盐胁迫下3种滨海盐生植物的根系生长和分布

我国广大滨海地区的盐土上发育着大量的盐生植物,这些植物的根系对维持土壤稳定性,减小风蚀和水蚀具有重要作用。在水培条件下,针对碱蓬、盐角草和盐地碱蓬3种滨海盐生植物,研究它们在不同盐浓度条件下根系分布的差异。结果表明:一定浓度的盐分可以促进3种盐生植物生长,但较高浓度的盐抑制其生长,特别是对根系生长的抑制作用更大。在同样盐浓度下,盐地碱蓬的生长最快,生物量也最大。在盐分浓度较低时,3种盐生植物的主根长和总根长都有所增加,与对照相比,盐角草增加的幅度较大,但高浓度的盐会抑制根系总长度的增加,其中盐角草较碱蓬和盐地碱蓬抑制的程度轻。盐分对3种植物的根系平均直径没有显著的影响,但有减小的趋势。在水培条件下,碱蓬和盐角草的根系上、中、下部分布的较均匀,而盐地碱蓬的根系中部比上部和下部有显著的增加,盐分对每种植物的根系的分布没有显著的影响。从根系的分布特征可以推断:盐角草比碱蓬和盐地碱蓬具有较强的抗盐性和耐瘠薄能力;碱蓬的耐盐能力较其它两种植物差,盐角草的耐盐性最强。根据3种滨海盐生植物的根系生长和分布特征,证明这3种植物的根系分属于2种功能型,碱蓬是浅根系功能型,盐角草和盐地碱蓬是深根系功能型。根系分布的参数表明3种滨海盐生植物中盐地碱蓬是用来加强土壤稳定性最好的植物。     

NaCl胁迫对3种荒漠植物幼苗叶绿素荧光参数的影响

以生长在荒漠地区的典型盐生植物囊果碱蓬(Suaeda physophora Pall.)、旱生植物梭梭[Haloxylon am-modendron(C.A.Mey.)Bunge]和超旱生植物白梭梭(Haloxylon persicum Bunge ex Boiss.et Buhsee)的幼苗为实验材料,研究了它们在不同NaCl浓度处理下的叶绿素荧光参数变化特征.结果表明:在NaCI胁迫下,同期囊果碱蓬的PSⅡ潜在活性(Fv/Fo)和最大光化学量子产量(Fv/Fm)降低幅度较小,而梭梭和白梭梭则有较明显降低,而且囊果碱蓬显著高于后两者;同期光合量子产量(Yield)和表观光合电子传递速率(ETR)均以囊果碱蓬最大并显著高于其余2种植物,而梭梭与白梭梭之间无显著差异.囊果碱蓬和梭梭的Yield和ETR并不随NaCl浓度的增加而降低;同一植物的荧光参数在各浓度盐处理间无显著差异.在本实验条件下,NaCl胁迫并未使囊果碱蓬的PSⅡ受到明显损伤,其仍能够较正常地吸收光能进行光合作用,对盐分胁迫有较强的忍耐能力;适度的盐渍对囊果碱蓬和梭梭幼苗的生长是有益的;盐胁迫效应主要表现为种间差异,而非处理间差异;叶绿素荧光技术可以有效应用于耐盐植物筛选.     

盐胁迫对翅碱蓬生长和渗透调节物质浓度的影响

盐胁迫环境抑制植物的生长,不同的盐分浓度对植物的抑制伤害存在差异.本文探讨了翅碱蓬(Suaeda heteroptera Kitagawa)对盐生环境的生理生态适应机制,研究其在不同盐浓度下,株高、根长、鲜重、干重等生长指标以及相对含水量、游离脯氨酸、可溶性糖和蛋白质含量的变化情况.结果表明:盐分对翅碱蓬幼苗的抑制作用...     

盐胁迫下囊果碱蓬出苗状况及苗期抗盐性

研究了盐胁迫对囊果碱蓬出苗、幼苗生长、离子积累以及光合放氧速率的影响.囊果碱蓬生长的最适盐浓度在200 mmol/L NaCl左右.高浓度NaCl(400 mmol/L和600 mmol/L)没有显著降低其出苗率,200 mmol/L NaCl对出苗率具有促进作用.400 mmol/L和600 mmol/L NaCl显著降低了光合放氧速率.囊果碱蓬在高浓度NaCl处理下能够维持叶片较高的K+/Na+ 及含水量可能是其适应高盐生境的重要机制.     

