Resistance to Adversity of New Poplar Clones

With four poplar clones, namely 84-323 (Populus deltoides cv. ?4-323?, 84-324 (Populus deltoides cv. ?4-324?, 79-35 (Populus ?euramericana cv. ?9-35?, and I-69 (Populus deltoides cv. 慙ux?I-69/55) as a control, researches on cold, drought and salt resistance of the clones were conducted. Electrolyte permeability under a series of low temperatures, relative water loss rate of detached leaves with time series and survival rate and growth performance in salt soil were measured. The results showed that 84-323, 84-324 and 79-35 were resistant to cold as same as I-69 (CK) and more resistant to drought and salinity than I-69 (CK).

Drought tolerance in three hybrid poplar clones submitted to different watering regimes

Aims Poplars grownin North Chinamay experience water-deficient periods in their life cycle.The aim of the present paper was to quantify the response of three clones to different watering regimes and to determine whichcloneamongthe three is the best adapted to drought conditions.Methods Three hybrid poplar clones(clone DN-34,R-247 and OP-367)were used in the present experiment.The seedlings of the three clones were grown under four watering regimes:control(well watered,100%field water capacity(FC))and three drought treatments(drought stress I,50%FC;drought stress II,40%FC;drought stress III,30%FC).Changes in morphological,physical and biochemical indicators of the three hybrid poplar clones were investigated.Important Findings Drought treatment(50%,40%and 30%FC)decreased net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(gs),shoot height,total biomass and chlorophyll(Chl)content in all the three clones and it increased activities of antioxidant enzymes and free proline content.The highest values of the above-mentioned morphological and physiological parameters were recorded in clone OP-367 under 30%FC,followed by clone DN-34 and R-247.Relative leaf water content(RWC)and stem diameter(sd)markedly declined in clone R-247 and DN-34 under drought stress I,II and III,whereas RWC and sd declined in clone OP-367 only under drought stress II and III.Clone OP-367 had more RWC and sd than DN-34 and R-247.Only the 30%FC induced an increase in the root-to-shoot ratio(rs)and water use efficiency(WUE)in all the three clones.OP-367 was the most efficient clone in water absorption and use,for plants of the clone had the highest values of rs and WUE.Our data demonstrate that among the three clones,OP-367 was better able to maintain photosynthesis and growth and lower the damage caused by drought.

Comparison of Quality of Pulping and Paper-Making between Normal Wood and Tension Wood of Poplar Clone 107(Populus×euramericana‘Neva’) Tree

Both of straight and inclining poplar clone 107 tree were selected for studying materials in this paper.The optimal pulping conditions was established by orthogonal experimental design both for normal wood and tension wood,and the quality of pulping and paper-making between normal wood and tension wood was compared with each other. Finally,potential application for improving paper quality of tension wood through increasing beating revolutions was discussed.The result showed that the optimal cooking condition for normal wood was alkali concentration 15%,the highest temperature 164℃,time at highest temperature 75 min,and for tension wood it was alkali concentration 13%,the highest temperature 160℃,time at highest temperature 40 min.Path coefficient of effect of alkali concentration both on pulp yield and kappa value was significant at different levels.By comparison between average result of normal wood and tension wood in quality of pulping and paper-making,it was found that tension wood had higher pulping yield and lower kappa value than normal wood. Furthermore,for all mechanical properties of paper, normal wood hold higher value than tension wood, and even near two times than tension wood,such as burst index and tensile index.However,difference of tear index was quite narrow.Result of one way ANOVA showed that difference of burst index and tear index between normal wood and tension wood was significant at the 0.001 level,of tear index was significant at the 0.05 level.Based on observation of cross surface of paper,it was assumed that contribution of gelatinous layer to rigidity of single fiber had hampered collapse and compression of fiber during paper formation,which is essential for exerting combination between fibers in paper.So, mechanical properties of tension wood paper were decreased accordingly.However,owing to high cellulose content of gelatinous layer,tension wood was easier to pulping than normal wood.Mechanical properties of tension wood paper could be improved by increasing beating revolutions,the final value even close to normal wood paper.But,the increasing effect had a limit.

