部位水浸提液处理下,叶、整株(剪碎)水浸提液对4种受体植物抑制作用比根、茎、整株(未剪碎)及地上部分水浸提液强。高羊茅、黑麦草、狗牙根3种草坪草受0.05 g/mL鸡眼草叶水浸提液的化感抑制作用最强,白三叶则受0.05 g/mL鸡眼草整株(剪碎)水浸提液的化感抑制作用最强。     

喜马拉雅紫茉莉根水浸提液对五种植物的化感作用研究

以采自西藏林芝地区的藏药植物喜马拉雅紫茉莉为试材,探讨其根部不同浓度(0.0125、0.025、0.05、0.1 g·mL-1)水浸提液对莴苣、绿豆、小麦、萝卜、油菜等5种植物的化感效应。结果表明,随着浸提液浓度的增加,受试植物的种子萌发及幼苗生长均受到不同程度的抑制,植株体内丙二醛含量持续升高,抗氧化酶活性及叶绿素含量逐渐下降,受试植物不同部位对浸提液敏感程度为地下部分>地上部分。另外,5种植物对浸提液敏感程度为莴苣>绿豆>小麦>萝卜>油菜。     

外来入侵植物牛膝菊和野茼蒿水浸提液化感作用的生物测定

采用培养皿滤纸法,以小麦(Triticum aestivum L. )和玉米(Zea mays L. )为实验材料,以种子的发芽率、发芽指数、活力指数以及幼苗的株高和根长为测定指标,结合化感效应指数的综合效应值,对外来入侵植物野茼蒿[Crassocephalum crepidioides (Benth. ) S. Moore]和牛膝菊(Galinsoga parviflora Cav. )茎叶水浸提液的化感活性分别进行了测定.结果表明,随野茼蒿和牛膝菊水浸提液质量浓度(0.01～0.10 g·mL-1)的提高,小麦和玉米种子的发芽率、发芽指数、活力指数以及幼苗的株高和根长总体上逐渐减小;与对照组相比,0.01 g·mL-1牛膝菊水浸提液对小麦的幼苗株高以及玉米的种子发芽率和幼苗株高具有一定的促进作用,但对小麦和玉米的幼苗根长有显著抑制作用;而0.01 g·mL-1野茼蒿水浸提液仅对小麦种子的发芽率略有促进作用.0.04～0.10 g·mL-1野茼蒿和牛膝菊水浸提液对小麦和玉米种子萌发及幼苗生长的各项指标基本上均有显著的抑制作用;野茼蒿和牛膝菊水浸提液对玉米种子萌发和幼苗生长的抑制作用大于小麦.0.01～0.10 g·mL-1野茼蒿和牛膝菊水浸提液对小麦和玉米种子萌发和幼苗生长的化感效应指数的综合效应值均小于0,表现为抑制作用,并随2种植物水浸提液质量浓度的提高综合效应值逐渐降低,且前者的化感效应指数的综合效应值大于后者.研究结果显示,野茼蒿和牛膝菊水浸提液对小麦和玉米的化感活性均表现为抑制作用,且化感作用的强度与水浸提液的质量浓度相关;野茼蒿水浸提液的化感作用效应大于牛膝菊.     

入侵植物野胡萝卜浸提液对4种草坪草的化感效应

【目的】明确入侵植物野胡萝卜水浸提液对4种草坪草的化感效应。【方法】采用培养皿滤纸法,观察记录不同浓度(0、10、20、30、40 g·L^-1)的野胡萝卜根、茎、叶水浸提液对4种草坪草种子萌发的影响,根据化感综合效应指数分析野胡萝卜水浸提液的化感作用。【结果】野胡萝卜不同部位浸提液对受体种子的发芽率、发芽势、发芽指数、活力指数、根长和芽长均有一定的影响。化感综合效应指数表明,随着野胡萝卜浸提液浓度的增加,对白三叶、黑麦草、翦股颖的化感抑制作用均增强,对高羊茅的化感作用表现为“低促高抑”的双重效应。4种草坪草的耐受强弱顺序为:高羊茅＞黑麦草＞翦股颖＞白三叶;野胡萝卜叶浸提液对4种草坪草的化感作用强于根和茎。【结论】入侵植物野胡萝卜浸提液对4种草坪草的化感效应较为显著,在入侵严重地区,可选用耐受力强的草坪草建坪。     

