高寒草甸矮生嵩草不同根序解剖结构对生境干旱化的响应

植物根系由不同根序组成,然而,它们的解剖结构对生境干旱化的响应是否一致尚不清楚。本研究于藏东南东达山矮生嵩草(Kobresia humilis)高寒草甸沿生境干旱化梯度设置6个样方,采集矮生嵩草根系。采用石蜡切片法,运用方差分析和主成分分析,比较不同土壤水分生境中矮生嵩草一、二级根序解剖结构的差异及可塑性强弱。结果表明：一、二级根序间解剖结构组成无明显差异,其中横切面表皮细胞近似长方形,排列紧密,面积较大(87.6～126.0μm²);一、二级根序解剖结构对生境干旱化的响应不一致,一级根中表皮细胞面积和厚度、皮层厚度(含厚壁组织与薄壁组织)均与土壤含水率呈显著负相关,而二级根呈显著正相关(P<0.05);一级根表皮占径比在土壤水分梯度间的差异显著,其他解剖结构差异不显著,二级根解剖结构(除皮层厚壁组织外)的占径比在土壤水分梯度间均存在显著差异;一级根皮层薄壁组织厚度可塑性最强,皮层厚壁组织厚度可塑性最弱;二级根横切面面积可塑性最强,中柱面积可塑性最弱。总之,矮生嵩草根系表皮、皮层解剖结构对土壤水分梯度变化的可塑性强,但不同根序解剖结构对生境干旱化的响应机制不...     

西藏东达山3种嵩草属植物气孔特征沿海拔的变化

嵩草属(Kobresia)植物是藏东南高山草甸的优势种和建群种,对该区畜牧业发展和维持生态系统平衡起着重要作用。选择西藏左贡县东达山为研究地点,从林线开始,海拔每升高约100m设置1个样带直至高山草甸分布边缘,共8个样带,调查各样带中物种的组成及盖度,并依据相对盖度和相对频度计算3种嵩草植物矮生嵩草(K.humilis)、线叶嵩草(K.capillifolia)和大花嵩草(K.macrantha)在群落中的重要值,同时取样观察它们叶片远、近轴面表皮细胞形态,测量气孔长度及保卫细胞宽度,计算气孔密度,探讨嵩草属植物对海拔梯度的适应性。结果表明:(1)3种嵩草属植物叶表皮细胞均呈波浪状,气孔器仅分布于远轴面,近轴面无气孔器分布。(2)3种嵩草属植物气孔密度沿海拔梯度的变化均呈单峰曲线分布格局,且在海拔4 537m样带处达到最大值,并表现为矮生嵩草(777.6个/mm2)线叶嵩草(476.4个/mm2)大花嵩草(414.3个/mm2)。(3)随海拔的增加,矮生嵩草和线叶嵩草气孔长度显著增大(P0.05),而保卫细胞宽度显著减小;但大花嵩草气孔长度随海拔的升高而显著减小,保卫细胞宽度基本保持不变。(4)矮生嵩草和线叶嵩草气孔密度、长度和保卫细胞宽度与海拔梯度均显著相关,气孔特征对海拔梯度变化的敏感程度高,与其在群落中重要值高的分布特征一致;而大花嵩草仅气孔密度和长度与海拔梯度显著相关,气孔特征对海拔梯度变化的敏感性低,与其在群落中重要值低的分布特征一致;嵩草属植物气孔密度、长度和保护细胞宽度与海拔梯度之间的相关性,反映出它们在海拔梯度上对生境的适应程度。可见,3种嵩草属植物气孔特征对海拔梯度上生境变化的适应性不同,从而影响它们在群落中的分布范围和物种优势度,其中矮生嵩草和线叶嵩草对环境变化敏感,而大花嵩草对环境变化相对不敏感;保卫细胞宽度与气孔长度同样对植物适应环境变化起重要作用。     