杨树无性系表型性状及ISSR分子标记遗传多样性分析

【目的】综合表型性状及分子标记多样性分析探明供试的62个杨树无性系的遗传多样性,为杨树进一步遗传改良奠定基础。【方法】选取地径、苗高、叶面积、叶长、叶宽、叶柄长、叶绿素、侧枝数、叶厚、单株总叶片、叶片干质量、叶片含水率等12个表型性状和ISSR分子标记对杨树无性系个体间进行遗传多样性分析,利用PopGen 32、SPSS 16.0及NTsys 2.10e等软件分别计算多样性指数、进行表型性状间的方差分析以及对各无性系进行UPGMA法聚类分析。【结果】侧枝数、单株叶片数、叶片干质量、叶面积以及地径的变异系数均达到了10%以上,叶柄长、叶长、苗高的变异系数也达到了8%以上的水平。利用5条ISSR引物检测到62份杨树无性系多态性谱带百分率平均为89.04%,基因多样度平均为0.4074,Shannon多样性指数(I)平均为0.5304。采用UPGMA法构建的形态和分子标记聚类图将供试材料聚成的类群均有家系内聚为一类的趋势,但也存在较大的差异;表型性状聚类分析主要是根据叶片的相关性状相似度越高的被聚为一个类群;分子标记聚类主要呈现出亲缘关系越近的无性系越容易聚为一个类群的聚类规律。【结论】供试的杨树无性系间表型性状分化程度高,具有丰富的遗传多样性,研究结果为杨树种质资源的改良、种质创新及多元化开发利用提供科学依据。

株行距配置和无性系对杨树人工林碳储量的影响

为探究不同株行距配置和无性系对杨树人工林碳储量的影响,采用林木生物量直接收获法对13年生南林-895杨(NL-895)4种株行距配置(6 m×6 m、4.5 m×8.0 m、5 m×5 m、3 m×8 m)、南林-95杨(NL-95)和南林-797杨(NL-797)6 m×6 m株行距配置林分的碳储量进行了研究。结果表明:不同林分单株生物量存在显著差异(P<0.05),以6 m×6 m株行距配置模式的NL-895单株生物量最高(400.96 kg·株^(-1));4种株行距配置的NL-895林分的生物量不存在显著差异,但在6 m×6 m株行距配置林分中,NL-895和NL-95的生物量显著高于NL-797(P<0.05)。杨树人工林各器官的碳含量(质量分数)在39.79%~47.76%之间,表现为树干>树枝>根系>树叶;不同株行距配置林分的林木碳储量变异趋势与林分生物量相似,6 m×6 m株行距配置NL-895林分的林木碳储量最高,3 m×8 m株行距配置的NL-895林分的林木碳储量最低。不同无性系和株行距配置对杨树人工林土壤(0~100 cm)碳储量有一定影响但不显著,其碳储量约占杨树人工林碳储量的71.7%。同一无性系不同株行距配置林分的总碳储量存在显著差异(P<0.05),而同一株行距配置不同无性系林分总碳储量无显著差异。总体来看,6 m×6 m株行距配置的NL-895林分总碳储量最大(192.46 t·hm^(-2)),分别是4.5 m×8.0 m、5 m×5 m、3 m×8 m株行距配置林分的1.17、1.31、1.38倍。综上所述,在江苏省类似的立地条件下,建议选择NL-895、株行距6 m×6 m的均匀配置作为碳汇林营造的经营模式。

Variation of soil enzyme activity and microbial biomass in poplar plantations of different genotypes and stem spacings

To improve the productivity of poplar planta- tions, a field experiment of split-plot design with four tree spacings and three poplar clones was established, and four soil enzyme activities and microbial biomass were monitored in the trial. Soil enzyme activities, in most cases, were significantly higher in topsoil （0-10 cm） than in lower horizons （10-20 cm）. Soil cellulase, catalase and protease activities during the growing season were higher than during the non-growing season, while invertase activity followed the opposite trend. Soil invertase, cellulase and catalase activities varied by poplar clone but soil protease activity did not. Cellulase and protease activities in the plantation at 5 × 5 m spacing were significantly higher than in the other spacings. The highest catalase activity was recorded at 6 × 6 m spacing. At the same planting density, invertase activity was greater in square spacings than in rectangular spacings. Soil microbial biomass was also significantly affected by seedling spacing and poplar clone. The mean soil MBC was significantly lower in topsoil than in the lower horizon, while MBN showed the opposite pattern. Significantly positive correlations were observed among soil cellulase, protease and catalase activities （p 〈0.01）, whereas soil invertase activity was negatively and significantly correlated with cellulase, protease and catalase activities （p 〈 0.01）. Soil microbial biomass and enzyme activities were not correlated except for a significantly negative correlation between soil MBC and catalase activities. Variations in soil enzyme activity and microbial biomass in different poplar plantations suggest that genotype and planting spacing should be considered when modeling soil nutrient dynamics and managing for long-term site productivity.