外来红树植物拉关木对乡土种桐花树和正红树的化感作用研究

为了探究外来红树植物拉关木对乡土红树植物的化感作用,该研究观察了不同浓度(0.1、0.3、0.5g·mL~(-1))的拉关木根、叶水浸提液对乡土红树植物桐花树和正红树的胚轴(种子)萌发、幼苗生长及叶片抗氧化酶活性的影响。结果表明:(1)拉关木水浸提液对桐花树种子的成苗率、萌发指数和根长均存在抑制作用,其中对根长的抑制作用随水浸提液浓度的提高而增强。(2)根水浸提液对桐花树幼苗的根长、苗高、生物量等生长指标的影响总体上均表现为低浓度促进,高浓度抑制。(3)拉关木水浸提液对正红树胚轴的萌发率、萌发指数、生长指标均表现为促进作用,且根水浸提液0.1、0.3 g·mL~(-1)处理组的芽长以及根、叶水浸提液0.1、0.3 g·mL~(-1)处理组的生物量显著大于对照组;拉关木水浸提液对正红树幼苗的生物量也表现为促进作用。(4)抗性生理方面,随着拉关木水浸提液浓度的升高,桐花树和正红树幼苗SOD活性降低,正红树幼苗POD活性在根水浸提液0.3 g·mL~(-1)和叶水浸提液0.1 g·mL~(-1)处理组显著高于对照组。以上结果表明,不同乡土植物对拉关木化感作用的敏感性不同,拉关木水浸提液抑制了桐花树的生长,而对正红树的生长则表现出一定程度的促进作用。     

高寒地区白苞筋骨草对几种禾草的化感作用

采用青藏高原“黑土滩”次生毒杂草群落的优势植物——白苞筋骨草（Aerba lupulin）地上部分和地下部分水浸液,对青藏高原高寒地区4种禾草种子萌发、幼苗生长的抑制作用进行了分析。结果表明：白苞筋骨草地上部分水浸液对4种禾草种子萌发和幼苗生长具有显著抑制作用（P<0.05）,地下部分水浸液的化感抑制作用不显著（P>0.05）;4种牧草种子萌发对白苞筋骨草水浸提物敏感性强弱顺序为：垂穗披碱草（Elymus nutans）＞老芒麦（E. sibiricus）＞冷地早熟禾（Poa crymophila）＞中华羊茅 （Festuca sinensis）,禾草幼苗生长对白苞筋骨草水浸液的敏感性强弱顺序为：垂穗披碱草＞中华羊茅＞老芒麦＞冷地早熟禾;整体上,4种牧草对白苞筋骨草化感作用的敏感性强弱顺序为：垂穗披碱草＞老芒麦＞冷地早熟禾＞中华羊茅;4种牧草幼苗生长对白苞筋骨草的水浸液敏感性弱于种子萌发。白苞筋骨草的化感抑制作用是高寒地区毒杂草在退化草地蔓延,并最终形成"黑土滩"次生毒杂草群落的一个因素。     

