Diurnal and seasonal dynamics of soil respiration in a Platycladus orientalis forest stand on the semiarid Loess Plateau, China

Forest ecosystems on China's Loess Plateau are receiving increasing attention because of their special importance in carbon fixation and conservation of soil and water in the region.Soil respiration was investigated in Platycladus orientalis forest stands of the region at diurnal and seasonal scales.The daily and seasonal average values of soil respiration were 2.53μmol·m^(-2)·s^(-1)and 3.78μmol·m^(-2)·s^(-1),respectively.On a diurnal and seasonal scale,the variations of soil respiration in the P.orientalis forest show a one-peak pattern.The diurnal dynamics of soil respiration were mainly driven by soil temperature.However,the relationship between soil respiration and soil temperature was not significant,mainly because of the hysteresis effect of soil respiration on soil temperature.Soil moisture plays another dominant role in the ecosystem carbon balance,but was not affected by soil temperature in P.orientalis forest on the semiarid Loess Plateau.

The Mechanism of Pollination in Platycladus orientalis and Thuja occidentalis (Cupressaceae)

The pollination mechanisms of Platycladus orientalis (L.) Franco and Thuja occidentalis L. seem to be of the same type, as based on the morphological study of the change in pollination drop, during the process of pollination. Entering the pollination drop, the pollen may alter the surface of the drop or reduce the secretion of the ovule with concomitant increase of evaporation. It has been further noticed that the dynamiechange of the drop withdrawal rate was closely associated with the different kinds of pollen received. It seemsthat the withdrawal of the pollination drop may be induced by pollen from plants consanguineous to P. orientalis, almost as effective as from pollen of P. orientalis itself and comparatively more effective than the foreignpollen received from distant plant species. The drop withdrawal could he mainly induced by the pollen that causes the reduction of ovule secretion.

Annual growth of Fagus orientalis is limited by spring drought conditions in Iran’s Golestan Province

Due to the lack of a uniform and accurate defi-nition of‘drought’,several indicators have been introduced based on different variables and methods,and the efficiency of each of these is determined according to their relationship with drought.The relationship between two drought indices,SPI(standardized precipitation index)and SPEI(standard-ized precipitation-evapotranspiration index)in different sea-sons was investigated using annual rings of 15 tree samples to determine the effect of drought on the growth of oriental beech(Fagus orientalis Lipsky)in the Hyrcanian forests of northern Iran.The different evapotranspiration calcula-tion methods were evaluated on SPEI efficiency based on Hargreaves-Samani,Thornthwaite,and Penman-Monteith methods using the step-by-step M5 decision tree regression method.The results show that SPEI based on the Penman-Monteith in a three-month time scale(spring)had similar temporal changes and a better relationship with annual tree rings(R^(2)=0.81)at a 0.05 significant level.Abrupt change and a decreasing trend in the time series of annual tree rings are similar to the variation in the SPEI based on the Penman-Monteith method.Factors affecting evapotranspiration,temperature,wind speed,and sunshine hours(used in the Penman-Monteith method),increased but precipitation decreased.Using non-linear modeling methods,SPEI based on Penman-Monteith best illustrated climate changes affecting tree growth.

Over-mature beech trees (Fagus orientalis Lipsky) and close-to-nature forestry in northern Iran

Oriental Beech is the most important commercial tree species in northern Iran. In recent years wood production companies interested in felling large beech trees for profit have challenged advocates of close-to-nature silviculture who favor conservation. Our study objective was to assess the economic value of over-mature beech trees by relating tree diameter （DBH） to amount of decay. Based on the location of onset of decay, we categorized three types of decay as stump, stem, and crown decay. Trees of greater diameter （age） typically showed greater decay in the stem. Percent of decayed volume, diameter of decayed tissue, and length of decay in tree stems varied between 0.5%-64.3%, 15 cm-75 cm, and 2.0-19.5 m, respectively. With increasing trunk diameter, the propor- tion of truck decay increased. Red heart and dark red heart constituted 25% and 14.3% of sampled trees, respectively. However, we found no correlation between intensity of stem decay and morphological charac- teristics of trees. Seedlings were not abundant around the bases of over-mature trees, suggesting that the trees did not contribute to regeneration of the stand. Beech trees of diameter 〉1 m do not provide valu- able round wood for industries and cause to raise wood production costs. We recommend that these trees 〉1 m DBH should be retained in forest stands because of their low commercial value but high ecological and conservational values such as maintaining biodiversity in forest ecosystems.