8种盐生植物种子萌发特征与NaCl盐度的关系

耐盐植物的选育是盐渍土地生物改良的关键。通过对13个NaCl盐度梯度下，真盐生植物囊果碱蓬、盐地碱蓬、高碱蓬、盐角草、盐爪爪，泌盐植物大叶补血草、耳叶补血草、黄花补血草8种盐生植物的萌发试验，测定其种子发芽率、发芽势、发芽指数和相对盐害率等指标，研究不同NaCl盐度胁迫对其萌发特性的影响。结果表明：低盐度（50 mmol/L）能促进8种盐生植物的萌发；随着盐度的上升，盐角草、盐地碱蓬、囊果碱蓬、高碱蓬表现出较强的萌发耐盐性，发芽势和发芽指数优于其他植物；盐角草的萌发耐盐性最佳，在1000 mmol/L盐度下萌发率仍能达到54.0%。进一步通过S型生长曲线和线性模型分析得出，8种植物为对抗逆境大致分为"快速型"和"缓慢型"两种萌发策略；随盐度的升高，初始萌发时间和萌发高峰时间均不同程度的向后推迟。盐度≤200 mmol/L时，囊果碱蓬的萌发占据优势，其萌发速率大于其他植物，且差异显著；中盐度400 mmol/L左右时，盐地碱蓬和盐角草萌发最快，二者无显著差异；盐度≥600 mmol/L时，盐角草萌发速率较快，相比其他植物差异显著。泌盐植物的萌发耐盐适宜浓度和耐盐极限浓度均低于真盐生植物。8种植物均有作为氯化物为主盐渍土地区生物改良材料的潜力。     

真盐生植物囊果碱蓬(Suaeda physophora)脱水种子子叶叶绿素特征及其对植物萌发阶段适应盐渍环境的生态意义

本研究观察到囊果碱蓬(Suaeda physophora)脱水种子子叶含有深绿色色素, 分别在645和663 nm波长下测定了脱水种子子叶和黑暗中在去离子水半浸没12 h的种子子叶内色素含量及其在400~700 nm波长范围内的光谱吸收特征曲线, 并与囊果碱蓬真叶内的叶绿素光吸收特征曲线进行比较, 结果显示这种色素是叶绿素, 其光吸收特征曲线与真叶叶绿素的几乎完全相同, 表明这种叶绿素具有和真叶叶绿素相近的生理功能. 通过光合能力测定发现, 囊果碱蓬脱水种子吸水6 h后就能进行光合放氧. 用电子显微镜观测了在去离子水和700 mmol/L NaCl溶液中处理1天和10天的囊果碱蓬种子的叶绿体形态, 同时对胚根细胞质膜的受损伤程度进行了组织化学染色观测, 并以同为黎科、且脱水种子子叶中也存在叶绿体的旱生植物白梭梭(Haloxylon persicum)为对照进行同步观测. 结果表明, 相对于非盐生植物白梭梭, 高盐度下囊果碱蓬种子的子叶叶绿体结构、胚根细胞质膜均保持完好, 表现出很强的抗盐能力. 黑暗条件下囊果碱蓬种子在去离子水和700 mmol/L NaCl溶液中的萌发过程是渐进式的, 72~84 h才能达到萌发高峰; 但是在700 mmol/L NaCl溶液中浸泡10天而未萌发的种子移到去离子水中以后的恢复萌发则是爆发式的, 在24 h之内即达到萌发高峰, 并且这些种子具有光合能力. 因此可以推断, 高浓度的盐分对于真盐生植物囊果碱蓬的快速恢复萌发具有激发效应, 这种特性保证了种子在自然条件下能够在早春短暂的、适宜的土壤低盐分条件下迅速萌发; 干燥种子子叶中保留的具有完整结构的叶绿体则可通过光合作用保证萌发了的幼苗迅速生长, 建立种群.     