中国嵩草属植物地理分布模式和适应的气候特征

为了明确嵩草属(Kobresia)植物分布与气候要素的关系, 收集了嵩草属植物地理分布资料和气象台站气候数据, 应用ArcGIS软件及SPSS软件中的聚类分析方法, 分析了嵩草属植物地理分布模式和适应的气候特征。结果显示: 嵩草属植物分布在青藏高原、西北、华北和东北部分地区, 广泛分布13种, 间断分布10种, 分布海拔为1 400-5 000 m, 经度和纬度范围分别为81-112° E和23-46° N。嵩草属植物适应的气候要素平均值范围: 年生物学温度为4-19 ℃, 年平均气温为0-20 ℃, 年平均最高气温为7-28 ℃, 年平均最低气温为-6-16 ℃, 极端最高气温为25-40 ℃, 极端最低气温为-37.0-0.0 ℃, 1月和7月平均气温分别为-14-13 ℃和11-24 ℃, 1月和7月最高气温分别为-7-23 ℃和18-30 ℃, 1月和7月最低气温分别为-22-7 ℃和5-20 ℃, 春夏秋冬季气温分别为-4-19 ℃、9-23 ℃、6-21 ℃和-11-15 ℃, 温暖指数为23-159 ℃, 寒冷指数为-36-0 ℃, 年降水量为154-1 500 mm, 春夏秋冬降水量分别为19-135 mm、53-662 mm、48-545 mm和5-92 mm, Holdridge潜在蒸散量为261-1 100 mm, Thornthwaite潜在蒸发量为399-895 mm, 干燥度为167-786, 湿润指数为179-816, 4-10月日照时数为990-2 100 h。在热量要素平均值较低和中等、降水量与干燥湿润度平均值中等或辐射时数平均值较高范围下分布种数较多。嵩草属植物适应的气候要素极值, 年平均气温最小最大值范围为-6-21 ℃, 年平均最低气温最小值最高气温最大值范围为-12-28 ℃, 极端最低气温最小值最高气温最大值范围为-48-42 ℃, 最冷最热月气温范围为-32-33 ℃, 冬夏季最低最高气温范围为-20-25 ℃, 降水量最小最大值范围为15-1 800 mm, 干燥度最小最大值范围为7-890, 日照时数最小最大值范围为701-2 300 h。在热量要素极值较低、降水量及干燥度极值中等或日照时数极值较大范围下分布种数较多。说明嵩草属植物主要适应于低温亚湿润型和中温湿润型气候。     

干旱区叶片形态特征与植物响应和适应的关系

叶片形态是指示植物适应特定环境的重要指标。由于植物叶片形态不仅对时空环境变化具有极强的敏感性和可塑性, 而且能够通过叶片形态的调整调节自身的生存适应能力, 所以叶片形态学研究一直是植物生理及植物生态学研究中的热点。该文在总结前人叶片形态学研究成果的基础上, 探索建立了简单的叶片形态指标分类体系; 结合物质能量交换的物理学原理, 回顾总结了叶片表观形态变化与叶片物质能量交换之间的相关关系; 应用叶片形态影响物质能量交换的物理学原理, 重点分析了干旱区植物叶片表观形态对低水分环境、高辐射(或高温)的响应与适应特征; 最后, 在回顾分析的基础上, 对叶片形态研究中存在的几个问题进行了讨论。     

新疆四种补血草属植物叶片的解剖学研究

利用叶片离析法和石蜡切片法研究了补血草属4种植物叶片的形态结构。结果表明:(1)4种植物的叶片有许多共同的结构适应特征,表皮细胞排列紧密,表面有厚的角质层;气孔类型均为不等型,气孔位置为平置或略微下陷;上下表皮还具有多细胞构成的盐腺;栅栏组织发达,多为等面叶;存在粘液细胞和单宁细胞;机械组织和维管组织都不发达等。(2)不同种间有不同的结构适应特征,如表皮细胞的形状、大小、垂周壁饰样,气孔密度,盐腺密度,叶片厚度和栅栏组织厚度等。通过叶的结构特征反映出盐生植物与旱生植物的不同。     

