Photosynthetic Characteristic Variation of Different Provenances of Liriodendron chinense Sarg. at Seedling Stage

[Objective]The aim was to study photosynthetic characteristic variation of different provenances of Liriodendron chinense Sarg. at seedling stage and provide the theoretical basis for work of provenance selection,parent selection of hybridizing breeding,genetic resource conservation of L.chinense Sarg.. [Method]With 13 provenances 1-year-old L.chinense Sarg. seedlings as tested materials,the photosynthetic characteristic variation of different provenances were studied. [Result]The L.chinense Sarg. seedlings of different provenances had the significant difference on net photosynthetic rate （Pn）,stomata conductivity （Gs） and water use efficiency （WUE）. The Pn of the highest provenance was 2.36 times the lowest. Majority seed sources light saturation point （LSP） were in 800-1 200 μmol photons/（m2·s）. Gs,transpiration rate （Tr） and Pn were significantly positively correlated,and the three had a significant positive correlation with the light compensation point （LCP）. Pn,LSP and WUE were negatively correlated. [Conclusion]The photosynthetic characteristics of L.chinense Sarg. had significant variation among provenances. Maybe Gs is the important factor leading to difference in Pn of L.chinense Sarg. seedlings. L.chinense Sarg. seedlings still need higher light intensity and more water.

Optimization on Ultrasonic Extraction Method of Total Flavonoids for Liriodendron chinense Sarg.×L.tulipifera L. by Response Surface Methodology (RSM)

With the leaves,bark and roots of Liriodendron chinense Sarg.× L.tulipifera L.as experiment materials,the ultrasonic-assisted extraction conditions of total flavonoids were optimized by response surface Box-Behnken test design.Ultrasonic time and liquid-to-solid ratio had significant effects on the extraction amount of flavonoids from the leaves of L.chinense Sarg.× L.tulipifera L.;ultrasonic temperature and liquid-to-solid ratio had an interaction on the extraction amount of flavonoids;and the optimum ultrasonic time,temperature and liquid-to-solid ratio for the extraction of flavonoids from leaves of L.chinense Sarg.× L.tulipifera L.were 19.82 min,28.60 ℃ and 9.48 ml/g,respectively.Ultrasonic time,temperature and liquid-to-solid ratio had significant effects on the extraction amount of flavonoids from L.chinense Sarg.× L.tulipifera L.;there was a significant interaction between any two of the factors,which had a significant effect on the extraction of flavonoids;and the optimum extraction parameters for flavonoids in the bark were the ultrasonic time of 33.66 min,the ultrasonic temperature at 32.85 ℃ and the liquid-to-solid ratio of 11.39 ml/g.Ultrasonic time and liquid-to-solid ratio had significant effects on the extraction of flavonoids from roots;there was a significant interaction between ultrasonic time and liquid-to-solid ratio and between ultrasonic temperature and liquid-to-solid ratio;and the optimum extraction parameters for flavonoids from the roots of L.chinense Sarg.× L.tulipifera L.were the ultrasonic time of 32.38 min,the ultrasonic temperature at 25.0 ℃ and the liquid-to-solid ratio of 8.00 ml/g.The results of the three models were stable.The models are feasible and have good application value.

Identification and Transcriptional Regulation of CAMTA Genes in Liriodendron chinense

This study explores CAMTA genes in the rare and endangered Chinese plant species,Liriodendron chinense.Despite the completion of whole-genome sequencing,the roles of CAMTA genes in calcium regulation and stress responses in this species remain largely unexplored.Within the L.chinense genome,we identified two CAMTA genes,Lchi09764 and Lchi222536,characterized by four functional domains:CG-1,TIG,ANK repeats,and IQ motifs.Our analyses,including phylogenetic investigations,cis-regulatory element analyses,and chromosomal location studies,aim to elucidate the defining features of CAMTA genes in L.chinense.Applying Weighted Gene Co-Expression Network Analysis(WGCNA),we explored the impact of CAMTA genes on different organs and their regulation under abiotic stress conditions.The identification of significant gene modules and the prediction of promoter binding sites revealed co-expressed genes associated with CAMTA transcription factors.In summary,this study provides initial insights into CAMTA genes in L.chinense,laying the groundwork for future research on their evolution and biological roles.This knowledge enhancement contributes to a better understanding of plant responses to environmental stress—an essential aspect of plant biology.