小黑杨Rubisco小亚基基因启动子的克隆及表达活性分析

核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco)是光合作用中决定碳同化速率的关键酶,其中小亚基(rbcS)是由核基因编码,并且主要在叶片中表达。利用RT-qPCR技术确定了小黑杨(Populus×xiaohei)叶片中高表达的Rubisco小亚基基因PxrbcS1和PxrbcS2基因,并克隆了其上游2 240、2 174 bp的启动子。对其进行启动子元件分析结果表明,PxrbcS1和PxrbcS2的启动子具有多个与光诱导表达相关的元件,例如G-box、MRE和Box4等元件。构建pBI-121-p PxrbcS1::GUS和pBI-121-p PxrbcS2::GUS植物表达载体并遗传转化84K杨(P. alba×P. glandulosa)。GUS组织化学染色以及qPCR表达分析表明PxrbcS1和PxrbcS2的启动子能够驱动GUS基因在84K杨叶片特异性高表达。总之,上述结果表明该研究成功地从小黑杨中克隆了具有叶片高表达活性的PxrbcS1和PxrbcS2的启动子,该启动子可应用到包括杨树在内的植物光合作用相关的基因功能研究以及提高植物光合作用的遗传操作中。

杨树UGT198基因的生物信息学分析、基因克隆及功能初探

【目的】研究UGT198基因是否参与调控烟草抗虫性,为未来探索其参与调控杨树抗虫性奠定基础。【方法】前期通过分析公共转录组数据发现PtrUGT198基因在杨树响应虫害的转录组中高调表达,对其进行生物信息学及进化分析。以107杨为材料,克隆UGT198基因,构建过量表达载体,利用农杆菌介导法转化烟草获得过量表达转基因株系。通过棉铃虫饲虫试验初步验证UGT198基因是否参与调控抗虫性,分析UGT198基因在调控抗虫性中发挥的功能。【结果】PtrUGT198基因完整的ORF区为1440 bp,编码479个氨基酸,理论分子量为53.14 kDa,等电点为5.92,编码不稳定疏水性蛋白。PtrUGT198蛋白的二级结构α⁃螺旋占41.75%,β⁃折叠占14.61%,β⁃转角占7.10%,无规卷曲占6.53%。PtrUGT198蛋白不存在跨膜区,预测其不属于膜蛋白,为非分泌性蛋白,该蛋白的磷酸化修饰以丝氨酸为主。同源序列对比结果显示PtrUGT198蛋白的C末端存在高度保守的植物次生产物糖基转移酶(Plant secondary product glycosyltransferase,PSPG)基序。系统进化树分析发现,PtrUGT198蛋白与同属植物毛白杨、银白杨和胡杨亲缘关系最近,其次和模式植物烟草有较近的亲缘关系。成功克隆杨树UGT198基因,构建pNC⁃UGT198基因过量表达载体,并转化烟草获得过量表达转基因株系,进行饲虫实验,得到高表达量烟草相对抗虫。【结论】首次成功克隆了UGT198基因,并初步解析其调控抗虫性的功能,为深入了解UGT198基因调控杨树抗虫机理提供参考价值。

Feeding performance of Clostera fulgurita on three clones of Populus deltoides

Poplar leaf defoliator, Clostera fulgurita （Walker） larvae were reared on three Populus deltoides clones （PL1, PL5 and PL7） in the laboratory. The nutritional indices were computed for working out the relationship between food consumption and growth rate of 3rd, 4th and 5th instar larvae on three clones. The result showed that the consumption index （CI）, approximate digestibility （AD）, growth rate （GR）, relative growth rate （RGR） and efficiency of conversion of ingested food （ECI） decreased with the increase in the age of the larvae. Efficiency of conversion of digested food （ECD） increased with increase in age of the larvae. GR and RGR varied significantly, indicating that larval development was enhanced on PL1 as compared to PL5 ＆ PL7. The values of AD, ECI and ECD were not affected by the different clones. Feeding and growth indices could be useful to define a defoliation prediction model.