2种补血草属植物幼苗对NaCl胁迫的生理响应

以盐生植物大叶补血草和黄花补血草为实验材料,研究了NaCl胁迫对其幼苗叶绿素、可溶性蛋白、丙二醛含量等的影响,探讨这些生理指标的变化与补血草耐盐性的关系。结果表明,150mmol/LNaCl胁迫均使大叶补血草和黄花补血草幼苗叶片的叶绿素a(Chla)、叶绿素b(Chlb)和叶绿素总量降低,而过氧化氢(H2O2)和丙二醛(MDA)含量增加,且这种胁迫效应随处理时间的延长而增强,在相同胁迫时间段,大叶补血草各指标的减少或增加幅度明显大于黄花补血草;NaCl胁迫使大叶补血草叶片可溶性蛋白含量降低,却使黄花补血草可溶性蛋白含量增加。表明,NaCl胁迫对大叶补血草的伤害更大,黄花补血草的耐盐性可能强于大叶补血草。     

2种补血草属植物幼苗对NaCI胁迫的生理响应

以盐生植物大叶补血草和黄花补血草为实验材料,研究了NaCI胁迫对其幼苗叶绿素、可溶性蛋白、丙二醛含量等的影响,探讨这些生理指标的变化与补血草耐盐性的关系。结果表明,150mmol／LNaCI胁迫均使大叶补血草和黄花补血草幼苗叶片的叶绿素a（Chla）、叶绿素b（Chlb）和叶绿素总量降低,而过氧化氢（Hzoz）和丙二醛（MDA）含量增加,且这种胁迫效应随处理时间的延长而增强,在相同胁迫时间段,大叶补血草各指标的减少或增加幅度明显大于黄花补血草;NaCI胁迫使大叶补血草叶片可溶性蛋白含量降低,却使黄花补血草可溶性蛋白含量增加。表明,NaCI胁迫对大叶补血草的伤害更大,黄花补血草的耐盐性可能强于大叶补血草。     

狗尾草属5种植物叶片的形态特征

为了解狗尾草属(Setaria Beauv.)植物的叶片形态特征,采用石蜡切片法和徒手切片法观察5 种狗尾草属植物的叶片形态结构。结果表明,5 种狗尾草属植物叶表皮的解剖特征较一致,叶表皮细胞长度、气孔器大小、叶厚、角质层厚度等性状在种间存在显著差异,其中长细胞形状、垂周壁深浅、气孔器副卫细胞的形状和刺毛数量可以用来区分种类。叶片性状的相关分析表明,叶片气孔密度与气孔长度以及气孔宽度呈显著负相关,泡状细胞厚度与角质层厚度以及上表皮厚度呈显著正相关。根据禾本科叶表皮特征的演化趋势,狗尾草(S. viridis)最原始,金色狗尾草(S. glauca)和大狗尾草(S. faberii)较进化,皱叶狗尾草(S.plicata)和莩草(S. chondrachne)最高级。这些为狗尾草属植物分类学和系统演化关系提供资料。     

稻属三种植物叶片下表皮的形态比较

稻属有20多种,其中3种和其他物种明显不同.Oryza eichingeri被认为在亚洲和非洲间断分布;O. officinalis和O punctata被证明同时含有二倍体和四倍体.为了识别种内微形态差异,利用光镜和扫描电镜,对这3个物种的成熟叶片下表皮进行了观察.结果表明,O. eichingeri的叶脉长细胞乳突形状在种内是不一致的,除了斯里兰卡地理宗具有的瘤状乳突外,乌千达地理宗还具有长条状的乳突;同样,种内多样性也存在于O. officinalis和O.punctata内,特别存在于它们不同倍性的细胞型间.在D officinalis中,四倍体有粒状气孔器外围乳突和脉带表皮毛较少,二倍体细胞型具有三角形拱状排列的气孔器外围乳突和较密集的脉带表皮毛;而在O. punctata中,和四倍体相比,二倍体具有小的长细胞表面乳突和低密度分布的气孔.这些稳定的差异为3种植物的种内鉴定和分类修订提供了新的证据.     