阜康荒漠植被灌木与半灌木种群生态位的研究

 通过测算三维生态因子梯度上阜康荒漠植被灌木与半灌木种群的生态位宽度和生态位重叠,结果表明;阜康荒漠植被灌木、半灌木按生态位宽度可分成4类,类群Ⅰ包括红砂(Reaumuria soongorica)和梭梭(Haloxylon ammodendron);类群Ⅱ包括白刺(Nitraria sibirica)、盐爪爪(Kalidium foliatum)、囊果碱蓬(Suaeda physophora)、里海盐爪爪(K．caspicum);类群Ⅲ包括多枝柽柳(Tamarix ramosissima)、长穗柽柳(T．elongata)、短穗柽柳(T．laxa)和无叶假木贼(Anabasis aphylla);类群Ⅳ包括黑果枸杞(Lycium ruthenicum)、粗枝猪毛菜(Salsola subcrassa)和盐节木(Halocnemum strobilaceum)。根据生态位重叠矩阵,红砂和梭梭间生态位重叠较大;盐爪爪、囊果碱蓬、里海盐爪爪、多枝柽柳、长穗柽柳间重叠较大;白刺、短穗柽柳、无叶假木贼、黑果枸杞、粗枝猪毛菜和盐节木与其它种的重叠值均较小。     

种植盐地碱蓬改良滨海盐渍土对土壤微生物区系的影响

利用盐生植物盐地碱蓬对天津河口滨海盐碱地进行生物修复,研究了其对土壤微生物区系的影响.结果表明,种植区碱蓬根系土壤的可溶性盐分与对照土壤相比下降了41%（重量法）和37%（电导法）;根系土壤的微生物数量明显增加,其中细菌、放线菌和真菌分别较对照增加了2.3倍、4.3倍和71倍,与对照相比均为显著性差异.根系微生物的耐盐性结果显示,随着土壤盐分的降低,根系微生物生长的最适盐度也随之降低,耐盐性较低的微生物种群已逐渐成为优势种群.系统发育分析表明,枯草杆菌属成为植物修复后土壤中的优势种群.     

KCl和NaCl处理对盐生植物碱蓬幼苗生长和水分代谢的影响

研究了用不同浓度KCl和等浓度NaCl处理的盐生植物碱蓬幼苗水分代谢的变化.结果表明,NaCl处理显著促进碱蓬生长,根吸水增加,含水量高于对照.而相同浓度KCl处理却严重抑制碱蓬生长,含水量显著下降,400 mmol/L的 KCl处理后6 d,地上部分发生萎蔫,尔后死亡.KCl处理伤害碱蓬的原因之一是抑制根系吸水,而对蒸腾速率无显著影响,即水分吸收速率与蒸腾速率比值下降,植株缺水引起伤害.     

新疆呼图壁种牛场地区囊果碱蓬及其群落的生物生态学特性研究

在研究地区 ,囊果碱蓬 (Suaeda physophora)分布在表层 (0～ 2 0 cm)盐分含量为 3.0 %～ 6.0 %的盐土上。囊果碱蓬群落为多汁木本盐柴类荒漠中的一个群系 ,本区记载有 9个群丛。群落总覆盖度为 6%～ 2 5% ,种类组成稀少 ,群落结构简单。囊果碱蓬株高 45～ 60 cm;当年生小枝长 1 2 cm;叶肉汁、条形。侧根发达 ,主要分布在由表层往下土壤中的盐分含量大量减少、水分含量大幅度增加的 2 0～ 60 cm的土壤层内。以冠幅 (长以 X1 表示 ,宽以 X2 表示 )和高 (以 X3 表示 )为参数建立了单株地上部分生物量多元回归模型为 :Y=31 2 .0 0 3.44X1 4.85X2 - 2 .1 6X3 。囊果碱蓬叶有较高的 Na、S含量 ,Na含量高达91 2 55μg· g-1 (9.1 2 6% )。植物不同部位元素含量不同 ,叶和花穗中 K、Na、Mg、S和 P含量最高 ,老枝中含量最低。嫩枝叶水浸出液的盐分含量为 2 3.1 7% ,高于花穗和老枝。植物不同生长季节 ,元素和盐分含量都有所变化     

Strategies for adaptation of Suaeda physophora, Haloxylon ammodendron and Haloxylon persicum to a saline environment during seed-germination stage