庐山鹅掌楸(Liriodendron chinense)幼苗蒸腾特性研究

庐山山地上的鹅掌揪幼苗，在夏季晴天土壤供水充足的条件下，其叶片蒸腾速率的日变化为午后高峰型，日蒸腾量为70．92molH2Om-2d-1，最大蒸腾速率达3.9mmolH2Om-21s-1,叶／气温度差、气孔导度、相对湿度等因素对蒸腾速率的影响最显著；鹅掌揪幼苗的水分利用率日平均为4．142mmolCO2mol-1H2o，最高可达11.8mmolCO2mo1-1H2O。

Effects of Drought Stress on Contents of Endogenous Hormones in Leaves of Different Clones of Liriodendron chinense×L. tulipifera

[Objective] The aim was to study the effects of drought stress on contents of endogenous hormones in leaves of different clones of Liriodendron chinense×L. tulipifera. Drought-resistant Liriodendron chinense×L. tulipifera clones NE25,NE78 and drought-sensitive Liriodendron chinense×L. tulipifera clones NE04,NE23 were selected as experimental materials to study the content changes of four kinds of endogenous hormones such as abscisic acid （ABA）,indoleacetic acid （IAA）,ribosylzeatin （ZR） and jasmonic acid （JA） in leaves of different clones under drought stress. [Result] Under drought stress,ABA was accumulated I leaves of different clones,however,the content changes in drought-resistant clones were not obvious; IAA content showed a decreasing trend,and the content changes n drought-resistant clones during later period of drought stress was decreased; JA content showed an increasing trend in leaves of drought-sensitive clones,indicating that drought-sensitive clones had to maintain higher contents of JA to resist drought stress. [Conclusion] The result of this study had provided scientific basis for the screening,planting and application of drougt-resistant clones of Liriodendron chinense×L. tulipifera.

鹅掌楸（Liriodendron chinense）遗传多样性的等位酶论证

选择５个具有地理代表性的鹅掌楸（Ｌｉｒｉｏｄｅｎｄｒｏｎｃｈｉｎｅｎｓｅ（Ｈｅｍｓｌ．）Ｓａｒｇ．）种群，分析６种酶系统９个位点上２７个等位基因的遗传变异。结果表明，鹅掌楸种内保存较高的等位酶变异。遗传多样性的分布特点与种群地理分布型式一致，鹅掌楸的种内分化主要表现为东、西部种群之间的差异，东部亚区的总的基因丰富程度低于西部亚区。同时，东部亚区内“岛”状隔离分布使其中的种群分化加深，种群间差异大于西部亚区中呈“带”状地理连续分布的种群间的分化。

Genome-wide identification and cold stress-induced expression analysis of the CBF gene family in Liriodendron chinense

Cold-resistance pathways that operate in model plants such as Arabidopsis thaliana and Oryza sativa have been studied extensively.It has been found that CBF genes play an important role in plant cold resistance.Liriodendron chinense,a tree known for its graceful tree shape and widely spread in south China,has weak cold tolerance.However,little is known about its response to cold.To further study the function of L.chinense CBF gene family,we started by characterizing all members of this gene family in the L.chinense genome and their expression profiling.Phylogenetic analysis found that 14 CBF genes in L.chinense are more closely related to their homologues in woody plants and A.thaliana than those in O.sativa.Cis-acting elements and GO analysis showed that some LcCBF genes participated in the biological process of cold stress response.The transcriptomic and RT-qPCR data showed that most of LcCBF genes displayed an initially increasing and subsequently decreasing trend during cold stress course and the expression profile of each member was different.Some LcCBF genes exhibited a different abundance in callus,root,stem and leaf tissues.The structure and expression characteristics of LcCBF genes imply that they may have similar and different functions in response to cold stress conditions.The identification and analysis of LcCBF gene family have laid the foundation for future studies into L.chinense cold stress mechanisms and for the cultivation of cold-resistance cultivars.