安徽产两种山罗花属植物及其居群叶的微形态比较

利用离析法、扫描电镜和石蜡切片法对安徽产2种3居群山罗花属植物的叶进行了微形态比较研究,结果表明：该属植物叶表皮细胞形状为不规则形,垂周壁呈波状、深波状至重波状;表皮细胞内含叶绿体;角质层具条状纹饰;表皮上有表皮毛和腺毛分布,扫描电镜下表皮毛具瘤状突起的纹饰;栅栏组织只有1层,排列比较疏松,海绵组织有发达的胞间隙;气孔器多为无规则型,极少数仅有一个副卫细胞,仅分布于下表皮,扫描电镜下气孔外拱盖内缘近光滑或浅波状。2种植物在垂周壁式样、表皮毛密度、气孔器长宽比、栅栏组织和海绵组织的厚度比以及中脉的结构特征等具有明显的差异,而山罗花3居群间的差异不明显。     

Architecture of Clonal Plants and Morphological Responses to Habitat Heterogeneity

The phalanx and querilla are two extreme architectures. There should be a continuum of interim architecture between phalanx and querilla. The author gives an index describing the continuum v=ln /Inn( ≤v≤1), and discusses the response of spacer length to habitat patchy quality.     

不同耐盐性药用甘草幼苗根对Na~+的响应及其维管组织变化

以甘草属2种耐盐植物胀果甘草、乌拉尔甘草为材料,用不同浓度(50、100、150、200、250mmol·L-1)NaCl处理幼苗21d后,分析其生物量和根、茎、叶中的Na+、K+含量以及K+/Na+,计算根的离子选择吸收和运输系数,并应用光学显微镜观察比较二者的维管组织结构变化,以揭示2种药用甘草幼苗根对Na+的响应及其维管组织结构的变化特征,探讨甘草的耐盐机理。结果表明:(1)NaCl胁迫使2种甘草幼苗生物量均下降,在NaCl浓度为250mmol·L-1时,胀果甘草、乌拉尔甘草幼苗生物量分别是对照的53.34%、46.21%,胀果甘草耐盐性强于乌拉尔甘草。(2)随着NaCl浓度上升,2种甘草根积累的Na+显著增多,其中胀果甘草在所有盐处理下,根Na+含量均高于其它器官,说明其根对吸收的Na+具有显著截留效应;而乌拉尔甘草只在0~150mmol·L-1 NaCl范围内,根Na+含量显著高于叶片,当NaCl为200、250mmol·L-1时,叶片Na+含量显著高于根,说明乌拉尔甘草根对Na+的截留能力有限。(3)在相同盐处理下,胀果甘草离子选择吸收系数SAK,Na、离子运输系数STK,Na均大于乌拉尔甘草,胀果甘草根抑制Na+、促进K+向地上部运输的能力强于乌拉尔甘草。(4)乌拉尔甘草在NaCl为150、200mmol·L-1、胀果甘草在250mmol·L-1时,根结构对盐胁迫产生应激性响应,维管组织比例显著上升,有助于提高根向上的运输能力,减少盐害。研究表明,2种药用甘草根对Na+截留作用和向上运输时促K+抑Na+能力的差异,是导致其耐盐能力不同的主要原因,根对Na+的积累和截留作用的差异与根的结构响应相吻合,能较好地解释二者的耐盐性差异。     