BACKGROUND AND AIMS: Germination is very important for plant establishment in arid regions. The strategies taken by halophytes during the seed germination stage to adapt to saline environments in an arid zone were investigated in Suaeda physophora (euhalophyte), Haloxylon ammodendron (xero-halophyte) and Haloxylon persicum (xerophyte). METHODS: Seeds of S. physophora, H. ammodendron and H. persicum were exposed to a range of iso-osmotic NaCl and PEG solutions. Seed germination in, and recovery germination from, high NaCl were recorded. The effects of iso-osmotic NaCl and PEG on seed water uptake and changes in ion content were measured. In addition, the structure of seeds and Na+ distribution in the seed coat and embryos of dry seeds were investigated. KEY RESULTS: The relative increase in fresh weight of germinating seeds was markedly reduced in -2.24 MPa PEG compared with that in -2.24 MPa NaCl, while the opposite trend was found in concentration of K+ during the initial 9 h for all species. Haloxylon ammodendron and S. physophora had a higher recovery germination from -3.13 MPa NaCl compared with H. persicum. Seeds of all species had no endosperm. More Na+ was compartmentalized in the seed coats of the two halophytic species compared with that in the xerophyte H. persicum. CONCLUSIONS: The effect of NaCl on seed germination was due to both osmotic stress and ion toxicity for the three species. High soil salinity and a high content of Na+ in seeds may induce more seeds to remain ungerminated in S. physophora and H. ammodendron. Morphological structure and adaptation to salinity during seed germination may determine the geographical distribution of H. ammodendron and S. physophora in certain saline regions.     

渗透胁迫和外源脱落酸对梭梭幼苗生理特性的影响

水分、渗透胁迫和外源脱落酸（ＡＢＡ）对旱生植物梭梭幼苗的某些生理特性存在显著影响。梭梭幼苗有很强的吸水能力,渗透胁迫下脯氨酸含量增加,其细胞膜相对透性对渗透胁迫不敏感,在脱水过程中具有较强的持水能力,外源ＡＢＡ加强了梭梭幼苗的抗渗透胁迫和抗脱水的能力。     

3种荒漠灌木的用水策略及相关的叶片生理表现

以新疆古尔班通古特沙漠南缘原始盐生旱生荒漠的3种建群灌木多枝柽柳(Ｔamarix ramosissima)、梭梭(Ｈaloxylon ammodendron)和琵琶柴(Reaumuria soongorica)为对象,跟踪自然降雨过程,利用LI-6400光合作用系统和Model 3005植物水分压力审测定光合作用和叶水势的变化,以研究浅层土壤水分条件改变对荒漠灌木主要叶片生理特征的影响;并在原始生境中将植株根系完整地深挖取出,进行根系形态结构调查,以确定此3种灌木根系功能型与用水策略。当浅层土壤分别处在水分充足及匮缺的条件下时．测定3种灌木的光合作用响应曲线和日过程曲线．以及黎明前和止午叶水势,结果表明：浅层土壤水分状况变化时,3种灌木的光合能力均没有显著改变;多枝柽柳的叶水势亦没有明显波动;而梭梭和琵琶柴的叶水势却表现出显著差异。在两种功能型根中,多枝柽柳为深根型,生存和乍理活动的维持主要依赖于地下水;而梭梭和琵琶柴为非深根型植物,主要水源是降水形成的浅层土壤水,其用水策略是根据水分条件行效调节根系和冠层生长,从而维持正常的光合作用。即荒漠灌木在长期适应的过样中．已形成不同的根系功能型和用水策略;叶水势对浅层土壤水分状况变化的种间差异性响应在一定程度上反映了这一点。同时．此3种荒漠灌小通过不同的个体适应策略都能够实现水分平衡和碳收支的有效调节,这主要体现为浅层土壤水分条件变化时光合响应的种间一致性。     

Effect of salinity on seed germination,ion content and photosynthesis of cotyledons in halophytes or xerophyte growing in Central Asia