Changes in soil organic carbon and aggregate stability following a chronosequence of Liriodendron chinense plantations

The objectives for this study were to determine changes in soil organic carbon(SOC)components and water-stable aggregates for soil profi les from diff erent ages of plantations of Liriodendron chinense and to clarify which organic carbon component is more closely associated with the formation and stability of soil aggregates.Three layers of soil(depths 0–20 cm,20–40 cm,40–60 cm)were collected from young,half-mature and mature stages of L.chinense.SOC,readily oxidizable organic carbon,chemically stable organic carbon and aggregate composition were determined.Intermediate stable organic carbon,the microbial quotient and aggregate stability(mean weight diameter)were calculated.SOC and aggregate stability in the L.chinense plantation did not increase linearly with an increase in L.chinense age;rather,they fi rst decreased,then increased with increasing age of L.chinense.The microbial quotient had a negative eff ect on the level of organic carbon and the stability of aggregates,while chemically stable organic carbon had a positive eff ect,which explained 55.0%and 19.3%of the total variation,respectively(P<0.01).Therefore,more attention should be paid of these two indicators in the future.

Nutrient element contents of cutting seedlings of hybrid species (Liriodendron chinense x tulipifera)

The cutting seedlings of Liriodendron chinense x tulipifera were treated with the different concentrations of auxin (treatment1: IBA of 50 gkg-1 + NAA of 300 gkg-1; treatment2: IBA of 100 gkg-1 + NAA of 300 gkg-1). The biomass and the nutrient element contents for different organs (root, stem, leaf) of cutting seedling of Liriodendron chinense x tulipifera were measured by the dry method, Kjeldahl method and Atomic Absorption Spectroscopy method. The result showed that the biomass of root, stem, and leaf of the cutting seedling treated with auxin was all remarkably increased. The contents of element C in root, stem and leaf had no significant difference between the control and auxin treatments, while the contents of N, P, K and Ca in stem were much lower than that in leaf and root. Variance analysis showed that for the same organ with different concentration treatment of auxin, the four nutrient elements (N, P, K, and Ca) had no significant difference in contents, while there existed significant or very significant difference in contents of the four nutrient elements in different organs with the same concentration auxin treatment. The N, P, K and Ca contents were very low in cutting seedlings; as a result, additional fertilizer should be applied to the seedlings when they were planted in the field.

Research on the Effects of Light Intensity and Seeding Density on the Seed Germination and Seedling Growth of Liriodendron chinense

It provides a theoretical basis for the artificial promotion of the reproduction and regeneration of Liriodendron chinense through exploring the effects of light intensity and seeding density on the seed germination and seedling growth of this rare plant. Controlled experiments were conducted by setting different seeding densities and shading intensities to observe and detect the seed germination and seedling growth under different experimental conditions. The data were analyzed by SPSS and the model was fitted to calculate the seed germination rate, seedling emergence rate and seedling growth parameters of Liriodendron chinense, which were used to analyze the effects of seeding density and light intensity on the seed germination and seedling growth of Liriodendron chinense. Light has a significant impact on the seed germination and seedling growth of Liriodendron chinense (P P > 0.05). High density promotes the seedling height (the seedling height showed a rising trend with the increase of seeding density, reaching the highest at 500 seeds/m2. “3-stitch + 300 seeds/m2” combination is an appropriate condition for Liriodendron chinense reproduction since it can realize higher germination rate and better seedling growth potential. The seedling height and basal diameter growth curve of Liriodendron chinense fits well to the Logistic equation (R2 ≥ 0.977). Light has a significant impact on the seed germination and seedling growth of Liriodendron chinense, and appropriate shading treatment can increase the seed germination rate and seedling emergence rate of Liriodendron chinense. Seeding density has little influence on the seed germination rate of Liriodendron chinense, but high density will promote seedling height.