高寒沙化草地中先锋灌木根系水浸提液对4种高原牧草的化感效应分析

以川西北沙化地生态修复治理过程中2种先锋灌木植物高山红柳(Salix cupularis)和沙棘(Hippophae rhamnoides)为供体植物,中华羊茅(Festuca sinensis)、燕麦(Avena sativa)、垂穗披碱草(Elymus nutans)和老芒麦(E.sibiricus)等4种高原优质牧草为受体植物,比较2种先锋灌木的根系水浸提液,对受体植物种子发芽率、幼苗生长以及抗氧化保护酶活性的化感效应的差异,为先锋灌木选择适宜伴生的经济牧草植物提供理论依据。结果显示:2种灌木根系水浸提液对受试植物生长均具有显著的化感效应,且基本表现出低促高抑的规律。(1)燕麦、中华羊茅、垂穗披碱草和老芒麦种子发芽率在沙棘和高山红柳根系浸提液为10和20g·L~(-1)时均得到显著提高,当浸提液浓度达80g·L~(-1)后基本表现出抑制作用,但只有沙棘浸提液处理下燕麦和中华羊茅达到显著水平。(2)2种根系水浸提液处理下燕麦和中华羊茅幼苗根系生长被完全抑制,但垂穗披碱草只在浓度为80g·L~(-1)时才出现抑制现象;当沙棘根系浸提液为20g·L~(-1)时对燕麦和垂穗披碱草的叶长和鲜重均有显著的促进作用,而高山红柳仅对中华羊茅具有显著促进效应。(3)沙棘根系浸提液为20g·L~(-1)时,对4种受体幼苗体内过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性均有显著或极显著的促进效应;浓度为20和40g·L~(-1)的高山红柳根系浸提液,能极显著提高燕麦和老芒麦的CAT活性以及中华羊茅的SOD活性,但浓度为40g·L~(-1)时对燕麦和垂穗披碱草SOD活性有显著的抑制作用;4种受体植物幼苗MDA含量变化趋势均基本与酶活性吻合,能较好地反映酶活性变化下其受到的氧化胁迫程度。(4)综合化感效应指数(SE)显示,垂穗披碱草对2种灌木根系水浸提液适应性最好,其抑制浓度均为80g·L~(-1);各浓度根系浸提液处理中,高山红柳对燕麦和中华羊茅的促进效应均高于沙棘,但沙棘对垂穗披碱草和老芒麦则表现出更强的促进优势。     

龙柏枝叶水浸提液及其萃取物除草活性的生物测定

采用培养皿滤纸法,以油菜(Brassica campestris L. )、反枝苋(Amaranthus retroflexus L. )、生菜(Lactuca sativa L. var. ramosa Hort. )、番茄(Lycopersicon esculentum Miller)和小麦(Triticum aestivum L. )为供试植物,对龙柏(Sabina chinensis 'Kaizuca')枝叶水浸提液的除草活性进行了生物测定,并以番茄为测定对象,对水浸提液的不同溶剂萃取物的除草活性也进行了生物测定;另外,采用薄层层析法对乙酸乙酯萃取物的除草活性成分进行了初步定性分析.结果显示,在0.05～0.2 g·mL-1质量浓度范围内,龙柏枝叶水浸提液对5种植物的种子萌发及幼苗根长和茎高均有一定的抑制作用,且随质量浓度的提高,抑制作用逐渐增强,其中0.2 g·mL-1水浸提液对5种植物的种子萌发及幼苗根长和茎高的抑制率均在80.00%以上, 对番茄种子萌发及幼苗根长和茎高的抑制率最高, 均达到100.00%.在龙柏枝叶水浸提液的石油醚、乙酸乙酯和水萃取物中,0.01、0.02和0.04 g·mL-1石油醚或乙酸乙酯萃取物以及0.02和0.04 g·mL-1水萃取物对番茄种子萌发及幼苗根长和茎高均有一定的抑制作用,且随质量浓度的降低,抑制率逐渐降低;其中,乙酸乙酯萃取物的抑制作用最强,水萃取物的抑制作用最低.薄层层析显色结果表明,龙柏枝叶水浸提液乙酸乙酯萃取物的主要除草活性成分为酚类成分.     