Aims We investigated the impact of salinity on seed germination, chlorophyll content, chloroplast structure and photosynthesis of the green embryos in desiccated seeds of the xerophyte Haloxylon persicum, xero-halophyte Haloxylon ammodendron and euhalophyte Suaeda physophora.Methods Seeds of H. persicum, H. ammodendron and S. physophora were collected from natural environment in Fukang, Xinjiang province. Pretreatment with 700 mM NaCl was carried out to stimulate the natural 'seed priming'; we analyzed the joint effect of salinity and different species on germination physiology and cotyledonal structure and photosynthetic function changes during germination and recovery stage.Important findings We found that seeds did not suffer ion toxicity for the two halophytes H. ammodendron and S. physophora, as evidenced by the high final germination after ungerminated seeds pretreated with 700 mM NaCl were transferred to distilled water, but the final germination of the xerophyte H. persicum was significantly lower than that of control. The Na + concentration in embryos increased under salinity for all species, while K + concentration decreased by salinity only for H. persicum and H. ammodendron, i.e. the concentration of K + in embryos of H. persicum and H. ammodendron decreased by 36% and 46%, respectively. For all species, whether dry intact seeds or cotyledons of dry seeds imbibed in deionized water and NaCl solution, had high chlorophyll content. Treatment with NaCl also caused chloroplast thylakoids to swell and chlorophyll content to decrease in seeds of H. persicum, but no significant change was observed in the more salt-tolerant species S. physophora and H. ammodendron. Fluorescence measurement showed that 700 mM NaCl decreased the Fv/Fm ratio of cotyledons in seeds for all species, especially for H. persicum and H. ammodendron. Photosynthetic oxygen releasing was detected from the seeds that were moistened with distilled water and 700 mM NaCl for 6 or 24 h and from the seeds that were initially moistened with 700 mM NaCl in darkness for 10 days, then transferred to distilled water for another 6 and 24 h. The results indicated that the chlorophyll in cotyledon of desiccated seed had photosynthetic function in early germination stage, even under high-saline condition. In addition, the photosynthesis of chlorophyll in the embryonic cotyledons of desiccated seeds during germination was similar to that in leaves of young seedlings for all species. In conclusion, the chloroplasts of the two halophytes were more salt resistant compared with the xerophyte H. persicum. The photosynthetic function of chlorophyll in cotyledons of mature seeds may be ecologically important for seedling development in early stage for plants growing in extremely saline or arid environments.     

不同苗龄梭梭根系分泌物组分分析

以梭梭幼苗为供试材料,采用循环灌溉技术收集梭梭不同苗龄近自然状态下根系分泌物,利用气相色谱质谱联用技术分析了根系分泌物的组分和含量,探讨梭梭幼苗不同发育时期根系分泌物的差异.实验结果表明:不同苗龄梭梭幼苗根系分泌物化合物的种类组成相似,主要由酚醌类、醛酮类、醇类、有机酸类、酯类和胺类化合物组成;30 d梭梭幼苗根系分泌物主要以有机酸和酯类化合物为主,占梭梭幼苗根系分泌物总量的81.57%;60 d梭梭幼苗根系分泌物主要以酯类和含氮化合物为主,占梭梭幼苗根系分泌物总量的65.08%.     

Significance of Na<Superscript>+</Superscript> and K<Superscript>+</Superscript> for Sustained Hydration of Organ Tissues in Ecologically Distinct Halophytes of the Family Chenopodiaceae

The contents of Na⁺, K⁺, water, and dry matter were measured in leaves and roots of euhalophytes Salicornia europaea L. and Climacoptera lanata (Pall.) Botsch featuring succulent and xeromorphic cell structures, respectively, as well as in saltbush Atriplex micrantha C.A. Mey, a halophyte having bladder-like salt glands on their leaves. All three species were able to accumulate Na⁺ in their tissues. The Na⁺ content in organs increased with elevation of NaCl concentration in the substrate, the concentrations of Na⁺ being higher in leaves than in roots. When these halophytes were grown on a NaCl-free substrate, a trend toward K⁺ accumulation was observed and was better pronounced in leaves than in roots. Particularly high K⁺ concentrations were accumulated in Salicornia leaves. There were no principal differences in the partitioning of Na⁺ and K⁺ between organs of three halophyte species representing different ecological groups. At all substrate concentrations of NaCl, the total content of Na⁺ and K⁺ in leaves was higher than in roots. This distribution pattern persisted in Atriplex possessing salt glands, as well as in euhalophytes Salicornia and Climacoptera. The physiological significance of such universal pattern of ion accumulation and distribution among organs in halophytes is related to the necessity of water absorption by roots, its transport to shoots, and maintenance of sufficient cell water content in all organs under high soil salinity.     