湘北平原区杨树优良无性系选育及立地适应性评价

针对湘北平原区杨树育种群体及品种资源单一、遗传基础变窄以及适应性减退等问题,定向选育品种与立地相适应的杨树优良无性系,提高杨树遗传改良水平,充分发挥优良无性系增产及土地利用潜力。选择30个杨树无性系在岳阳君山区、益阳沅江市等3个不同立地条件类型进行区域试验,应用多点联合方差分析、AMMI模型和GGE双标图等分析方法,对5~9年生杨树试验林平均胸径、树高、材积、材性等指标以及立地适应性进行综合评价。各参试杨树指标性状无性系间存在极显著差异,胸径、材积性状无性系×地点交互效应显著,树高差异不显著;以综合指标平均材积进行分析,基因型主效应(G)、环境主效应(E)以及基因与环境互作效应(I GE)其平方各占总变异平方和的比例分别为29.5%、59.8%和10.7%;与当前主栽良种比较生长量较高的无性系依次是LA09-N56、LA06-N30、TN02-92、TN02-13、TN01-88、TN01-49、TN01-90、TN01-38和TN01-30。7个杨树无性系木材基本密度、纤维长度、纤维宽度和纤维长宽比范围分别在0.3331~0.3817 g/cm^(3)、1273.09~1366.85μm、19.65~28.19μm和46.05~69.76,均符合纤维材和大径级胶合板材质量要求,其中LA09-N56、LA06-N30两个新无性系不仅速生性能与对照比有大幅提高,且木材基本密度没有下降。综合生长性状的适应性和稳定性考虑,筛选的优良无性系可分为两类,一类是LA06-N30、TN01-90、TN01-38为广泛生境型,在湖洲滩地、江河岸线和内垸林地等不同立地条件下造林均能较充分地发挥自身遗传潜力;另一类是LA09-N56、TN02-92、TN02-13、TN01-88、TN01-49为优良生境型,可选择内垸立地条件较好的地类栽植。

Effects of site conditions on growth and wood properties of Populus×euramericana cv.'74/76'

The growth and wood properties of 240 individual Populus×euramericana cv.’74/76’(hereafter poplar 107)trees planted in Hebei Plain,China was evaluated.Mean annual increments in height,breast height diameter and volume,as well as cellulose,hemicellulose and lignin contents,shrinkage,density,bending strength and modulus of elasticity in the heart wood and sap wood.Environmental factors influencing growth and wood properties were analyzed using correlation and stepwise regres sion.The results show that the coefficients of variation(CVs)of growth traits ranged from 10.6 to 22.4%.The CVs of the chemical properties of heartwood ranged from 4.3 to 30.2%,and for sap wood from 3.2 to 27.5%.The CVs of the physical and mechanical properties of heartwood ranged from 8.6 to 31.7%,and for sapwood from 6.4 to 29.9%.The results of one-way ANOVA showed that there were significant differences in growth traits and wood properties among sites.Soil pH,total and available phosphorus,total potassium,and soil organic matter were key soil factors affecting growth and wood properties of poplar 107,whereas mean annual ground temperatures and precipitation were the main climatic factors.To better cultivate poplar 107,area with less annual rainfall,slightly higher temperature and soil pH value close to neutral should be selected.

白杨无性系叶片水力及经济性状与生物量的关系

【目的】探究杨树无性系叶片水力及经济性状与生物量的关系,以期探寻预测无性系生物量的可靠指标,对早期选育高产速生无性系具有指导意义。【方法】以来源于同一父母本具有不同生长速率的8个4年生白杨无性系为研究对象,在生长季(7—9月)测定叶片水力性状(叶片维管水力导度Kleaves HPFM、叶片水力导度Kleaf EFM、叶脉密度VD、导管直径Dv、导管水力直径Dh、气孔密度SD和气孔长度SL)、叶片经济性状(比叶面积SLA、叶片全碳含量C、全氮含量N和全碳氮比C/N),生长季结束时(10月)计算地上部分生物量AGB,分析无性系间生物量、叶片水力性状和经济性状的差异,探究三者间的关系。【结果】无性系间地上部分生物量、叶片水力性状、经济性状存在显著差异。AGB总体排序为:K1>K2>K3>Z2>Z1>M3>Z3>M1,大部分无性系的生长趋势与母体树(8年生)保持一致。与叶经济性状变异系数(2.0%~12.0%)相比,水力性状变异系数范围较大(4.5%~13.2%)。叶片水力性状和经济性状不相关,但二者均与地上部分生物量相关。在水力性状中,Kleaves HPFM、VD、Dv和Dh越大,AGB越高,均呈显著正相关,而SD、SL和Kleaf EFM与AGB无相关性。在经济性状中,SLA和AGB呈显著负相关,而C、N和C/N与AGB无相关性。多元线性回归分析表明,VD是影响地上部分生物量的主要指标(t=2.957)。【结论】白杨无性系具有稳定的生长趋势,且无性系间叶水力及经济性状存在差异。这为找寻预测生物量指标提供了可能。与经济性状相比,水力性状可以较好地预测该无性系的地上生物量,且叶脉密度(VD)可能是预测地上生物量的关键因子。