油蒿(Artemisia ordosica)的化感作用研究

通过对鄂尔多斯高原毛乌素沙地油蒿（Ａｒｔｅｍｉｓｉａ ｏｒｄｏｓｉｃａ）化感作用研究,发现油蒿茎叶的水浸提液对几种受体植物种子的萌发率,幼苗长和根长生长均有不同程度的抑制作用,随水浸提液浓度的增加抑制作用逐步增加;用油蒿茎叶水浸提液进行盆栽试验,受体植物的出苗率,苗高,根长和干物重也受到抑制,苗的形态也与对照有较明显的差异;     

纳米二氧化钛对生菜的生长效应分析

为了阐明纳米二氧化钛颗粒(TiO₂NPs)对生菜(Lactuca sativa)生长的影响，采用自行设计的水培装置探究不同浓度TiO₂NPs (300~1 200 mg/L)下，生菜生长和生理生化指标的变化。结果表明，300 mg/L TiO₂NPs能促进生菜幼苗的根长、茎长、叶表面积、鲜重和干重；随着TiO₂ NPs浓度增大，生菜的生长指标呈现下降趋势，但仍优于对照组。生菜体内的抗氧化酶(SOD、POD)在低TiO₂ NPs浓度(300 mg/L)时，活性明显下降；随着TiO₂ NPs浓度增大，这两种抗氧化酶活性逐渐增强。因此，生菜对TiO₂NPs胁迫具有浓度依赖性，表现为“低促高抑”，且能够通过抗氧化酶系统来减轻TiO₂NPs伤害。     

Effect of plant growth promoting bacterium; Pseudomonas putida UW4 inoculation on phytoremediation efficacy of monoculture and mixed culture of selected plant species for PAH and lead spiked soils

Plant growth promoting bacteria (PGPB) enhanced phytoremediation (PEP) is an attractive remedial strategy for the remediation of polycyclic aromatic hydrocarbon (PAH) and heavy metal (HM) contaminated sites. The effect of PGPB; Pseudomonas putida UW4 inoculation on the phytoremediation efficiency of Medicago sativa, Festuca arundinacea, Lolium perenne, and mixed plants (L. perenne and F. arundinacea) was assessed. This involved two contaminant treatments; “PAH” (phenanthrene; 300?mg·kg^?1, fluoranthene; 200?mg·kg^?1, and benzo[a]pyrene; 5?mg·kg^?1) and “PAH?+?HM” (‘PAH’ treatments +100?mg of Pb/kg). PGPB inoculation significantly enhanced root biomass yield of F. arundinacea in PAH treatment, and the mixed plant shoot biomass and L. perenne root biomass yields of the PAH?+?HM treatment. PGPB significantly enhanced dissipation of phenanthrene and fluoranthene for M. sativa-PAH?+?PGPB treatment and fluoranthene for F. arundinacea-PAH?+?HM?+?PGPB treatment. In others, PGPB inoculation either had no impact or inhibited PAH dissipation. PAH dissipation for the single and mixed plant treatments with PGPB inoculation were not different. The efficiency of PEP is dependent on different factors such as PGPB inoculum biomass, plant species, plant–microbe specificity and type of contaminants. Exploiting PEP technology would require proper understanding of plant tolerance and growth promoting mechanisms, and rhizosphere activities.     

Differential effects of camptothecin and interactions with plant hormones on seed germination and seedling growth

Effects of camptothecin, a naturally occurring alkaloid, on seed germination varied from promotive to inhibitory, depending on the species used. It markedly inhibited seedling root growth but its inhibition of hypocotyl growth varied among species. Camptothecin inhibited GA₃-induced dark germination of lettuce (Lactuca sativa L.) seeds and hypocotyl elongation of seedlings. In contrast to ABA, the camptothecin inhibition of GA₃-induced germination could not be overcome by cytokinin. When seeds were germinated at 29C with a 0.5 h light treatment, little or no germination occurred in the camptothecin treatment, but addition of cytokinin overcame this inhibition.     

An examination of the growth substance activity of vitamin D3

The plant growth activity of vitamin D₃ has been examined using well-established bioassays. Vitamin D₃ was found to promote adventitious root formation in cuttings ofPopulus tremula and to promote the germination of lettuce (Lactuca sativa cv. Grand Rapids) seeds in the absence of light. No other effects were observed typical of plant growth substances.Presented at the Federation of European Societies of Plant Physiology IVth Congress, Strasbourg (1984).     