Growth Situation of Liriodendron chinense Seedlings and Soil Fertility in Northern Guangxi Province

[Objective] This study aimed to study the seedling nursery and afforesta- tion of Liriodendron chinense （Hemsl.）.Sarg. in northern Guangxi Province, thereby providing theoretical basis for the extension of L. chinense in this region. [Method] The growth situation of L. chinense seedlings and soil fertility in northern Guangxi Province were investigated. [Result] The L. chinense seedlings in northern Guangxi Province showed significant changes during the growth period. Among the three- year-old L. chinense plants, the average plant height reached as high as 331.11 cm, the average ground diameter was 5.05 cm, and the average crown diameter was 122.22 cm. After three years＇ afforestation with one-year-old seedlings, the av- erage plant height of L. chinense was 357.20 cm, the average ground diameter was 6.53 cm, and the average crown diameter was 170.43 cm. The detection results of soil fertility were as follows： the soil was strongly acidic; the organic matter and to- tal phosphorus contents were moderate; and the total potassium content was rela- tively abundant. [Conclusion] L. chinense grows rapidly in northern Guangxi Province of China, and is suitable for extension in this area.

鹅掌楸基因组部分SNP标记在种源评价中的应用

以6个鹅掌楸(Liriodendron chinense)种源和3个北美鹅掌楸(Liriodendron tulipifera)种源共计23个个体作为研究群体,选取11对真实SNP位点,对这253个SNP标记的PCR产物进行正反向Sanger测序。结果表明:在11个真实SNP位点中,8个SNP位点在中国鹅掌楸和北美鹅掌楸间呈现出多态性,其中3个位点是检测鹅掌楸和北美鹅掌楸种间分化的潜在标记。11个SNP标记在北美鹅掌楸种内都没有多态性。lm_ll_10205、lm_ll_10836、lm_ll_3853和lm_ll_82464个SNP位点在我国东部的湖南浏阳、浙江松阳和江西庐山3个种源间存在多态性,仅有lm_ll_10205位点在我国西部种源间存在多态性。前期开发的SNP标记可以用于鹅掌楸种源遗传多样性的研究。研究种源间SNP位点的变异特征为揭示鹅掌楸的起源、进化以及遗传变异多样性提供了科学数据。

湘西石漠化区湿地松-马褂木人工混交林林分结构及土壤理化性质研究

为探究湘西石漠化区湿地松-马褂木人工混交林林分结构及土壤理化性质,该研究以湘西石漠化地区湿地松-马褂木人工针阔混交林为对象,利用植物群落学分析和野外取样检测的方法,分析林分结构和土壤理化性质,运用Winklemass 1.0计算林分空间结构参数,并用三维离散随机变量分析了优势种的空间分布格局。结果表明:(1)林分内胸径(DBH)≥2 cm的林木株数为897 plants·hm^(-2),隶属于15科16属。主林层为湿地松,平均DBH为32.3 cm,重要值为44.2%;次林层为阔叶树,中幼龄林木居多,其中樟树、马褂木为优势树种,重要值分别为17.1%和13.2%。此外,还存在较多处于劣势生态位的天然更新种。(2)林木的水平分布格局偏向于随机分布(W=0.503);林分整体趋向于中庸偏劣势过渡的态势(U=0.505);种间隔离程度较高(M=0.689),林木混交状况良好。空间结构参数的三维离散随机变量表明,湿地松87.3%为优势和亚优势,马褂木41.7%为亚优势、26.9%为中庸态势,樟树23.5%为中庸态势、56.8%为劣势和绝对劣势。(3)林分土壤pH值趋于中性;与撂荒地相比,林分土壤的容重、持水量、孔隙度、有机碳、全钾、全氮、全磷等因子均明显改善,但整体而言,林分土壤仍然较为贫瘠,局部土壤紧实,保水能力差。综上表明,湿地松、马褂木作为先锋树种生长43年后,林分有向异龄林、强度混交林演替的趋势;林分内中幼龄阔叶树株数占比较大,近熟林出现断层,老龄针叶树占据优势生态区位,需抽针补阔、间针育阔,择伐劣势木,促使林分向阳生性阔叶树为主、中生性和耐阴性阔叶树为次的林分结构演替。该研究结果为湘西石漠化区的植被恢复、人工林结构优化和土壤改良提供了理论依据。