3种阴生地被植物对SO_2胁迫的生理响应及净化能力

该研究以3种阴生地被植物麦冬、虎耳草和紫萼玉簪为研究材料,采用人工模拟熏气方法,测定不同浓度(5.71,11.43,17.14,22.86mg·m~(-3))SO_2胁迫下参试植物的外观受害症状,以及膜质过氧化、保护酶活性、渗透调节物质等生理指标,以叶片吸硫量比较3种植物的净化能力,并采用模糊数学隶属函数与主成分分析法对其抗SO_2能力进行综合评价。结果显示:(1)随着SO_2熏气浓度的升高,3种植物的叶片都有不同程度的受害症状,叶片叶绿素含量、汁液pH值和相对含水量下降,丙二醛含量、叶片相对电导率、可溶性糖、游离脯氨酸含量上升,且其SOD和CAT活性显著增强。(2)隶属函数法和主成分分析法综合评定结果显示,3种地被植物对SO_2抗性能力表现为:麦冬紫萼玉簪虎耳草,与叶片受伤害症状和叶液pH值下降的顺序相反,说明这2个指标可作为简单可行的评价SO_2抗性的重要鉴定指标。(3)3种植物均有一定的SO_2净化能力,其强弱顺序为虎耳草麦冬紫萼玉簪。研究表明,3种阴生地被植物都能够在SO_2胁迫下提高其保护酶活性和渗透调节物质含量,增强其抗硫胁迫和SO_2吸收能力,并以麦冬对SO_2抗性最强,虎耳草对SO_2的吸收能力最强;该试验中最低参试SO_2浓度远远高于城市大气中的实际SO_2浓度,在试验环境下3种阴生植物再都未呈现伤害症状,说明吸收硫能力强的虎耳草和麦冬可以在SO_2污染严重的林下区域大面积应用推广。     

Responses of root length/leaf area ratio and specific root length of an understory herb, Pteridophyllum racemosum, to increases in irradiance

The understory evergreen perennial Pteridophyllum racemosum Sieb. et Zucc. (Papaveraceae) has the ability to increase root mass per unit transpiring leaf area (RMA) if irradiance increases gradually over several years. In this study, we examined how P. racemosum changes its root length/leaf area ratio and specific root length when the species encounters abrupt increases in irradiance, such as sudden and unexpected canopy openings. Plants were transplanted from a low light condition in a subalpine wave-regenerating forest (photon flux density on the forest floor relative to the full sun (RPFD) was 2.7%) to a high light condition in a glasshouse (30% RPFD) (LH treatment). Transplantation from the low light condition in the forest to a low light condition in the glasshouse (LL) and transplantation from a high light condition in the forest (33% RPFD) to a high light condition in the glasshouse (HH) were also conducted as controls. Compared to the LL plants, the LH plants exhibited significant increases in RMA and root length/leaf area ratio from 30 to 70 days after transplantation. On the other hand, the effect of increased irradiance on specific root length (SRL) was weak, and both the LL and LH plants showed increased SRL from 30 to 70 days after transplantation. Increased SRL results from longer root length per unit construction cost. We concluded that increased root length/leaf area ratio of P. racemosum in response to abrupt increases in irradiance was caused by a combination of enhanced carbon allocation to roots with increased SRL.     

Response of Growth Dynamics of Two Spring Geophytes to Light Regime in a Lime-Beech Forest

Blomaee accumulation, leaf longevity and growth rate of two spring forest geophytes, Scllla blfolla L. and Arum maculatum L. were estimated separately for three size groups within each population of these species. Despite the differences in leaf longevity, both species showed a similar pattern of blomass accumulation In relation to their phenologles and reproductive demands. Eco-physlological acclimation to changing light environment was assumed through photosynthetic parameters and dynamics of leaf area Index In the predominant size group of each species. A light response curve was measured under natural light for each species through the continuum of Its phenology to quantify the photosynthetic photon flux density at light saturation, light-saturated photosynthetic rate, light compensation point, and dark respiration. Light-saturated assimilation per leaf area basis, dark respiration rate and light compensation points were significantly higher in S. blfolla relative to A. maculatum. However, the acclimation of photosynthesis that would respond to light changes in environment was not found in S. bifolla. In contrast, In A. maculatum a marked shift In the light dependence of photosynthesis through the season was noticed, which resulted In a strong photosynthetic acclimation to the low-light conditions. Accompanied by significant leaf area Index, this efficient low-light photosynthesis enabled greater leaf longevity, and consequently longer accumulative period to A. maculatum. From the different parameters that we determined （both photosynthetic acclimation and growth strategy） it would appear that these species belong to two distinct subgroups： S. blfolla to the early and A. maculatum to the late vernals.     