氮沉降对不同入侵程度加拿大一枝黄花化感作用的影响

为探究全球氮沉降影响外来植物入侵扩张的作用机制,该文通过受控模拟试验,以入侵植物加拿大一枝黄花(Solidago canadensis)为对象,研究了三种氮水平(N0、N5和N12)下五种不同入侵程度(种内及种间竞争)的加拿大一枝黄花凋落叶浸提液对本地植物莴苣(Lactuca sativa)种子萌发和幼苗生长化感作用的影响。结果表明:(1)N0、N5和N12处理下的不同入侵程度加拿大一枝黄花凋落叶浸提液均显著抑制莴苣的萌发和生长,其中N5土壤入侵初期(S1A3)处理浸提液的化感作用最显著,其发芽速度指数、发芽活力指数、根长、株高和叶长比对照分别降低了61%、79%、84%、68%和13%,此时凋落叶中的总酚和总黄酮含量最高,分别为0.48 mg·g^-1和1.50 mg·g^-1。(2)相同氮添加下,入侵程度对加拿大一枝黄花化感作用有显著影响,随着入侵程度的增加,加拿大一枝黄花化感作用显著减弱,入侵初期(S1A3)凋落叶化感作用显著高于入侵后期(S3A1)。(3)相同入侵程度下,氮添加对加拿大一枝黄花化感作用有显著影响,N5处理的加拿大一枝黄花化感作用比N0或N12处理显著增加。(4)氮添加与入侵程度有交互作用,两者共同作用显著影响了莴苣种子的综合化感作用。综上结果表明,氮沉降可能会增强入侵初期加拿大一枝黄花凋落叶对本地植物的化感抑制作用,进一步促进外来植物的成功入侵,为进一步研究加拿大一枝黄花的化感作用及生态防治提供了一定的理论参考。     

Hydrolysis products of glucosinolates in Brassica napus tissues as inhibitors of seed germination

Enzymatic hydrolysis of glucosinolates, a class of compounds found in Brassica species, results in a number of products with potential to inhibit seed germination. To investigate the impact of both volatile and water-soluble allelochemicals, germination bioassays using Lactuca sativa seeds were conducted with root and combined leaf and stem tissues of Brassica napus. Tissues in which glucosinolates were hydrolyzed to remove volatile glucosinolate degradation products were compared with intact tissues and water controls. Only tissues containing glucosinolates produced volatiles that inhibited germination. Volatiles were trapped and identified using GC-MS. Volatiles produced in greater quanitity from intact tissues than from tissues without glucosinolates were almost exclusively glucosinolate hydrolysis products. Water-soluble components also inhibited germination. Chemical analysis of extracts confirmed the presence of glucosinolate hydrolysis products, but indicated the involvement of additional allelochemicals, especially in leaf and stem tissues. Results support the proposal that glucosinolate-containing plant tissues may contribute to reductions in synthetic pesticide use if weed seeds are targeted.Abbreviations ITC isothiocyanates - CN organic cyanides - OZT oxazolidinethione - iRoot intact root tissue - iL&S intact leaf and stem tissue - hRoot hydrolyzed root tissue - hL&S hydrolyzed leaf and stem tissue     

Barium effects inPhaseolus aureus,Cephalandra indica,Canna indica,Beta vulgaris,Triticum aestivum andLactuca sativa

Barium chloride at 0.1 mM concentration inhibited elongation of mungbean (Phaseolus aureus) roots more strongly than elongation of hypocotyls. Root growth was completely inhibited at 80 mM and there was no germination at 100 mM. Respiration rates which were directly proportional to seedling vigour declined at varying degrees at the growth-inhibitory concentrations of BaCl₂. Barium retarded senescence in isolated leaf discs ofCephalandra indica by maintaining the chlorophyll level in darkness. The carotenes were similarly protected from degradation by Ba in darkness whereas xanthophylls were retained both in darkness and light. Ba also protected anthocyanin pigments in the staminode discs ofCanna indica flowers and reduced to a variable extent the leakage of betacyanin pigment fromBeta vulgaris root discs caused by various membrane active chemicals. Applied either alone or in combination with IAA, Ba inhibited cell enlargement in wheat (Triticum aestivum) coleoptile sections. Barium-induced inhibition of lettuce (Lactuca sativa) hypocotyl elongation was largely overcome by GA₃.     