Volatile Oil of Platycladus Orientalis(L.)Franco Leaves Exerts Strong Anti-inflammatory Effects via Inhibiting the IκB/NF-κB Pathway

This study was designed to investigate the anti-inflammatory effects of volatile oil of Platycladus orientalis(L.)Franco leaves(VOPF)and the underlying molecular mechanisms by using the non-infectious inflammation rat models and infectious inflammation mouse models.Ear swelling and intraperitoneal capillary permeability in mice,and carrageenan-induced toe swelling and cotton ball-induced granuloma in rats were used to reveal anti-inflammatory effects of VOPF.Moreover,the lipopolysaccharide(LPS)-induced mouse model of acute lung injury was used to explore the anti-inflammatory mechanism of VOPF.The results showed that VOPF could significantly inhibit auricular swelling,intraperitoneal capillary permeability in mice,and reduce granuloma swelling and paw swelling in rats.Furthermore,it significantly alleviated the pathological damage of the lung tissue.In addition,VOPF could reduce the contents of IL-1β and TNF-αand increase the content of IL-10 in the serum.It had little effect on the expression of p65 but reduced the phosphorylation level of p65 and IκB in NF-κB pathway.In conclusion,VOPF has anti-inflammatory effects and the mechanisms involve the down-regulation of the phosphorylation levels of p65 and IκB and blockage of the NF-κB signaling pathway.

Evapotranspiration estimation of Platycladus orientalis in Northern China based on various models

Platycladus orientalis is one of the most popular afforestation species and greening species for water management in arid and semi-arid regions of northern China. We applied various models to estimate and validate artificial P. orientalis forest evapotranspiration features with the goal of accurately estimating the water use of a P.orientalis plantation. The American Society of Civil Engineers Evapotranspiration–Penman–Monteith model（APM） and FAO56–Penman–Monteith model（FPM） are extensively applied for vegetation evapotranspiration estimation because their reliability has been validated by many scholars. The Priestley–Taylor model（PT） and Hargreaves model（HS） require only the daily maximum temperature,daily minimum temperature and solar radiation to estimate evapotranspiration and are thus widely applied to grasslands but not to forests. We used the Energy Balance Bowen Ratio（EBBR） system to validate the accuracy of the four models. The results indicated that：（1） Compared to the EBBR measurement annual value, APM was the most accurate, followed by FPM, and PT;（2） During the year, the accuracies of the four models varied. APM and FPM underestimated evapotranspiration during June, July and August, whereas PT and HS overestimated evapotranspiration during this period. In the rest of the year, the estimation accuracies were reversed;（3） An analysis of the possible reasons indicated that wind speed, air temperature and precipitation were the most important contributors.High temperatures were measured in June, July and August, which led to an overestimation by PT and HS because these two models only calculated the temperature and radiation without vegetation information. Underestimation also occurred when a low temperature was recorded. Though APM and FPM addressed both meteorological and vegetation factors, slight deviations still existed; and（4） The two models were modified based on EBBR-measured data. Relative humidity was introduced into PT, and parameter ‘‘A’’ in the HS estimation model was amended to1.41. The accuracy of the modified models significantly increased. The study highlighted the application, comparison and improvement of four models in estimating evapotranspiration and offers more approaches to assess forest hydrological functions.

Study on the Practical Mature Age of Individual Platycladus orientalis

This study was conducted on the analytic tree and got the fitting empirical equation of tree growth, in which the tree growth rate was used as the variable and time as the independent variable. The arithmetical operation to the function got the mature age of tree growth, and the mature ages of the timer forest, the protection forest and the special-purpose forest of Platycladus orientalis were 71, 111 and 141 a, respectively. In addition, the application as well as the research direction and matters needing attention were proposed.

Advances in Research of Chemical Components and Pharmacological Effects of Platycladus orientalis Leaves

Platycladi Cacumen(Platycladus orientalis leaf)is a traditional Chinese medicine with a variety of medicinal values,and its efficacy has been recorded by many ancient books.Its chemical components mainly include flavonoids,volatile oil,tannins and so on.Pharmacological studies have confirmed that P.orientalis leaves have various pharmacological effects such as antibacterial,anti-oxidant,anti-tumor,hair growth promoting and hemostatic effects.Through review of the research on the chemical components and pharmacological effects of P.orientalis leaves,this study is intended to provide reference for the research,development and utilization of P.orientalis.