36年生鹅掌楸与檫木混交造林效果及林分结构

以龙山县中海拔山区的36年生鹅掌楸与檫木混交林为研究对象,对混交林的混交效果、萌蘖对鹅掌楸生长的影响及鹅掌楸林分结构等进行了研究.结果表明:鹅掌楸与檫木不适宜营建混交林,36年生鹅掌楸混交林林分生长量中等,现有密度756±80株/hm 2,可作大中径材培育;萌蘖对鹅掌楸的直径、冠幅和蓄积有显著影响,鹅掌楸幼树需及时除蘖整枝;优势树种鹅掌楸直径分布呈左偏的近似正态分布,其模型适用性χ2检验结果仅遵从正态分布,不遵从Weibull分布;鹅掌楸树高分布呈右偏的近似正态分布,其模型适用性未通过χ2检验,不遵从正态分布,也不遵从Weibull分布;三次方程为鹅掌楸树高-直径最优拟合曲线方程.

龙山县中海拔山区鹅掌楸人工林单木生长规律与模型研究

以龙山县砂子坡国有林场36年生鹅掌楸人工林为研究对象,采用样地调查分析法、平均解析木法等方法分析了鹅掌楸人工林的胸径、树高和材积生长特征,并对胸径、树高和材积的生长过程进行了拟合,结果表明:(1)36年生鹅掌楸胸径总生长量和树高总生长量均持续平缓增长,第36年时分别达到20.1cm和20.7m;材积总生长量前期增长较慢,第24年后快速增长,第36年达到0.32745m^(3)。(2)胸径和树高的连年生长量上下波动较大;胸径平均生长量前15a快速增长,后期保持在0.54cm左右;树高平均生长量持续下降,第36年降至0.57m;材积连年生长量和平均生长量均持续增长,第36年分别达0.02136m^(3)和0.00850m^(3);36年生鹅掌楸未达到数量成熟,还不能确定主伐年龄;建议在第14~15年进行一次透光伐、第28~30年进行一次生长疏伐为宜。(3)通过分析得出胸径、树高和材积最优生长模型分别为Korf方程、Roляcp方程和Logistic方程;筛选出的各生长模型可用于预测龙山县中海拔山区鹅掌楸人工林幼龄林、中龄林和近熟林的生长情况,指导鹅掌楸人工林的经营与管理。

鹅掌楸天然林优势树种生态位与种间联结性

以鄂西南地区珍稀植物鹅掌楸天然林群落为研究对象,探究鄂西南地区鹅掌楸天然林群落主要优势树种的生态位与种间联结性特征,基于样地调查数据,采用生态位宽度、生态位重叠、χ~2检验、Pearson相关系数与Spearman秩相关系数分析等方法,对群落中重要值排名前20的优势树种生态位与种间关系特征进行分析。结果显示:群落中鹅掌楸重要值最大,为14.38%,Shannon-Weaver生态位宽度与Levins生态位宽度也最大,分别为3.48和4.56,各物种重要值与生态位排序并不相同,群落整体Pianka生态位重叠指数平均值为0.288,鹅掌楸与其他优势树种的生态位重叠指数平均值为0.413,说明该群落中鹅掌楸种群资源利用程度与宽度均较强,具有较高的竞争优势,且群落目前处于结构不稳定阶段,存在充足的资源环境,生物多样性发展潜力较大。群落总体联结性表现为不显著负联结,大部分物种之间独立性较强。各种对中相关性达到显著以上的极少,大多数种对之间联结性较弱,正负关联比均小于1,说明该群落目前可能存在较为频繁的物种更迭,且鹅掌楸种群与其它种群联结性均呈不显著或相互独立状态,在不考虑人为干扰与种群生殖特性的情况下,鹅掌楸具有较强的生存能力。综合来看,鹅掌楸天然林群落各物种之间竞争并不激烈,种间关联性较弱,群落目前处于演替中期,结构变化明显,野生鹅掌楸种群生存良好。