敦煌阳关湿地芦苇叶性状对土壤水分的响应

为了了解干旱区湿地不同水分梯度下芦苇叶性状的构建模式及对不同水分环境的适应策略差异性,以敦煌阳关渥洼池湿地植物芦苇(Phragmites australis)为研究对象,分析不同水分梯度下芦苇叶性状对土壤水分的响应。结果表明:(1)低水分梯度下的叶厚度(LT)和叶片磷含量(LPC)显著高于中、高水分梯度(P0.05),高水分梯度下的叶碳含量(LCC)也显著高于中、低水分梯度(P0.05)。(2)芦苇叶性状之间的关系也因水分的变化而有所不同。就整体而言,叶片碳含量与叶干物质含量(LDMC)极显著正相关(P0.01);叶厚度与叶片磷含量极显著正相关(P0.01),比叶面积(SLA)与叶氮含量(LNC)极显著正相关(P0.01)、与叶碳氮比(C/N)极显著负相关(P0.01)。(3)在水分作为限制因素的条件下,叶片碳含量与比叶面积对水分的响应最为突出。土壤含水量与叶厚度、叶碳含量和叶片磷含量均显著负相关(P0.05)。芦苇在低水分环境下采取高收入低投入的积极型生存策略,高水分下则采取低获取高消耗的保守型生存策略,说明了芦苇在适应异质生境的自我调节机制。     

Na^＋ and Water Uptake in Relation to the Radial Reflection Coefficient of Root in Arrowleaf Saltbush Under Salt Stress

The response of halophyte arrowleaf saltbush (Atriplex triangularis Willd) plants to a gradient of salt stress were investigated with hydroponically cultured seedlings. Under salt stress, both the Na+ uptake into root xylem and negative pressures in xylem vessels increased with the elevation of salinity (up to 500 mol/m3) in the root environment. However, the increment in negative pressures in root xylem far from matches the decrease in the osmotic potential of the root bathing solutions, even when the osmotic potential of xylem sap is taken into consideration. The total water potential of xylem sap in arrowleaf saltbush roots was close to the osmotic potential of root bathing solutions when the salt stress was low, but a progressively increased gap between the water potential of xylem sap and the osmotic potential of root bathing solutions was observed when the salinity in the root environment was enhanced. The maximum gap was 1.4 MPa at a salinity level of 500 mol/m3 without apparent dehydration of the tested plants. This discrepancy could not be explained with the current theories in plant physiology. The radial reflection coefficient of root in arrowleaf saltbush decreased with the enhanced salt stress was and accompanied by an increase in the Na+ uptake into xylem sap. However, the relative Na+ in xylem exudates based on the corresponding NaCl concentration in the root bathing solutions showed a tendency of decrease. The results showed that the reduction in the radial reflection coefficient of roots in the arrowleaf saltbush did not lead to a mass influx of NaCl into xylem when the radial reflection coefficient of the root was considerably small; and that arrowleaf saltbush could use small xylem pressures to counterbalance the salt stresses, either with the uptake of large amounts of salt, or with the development of xylem pressures dangerously negative. This strategy could be one of the mechanisms behind the high resistance of arrowleaf saltbush plants to salt stress.     