川西南二半山区杨树无性系引种育苗初探

为做好川西南二半山区杨树无性系初步选育工作,进一步满足当地造林需求,加快杨树产业发展,分别引进28个杨树无性系,选取布拖县开展苗期试验;以地径和苗高两个主要苗期生长量为指标,初步筛选出适宜在该区域生长的优良无性系。采用方差分析和多重比较分析等方法,结果表明1年生各杨树无性系间苗期生长性状差异较大,以地径和苗高两因素为依据,南林312苗期表现最优,从而为杨树优良无性系在川西南二半山区的推广应用提供参考。

杨树不同无性系耐盐能力评价

【目的】为了研究杨树不同无性系的耐盐程度。【方法】以当年生杨树扦插苗为试验对象,每个无性系数量不少于50株,选择盐碱度为中度以上的盐碱土,取生境土壤测定盐分含量,通过生境调查初步选择出无性系进行盆栽试验,并用不同浓度的盐水浇灌,测得各项生长、生理、生化指标。【结果】根据综合指标值得出辽胡1号杨和小美旱杨为强度耐盐无性系,辽宁杨为中度耐盐无性系,渤丰3号杨和中辽1号杨为轻度耐盐无性系。【结论】杨树不同无性系由于其耐盐方式、耐盐机理、组织结构、细胞生理生化代谢的不同,对杨树耐盐性的研究应该是多项指标的综合评价;用杨树的形态、生长、生理、生化指标建立一套耐盐能力评价体系。

5个杨树无性系抗寒性的测定与评价

采用电导法和原子吸收分光光度法,分别测定了5个杨树无性系一年生休眠苗不同低温处理后的电导率及K+渗出率;对测定结果进行了单因素方差分析与多重比较;建立了各无性系低温(T)-电导率、K+渗出率回归模型,测算出各无性系组织半致死温度在-25℃～-32℃。根据各项指标测定结果对各无性系抗寒性进行了综合评定,结果表明,无性系间抗寒性差异较大,5个无性系抗寒性排序是:57×新>84K>意101杨、新疆杨>毛白杨30号。

杨树无性系根系吸收H_2PO_4^-动力学特征与磷营养效率

在温室条件下 ,应用整株植物长期吸收的营养液培养方法研究杨树无性系根系吸收H2 PO4- 动力学特性及其与磷营养效率的关系 ,以揭示杨树不同无性系间磷营养效率差异的机理。结果表明 ,高效型无性系S1 7、S1 9和 1 0 5根系对H2 PO4- 离子的吸收能力明显强于低效型无性系 1 0 6、797、Ⅰ -69、1 3 88和 3 2 44。与低效型无性系相比 ,S1 7、S1 9和 1 0 5具有较小的米氏常数Km 和吸收临界浓度Cmin,说明它们的根系对H2 PO4- 的亲合力、对低磷浓度的耐受能力较强。在缺磷胁迫条件下 ,S1 7、S1 9和 1 0 5根系系统对H2 PO4- 的亲合能力可增加 2 0 %以上 ,其Km 值分别从 1 3 8、1 3 4和 1 4 0 μmol·L- 1 下降到 1 0 1、1 0 7和 1 1 2 μmol·L- 1 ,而低效型无性系的亲合力则变化很小 ,增加不足 5 %。同样 ,高效型无性系对低磷的耐受能力可增加 85 %以上 ,其Cmin 分别从2 5 5、2 94和 2 68μmol·L- 1 下降到 0 3 0、0 3 5和 0 40 μmol·L- 1 ,但低效型无性系的增加均不足 1 5 %。杨树无性系在根系吸收H2 PO4- 动力学特性方面的不同是其磷营养效率差异的重要原因之一。最大吸收速率Vmax,作为根系吸收动力学参数之一 ,对阐明杨树无性系磷营养效率的作用尚不够确定。