Systematic implications of sesquiterpene lactones in Lactuca species

A chemosystematic study of eleven species from the genus Lactuca (Asteraceae) was performed, based on the distributional data for eight sesquiterpene lactones as diagnostic characters. The lactones were identified in leaf and root extracts by comparison of their HPLC retention times and on-line UV spectra with those of reference compounds. Our results support the status of the section Lactuca, subsection Lactuca as a recognizable group within the genus, although Lactuca aculeata is a distinct species. Moreover, sesquiterpene lactone patterns of Lactuca perennis, Lactuca tatarica, Lactuca indica and Lactuca capensis are also given. It is worth noting that the sesquiterpene lactones are absent from Lactuca tenerrima. The chemosystematic impact of lactucin-type guaianolides and the germacranolide lactuside A is discussed briefly.     

A chlorophyll fluorescence analysis of photosynthetic efficiency, quantum yield and photon energy dissipation in PSII antennae of Lactuca sativa L. leaves exposed to cinnamic acid

This study investigated the effects of cinnamic acid (CA) on growth, biochemical and physiological responses of Lactuca sativa L. CA (0.1, 0.5, 1.0 and 1.5 mM) treatments decreased plant height, root length, leaf and root fresh weight, but it did not affect the leaf water status. CA treatment (1.5 mM) significantly reduced F_v, F_m, photochemical efficiency of PSII (F_v/F_m) and quantum yield of PSII (ΦPSII) photochemistry in L. sativa. The photochemical fluorescence quenching (qP) and non-photochemical quenching (NPQ) were reduced after treatment with 1.5 mM CA. Fraction of photon energy absorbed by PS II antennae trapped by “open” PS II reaction centers (P) was reduced by CA (1.5 mM) while, portion of absorbed photon energy thermally dissipated (D) and photon energy absorbed by PSII antennae and trapped by “closed” PSII reaction centers (E) was increased. Carbon isotope composition ratios (δ¹³C) was less negative (−27.10) in CA (1.5 mM) treated plants as compared to control (−27.61). Carbon isotope discrimination (Δ¹³C) and ratio of intercellular CO₂ concentration (ci/ca) from leaf to air were also less in CA treated plants. CA (1.5 mM) also decreased the leaf protein contents of L. sativa as compared to control.     

盐磷胁迫对木麻黄和台湾相思种子萌发及幼苗生长的影响

恶劣环境下,人工海防林因面临养分胁迫而经营困难。为探讨盐、磷胁迫对主要海防林树种木麻黄和台湾相思种子萌发及生长的影响,该研究分别用不同浓度的NaCl(盐)和KH₂PO₄(磷)溶液处理种子和浇灌幼苗,测定种子萌发和幼苗生长指标。结果表明：(1)高盐胁迫显著抑制种子萌发,对幼苗生长有一定影响,但两种植物影响程度不同;台湾相思种子萌发耐盐性高于木麻黄,前者相对盐害率最大值为23.03%,后者为89.15%;随着盐浓度增加,木麻黄和台湾相思种子的发芽率、发芽势、发芽指数和活力指数均降低,对应最大值分别为38.70%、34.67%、18.70、0.055和76.67%、62.22%、48.46、6.11。(2)两种植物的株高和根长随盐浓度增加而降低,木麻黄和台湾相思株高分别为12.29～6.01 mm和48.27～17.33 mm,根长分别为8.57～1.45 mm和33.41～5.88 mm;台湾相思根、茎、叶生物量及根冠比均随盐浓度的增加逐渐减小,木麻黄各处理差异较小。(3)台湾相思的种子和幼苗较木麻黄更耐低磷环境,二者最适磷浓度存在差异;木麻黄种...