Domain exchange between isoforms of ferredoxin-NADP+ reductase produces a functional enzyme

Two isoforms of ferredoxin-NADP⁺ reductase (FNR) exist in higher plants, the leaf (or photosynthetic) and the root (or non-photosynthetic) isoform, which have 48% amino acid sequence identity and display specific structural and functional features. With the aim to gain further insight into the structure–function relationship of this enzyme, we designed two novel chimeric flavoenzymes by swapping the structural domains between the leaf and the root isoforms. Characterization of the chimeras would allow dissection of the contribution of the individual domains to catalysis. The chimera obtained by grafting together the FAD-binding domain of the root-isoform and the NADP-binding domain of the leaf-isoform was inactive when expressed in Escherichia coli. On the other hand, the chimera assembled in the opposite way (leaf FAD-binding domain and root NADP-binding domain) was functional and was produced in the bacterial host to a level threefold higher than that of the parent enzymes. The protein was purified and found to be as stable as the natural isoforms. Limited proteolysis excluded the presence in the chimera of misfolded regions. The affinity of the chimera for ferredoxin I (Fd I) was similar to that of the leaf isoform, although interprotein electron-transfer was partially impaired. As occurs with the root isoform, the chimera bound NADP⁺ with high affinity, while spectroscopic evidence suggested that the conformation adopted by the nicotinamide moiety bound to the chimera was similar to that observed in the leaf enzyme. Interestingly, the chimera, by combining favorable features from both parent isoforms, acquired a catalytic efficiency (k_cat/K_m), as an NADPH-dependent diaphorase, higher than those of both the root (～2-fold) and the leaf enzyme (～5-fold). Thus, molecular breeding between isozymes has improved the catalytic properties of FNR.     

5种卫矛属植物对低温胁迫的生理响应及抗寒性评价

以5种卫矛属树种(品系)当年生充分休眠离体带叶枝条为试材,在高低温湿热试验箱内进行0℃、-10℃、-20℃和-30℃共4个梯度低温胁迫处理,考察其叶片解剖结构以及细胞膜透性、渗透调节物质、保护酶活性等生理指标的低温响应特征,并结合隶属函数分析方法综合评价5种卫矛属植物抗寒性。结果表明:(1)‘北海道黄杨6号’叶片有3层紧密的栅栏组织,北海道黄杨、胶州卫矛和大叶黄杨叶片有2层紧密、1层相对疏松的栅栏组织,扶芳藤叶片则只有2层排列紧密的栅栏组织;5个树种叶片组织紧密度表现为‘北海道黄杨6号’北海道黄杨胶州卫矛大叶黄杨扶芳藤。(2)通过Logistic方程拟合叶片相对电导率随温度的变化,获得5种卫矛树种的半致死温度(LT_(50))由低到高依次为‘北海道黄杨6号’(-19.69℃)、北海道黄杨(-17.41℃)、胶州卫矛(-16.03℃)、大叶黄杨(-13.33℃)、扶芳藤(-10.45℃)。(3)各树种叶片渗透调节物质含量随胁迫温度的降低而持续增加,在-30℃低温时,叶片可溶性糖含量以‘北海道黄杨6号’和北海道黄杨的增幅最大,可溶性蛋白含量以胶州卫矛和大叶黄杨增幅最大,但两者含量均以扶芳藤增幅最小。(4)各树种叶片抗氧化酶活性均随胁迫温度的降低而先升高后降低,大叶黄杨和扶芳藤叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、多酚氧化酶(PPO)活性均在-10℃低温胁迫时达到峰值,而‘北海道黄杨6号’、北海道黄杨和胶州卫矛叶中各酶活性在-20℃低温胁迫时才达到峰值,它们酶活性峰值出现的时间及高低与其半致死温度的结果相吻合。(5)隶属函数综合评价结果显示,5种卫矛属植物的抗寒能力表现为‘北海道黄杨6号’北海道黄杨胶州卫矛大叶黄杨扶芳藤。研究发现,在低温胁迫条件下,卫矛属植物一方面通过渗透调节物质的合成来提高细胞内的渗透势,另一方面通过增强抗氧化酶活性来清除细胞内过量的活性氧、酚酸类等有害物质,从而对低温环境具有一定的适应能力,这为卫矛属植物抗寒种质的筛选及其在城市绿化中的合理应用提供了理论依据。