几种光合作用光响应典型模型的比较研究

光响应曲线是判定植物光合效率的重要方法,通过曲线可以获得植物光合特性的相关生理参数,但不同模型提取的光响应参数和指标存在差异。本文选择直角双曲线、非直角双曲线和两种指数曲线模型,分别对3个品系常绿杨光响应数据进行拟合,提取了各光响应曲线模型的主要特征参数,对比分析了各模型参数间的差异,并对光饱和点(LSP)的不同计算方法进行了讨论。最后用巨尾桉光响应数据对分析结果作了进一步验证。结果表明,直角和非直角双曲线模型拟合的最大净光合速率(P’max)、表观量子效率(a)及暗呼吸速率(Rd)值高于指数模型拟合值,且直角双曲线拟合的各参数均比非直角双曲线拟合的各参数的值大,而两指数模型各参数拟合值基本一致;在LSP计算方法中,用光通量200μmo.lm-2.s-1以下的点拟合的Pn-I直线与其它模型相结合得到光饱和点的方法不可靠,会使计算结果明显偏小,用接近最大总光合速率Pmax一定比例的方法估计LSP也存在较大偏差,而P’max由于消除了Rd的影响,计算光饱和点时各模型的估计比例相对固定,是一个比较理想的LSP估计方法,初步得出直角、非直角及指数模型用P’max来估计光饱和点时应选取的比例分别为(78±1)%、(82±1)%及(96±1)%。

杨树无性系生长和材性的遗传变异及多性状选择

以７年生２５个杨树无性系为材料研究了生长和材质性状的遗传变异及性状之间的相关．６个性状纤维长、纤维宽、长宽比、木材密度、树高、胸径在无性系间均存在极显著的差异。生长和材质性状受中等更强度的遗传控制．６个性状的重复力分别为８１．９％，７３．３％，７０．５２％。６４．３％．６８．８％，７０．５４％．胸径和树高之间、纤维长度与纤维长宽比、胸径之间、木材密度与胸径之间都呈现出较高的遗传正相关．宜接选择效果优于间接选择，指数选择优于直接选择。由４性状树高、胸径、纤维长度与基本密度配合的选择指数对本实验群体比较合适。利用选择指数评选出４个生长和材质兼优的优良无性系。

盐胁迫下白杨无性系苗木体内离子分配及比较

以白杨杂种无性系及其亲本当年生苗木为材料 ,分析了盐胁迫下无性系的离子含量 ,及 Na+ 、K+ 、Ca+ +在植物体内运输和分配特点 ,并对无性系间差异进行了比较。研究表明 ,随盐浓度提高 ,植物体内Na+ 含量迅速提高 ,K+ 、Ca+ + 含量降低 ;盐分胁迫下 ,根部 Na+ 含量较高 ,叶片 Na+ 中含量最低 ,K+ 、Ca+ +含量则相反 ,特别是 Ca+ + ,其分布顺序为叶 >茎 >根。杂种无性系 B430及其亲本新疆杨对 K+ 和 Ca+ + 运输的选择性比毛白杨高 ,而对 Na+ 运输的选择性则比毛白杨低 ,从而导致根部存留的 Na+ 较多 ,叶片分配的 Na+ 数量较少 ,从而减轻 Na+ 对叶片的伤害。综合分析表明 B430和新疆杨耐盐能力最强 ,毛新杨其次 ,毛白杨最差。

低温胁迫下美洲黑杨与大青杨杂种无性系若干生理指标变化研究

以美洲黑杨与大青杨6个杂种无性系1年生扦插苗为材料,对其5℃连续5d低温胁迫过程中若干生理指标的变化规律进行研究。结果表明,随着胁迫时间的延长,6个无性系叶绿素含量和最大光能转换效率逐渐降低,丙二醛含量保持逐渐上升趋势,而可溶性糖与可溶性蛋白含量均呈现出先上升后下降的趋势。此外,各指标6个无性系间差异明显:无性系DU146和DU147叶绿素含量、最大光能转换效率、可溶性糖以及可溶性蛋白含量在胁迫过程中均相对较高,而丙二醛含量及其增加倍数相对较低,说明其具有较强的光合作用及低温耐受能力;其次是无性系DU136和DU165;而无性系DU135和DU150光合作用及低温耐受能力较弱。