杉木与鹅掌楸混交造林效果初步研究

为了解杉木与鹅掌楸混交效果,开展了杉木与鹅掌楸1∶1比例株间混交和7∶3比例插花混交试验,同时营造杉木纯林进行了对比。12 a生的试验林调查分析结果表明:杉木-鹅掌楸混交林与杉木纯林相比,杉木的树高、胸径均有不同程度的提高,杉木与鹅掌楸7∶3比例插花混交林中杉木的树高、胸径与杉木纯林之间均有显著差异,杉木与鹅掌楸1∶1比例株间混交林中杉木的树高、胸径与杉木纯林之间的差异不显著。杉木-鹅掌楸混交林土壤与杉木纯林土壤相比,土壤通透性增强,土壤中营养物质含量增加。杉木与鹅掌楸按7∶3比例插花混交比较合适。

鄂西南鹅掌楸天然林林分结构特征

以鄂西南鹤峰县鹅掌楸天然林为研究对象,通过对林分空间结构(角尺度、大小比、混交度)和林分非空间结构(径级结构、树高结构、重要值)的研究与分析,直观地反映其林分结构的特征,查清该区鹅掌楸种群的发展现状,为鹅掌楸天然林的合理保护与科学经营提供依据。在鹅掌楸天然林集中生长的代表性地段建立17个20 m×20 m调查样地,进行每木定位与检尺调查,应用Excel 2019、Winkelmass 2.0软件对样地调查数据进行处理与分析。结果表明:研究区鹅掌楸天然林中共73个树种,鹅掌楸为该群落的优势种,生长处优势地位(U=0.17),种群整体呈轻微聚集分布(W为0.56),同时该种群在林分中呈现极强度混交状态(M=0.85);种群整体径级、树高分布都呈右偏正态分布,小径级林木株数很少,种群整体呈现稳定型→衰退型。FSSI均值为0.82,FSSD均值为0.30,林分空间结构为接近于理想状态(41.18%)或达到理想状态(58.82%)。鹅掌楸天然林处于演替后期,林分结构整体上较为理想,可对处于聚集分布的林木进行适当调整,辅以一定人为促进更新的措施,促使鹅掌楸林分结构更加合理。

马褂木人工林工艺成熟龄的确定

林业生产实践中经常需要计算林分的工艺成熟龄。为解决生产中一个马褂木林分工艺成熟龄的计算实例,进而对林分工艺成熟龄的计算进行了研究和探讨。理论上林分工艺成熟龄的计算方法有生长过程表结合材种出材量表法、标准地法和马尔丁法等几种。经过对比分析,认为生产中常需计算工艺成熟龄的小面积人工同龄纯林比较适宜采用马尔丁法。用此法对洪江市某处的马褂木人工林分作造纸材时的工艺成熟龄进行了计算,得出了该林分工艺成熟龄为10年。使用马尔丁法时,关键是选择好目的材种;计算参数可结合市场需求适当调整;解析木的选取以线形随机选择为好,数量30株左右即可。

利用RAPD标记分析北美鹅掌楸与鹅掌楸种间遗传多样性

利用RAPD标记技术对鹅掌楸属 (LiriodendronL .) 2个现存种鹅掌楸〔Liriodendronchinense (Hemsl.)Sarg.〕和北美鹅掌楸 (LiriodendrontulipiferaLinn .)的遗传多样性进行分析 ,结果表明 :2个种都有较高的遗传多样性 ,但北美鹅掌楸的遗传多样性水平高于鹅掌楸 ;鹅掌楸的遗传变异主要来自地理种源内 ,而北美鹅掌楸的遗传变异主要来自地理种源间 ;与美国密苏里和路易斯安娜的北美鹅掌楸相比 ,鹅掌楸的遗传距离更接近于南卡罗来那。