塔克拉玛干沙漠南缘三种防护林植物根系构型及其生态适应策略

采用全根挖掘法挖取塔克拉玛干沙漠南缘3种主要防护林植物种——多枝柽柳(Tamarix ramosissima)、梭梭(Haloxylon ammodendron)和新疆杨(Populus albavar. pyramidalis)成年植株根系, 测定并分析了根系构型及其拓扑结构。结果表明: 1)多枝柽柳和梭梭的根系趋向于鱼尾状分支结构, 新疆杨根系为叉状分支结构, 根系分支结构的差异使其资源获取能力和对环境的适应能力有所差异; 2)三种植物最小的根系平均连接长度为33.67 cm, 多枝柽柳和梭梭的根系连接长度大于新疆杨, 增加连接长度对植物在资源贫瘠的沙质土壤环境的生存有利; 3)新疆杨的根系分支率显著高于多枝柽柳和梭梭, 但其对干旱的适应性不如多枝柽柳和梭梭。4)三种植物根系分支均遵循Leonardo da Vinci法则, 且不受根系直径的约束。三种防护林植物在水、养资源获取与土壤空间拓展方面具有差异性, 表明在相似的极端干旱环境中3种植物采取了不同的生态适应策略。     

Ion-exchange properties of cell walls of Spinacia oleracea L. roots under different environmental salt conditions

Ion-exchange properties of the polymeric matrix of cell walls isolated from roots of 55-day-old Spinacia oleracea L. (Matador cv.) plants grown in nutrient solution in the presence of 0.5, 150, and 250 mM NaCl and from roots of Suaeda altissima L. Pall plants of the same age grown in the presence of 0.5 and 250 mM NaCl were studied. The ion-exchange capacity of the spinach cell walls was determined at pH values from 2 to 12 and different ionic strength of the solution (10 and 250 mM NaCl). In the structure of the root cell walls, four types of ionogenic groups were found: amine, two types of carboxyl (the first being galacturonic acid residue), and phenolic groups. The content of each type of group and their ionization constants were evaluated. The ion-exchange properties of spinach and the halophyte Suaeda altissima L. Pall were compared, and the qualitative composition of the ion-exchange groups in the cell walls of roots of these plants appeared to be the same and not depend on conditions of the root nutrition. The content of carboxyl groups of polygalacturonic acid changed in the cell walls of the glycophyte and halophyte depending on the salt concentration in the medium. These changes in the composition of functional groups of the cell wall polymers seemed to be a response of these plants to salt and were more pronounced in the halophyte. A sharp increase in the NaCl concentration in the medium caused a decrease in pH in the extracellular water space as a result of exchange reactions between sodium ions entering from the external solution and protons of carboxyl groups of the cell walls. The findings are discussed from the standpoint of involvement of root cell walls of different plant species in response to salinity.     

Studies on Chromosome Numbers and Anatomy of Young Branches of Calligonum of Xinjiang in Relation to the Evolution of Some Species of the Genus

There are more than 20 species of Calligonum in China, of which 17 are known from Xinjiang. They are divided into four sections. This paper aims to study the evolutionary relations of some species of Calligonum in Xinjiang. The chromosome numbers of 13 species and the anatomic structures of young branch of 8 species have been examined. Among 13 species, the, basic chromosome number x=9.9 species are diploids. 4 species are tetraploids. The evolutionary relations of these plants are arranged as follows: Section Calligonum (Fisch. et Mey.) Borszcz. 1. C. junceum (Fisch. et Mey.) Litv. Section Pterococcus (Pall.) Borszcz. 2. C. leucocladum (Schrenk) Bge. 3. C. aphyllum (Pall.) Gürke. 4. C. rubicundum Bge. Section Calligonum ,. 5. C. cordatum Eug. Kor. 6. C. densum Borszcz. 7. C. klementzii A. Los. Section Medusa Sosk et Alexandra 8. C. mongolicum Turcz. 9. C. pumilum A. Los. 10. C. ebi-nuricum Ivanova 11. C. arborescens Litv. 12. C. caput-medusae Schrenk 13.C. roborovskii A. Los.