Regeneration Characteristics and Spatial Pattern of <i>Platycladus orientalis</i>in Mount Tai, China

Platycladus orientalis is one of the main tree species in Mount Tai, and its sustainable development is of great significance to the protection and development of the forest ecological environment of Mount Tai. In this study, a representative sample plot of Platycladus orientalis with a size of 30 m * 20 m was selected on Mount Tai. The growth and distribution of the parent trees and seedlings of Platycladus orientalis were investigated in the sample plots. The results showed that both the mother cypress trees and seedlings inside the plot present an aggregated distribution pattern within a certain scale, which conforms to the distribution of most natural communities;and the mother cypress can promote seedlings within a certain scale. Although Platycladus orientalis has good natural regeneration ability, it is difficult to succeed in understory regeneration solely relying on natural fertility, and it is not conducive to the long-term stable development of forest stands. Therefore, the thinning of Platycladus orientalis and the adjustment of the forest stand structure and artificial promotion of natural regeneration can not only reduce operating costs, but also conform to the idea of forest near-natural management and maintain sustainable forest development.

Cone and Ovule Development in Platycladus orientalis (Cupressaceae)

Seed cone in Platycladus orientalis (L.) France consists of four or five pairs of decussate bracts. Usually, two pairs of the fertile bracts in the middle of the cone subtend six ovules, which initiate in an acropetal manner. Only one ovule presents on each of the upper fertile bract, while two ovules initiate from a common primordium in the axil of lower bracts. In Beijing, most female cones initiated in July. All parts of the cone formed before dormancy, which occurred during November to the next January. After pollination in March, bract morphology changed dramatically; intercalary growth of the bract base formed a conspicuous protuberance, in which inverted vascular system developed. Furthermore, ovules on different pairs of bracts initiated in an acropetal manner and two ovules in each lower fertile bract initiated from a common primordium, which was different from the basipetal initiation of ovules and independently formed single ovule as reported by Takaso in Calltris

Platycladus orientalis shells promote melanogenesis via p38,AKT and Wnt/β-catenin signaling pathways

Background:Platycladus orientalis,which has been employed in traditional Chinese medicine for cool blood,antibacterial,promotion of hair growth and therapy of poliosis for centuries.However,there have been few reports focusing on Platycladus orientalis shells treating pigmentary disorders.Methods:In present study,gas chromatography–mass spectrometry was applied to analyzing the volatile composition of Platycladus orientalis shells and cellular metabolism.Experiments in vivo were carried out to evaluate the effect of Platycladus orientalis shells treating pigmentation disorders in C57BL/6J mice.Results:Our results indicated that cedrol occupied the largest percentage in Platycladus orientalis shells(17.1%).Meanwhile,Platycladus orientalis shells up-regulated the content of palmitic acid and increased melanin content and tyrosinase activity.Its mechanism possibly involved in the inhibiting phosphorylation of AKT and β-catenin,increasing phosphorylation of p38 to promote microphthalmia-associated transcription factor expression.The animal experiment also proved that Platycladus orientalis shells promoted melanogensis and hair blacken in C57BL/6J mice.Conclusion:All in all,Platycladus orientalis shells potentially promoted melanogenesis in vitro and in vivo.Cedrol was regarded as the main active substance in Platycladus orientalis shells.Therefore,it could be used for treatment of pigmentary disorders under safe concentration in the prospective application.

Comparison of host volatiles under different physiological states and electroantennogram responses of Semanotus bifasciatus (Motschulsky) to these volatiles

Based on an analytical TCT-GC/MS method, volatile compounds of branches of Platycladus orientalis under three physiological states （healthy, weak and baited trees） were analyzed. The results showed that α-pinene, β-phellandrene, 3-careen, limonene and thujopsene were released under all three physiological states. There were other kinds of volatiles released from branches of weak P. orientalis trees, such as camphene, γ-terpinene, （＋）-4-carene and cedrene, but these four volatiles compounds were not released from the branches of healthy P. orientalis. Volatile components from the physically damaged branches of P. orientalis had changed. β-terpinene, mycrene, isocaryophillene and caryophyllene were identified in both healthy and weak branches of P. orientalis. Only cedrene was identified in the baited wood. Electroantennogram （EAG） tests were conducted with nine volatile compounds from the branches of P. orientalis. Antennnae of male and female Semanotus bifasciatus （Motschulsky） were highly sensitive to these nine volatile compounds. Cedrene elicited the strongest response, whereas β-terpinene the lowest. Males and females showed no signifi-cant difference in their EAG responses to the nine volatile compounds.

黄土高原半干旱区侧柏(Platycladus orientalis)树干液流动态

应用热扩散式树干茎流计(TDP)于2008年4～10月对黄土高原安塞县侧柏人工林树干液流速率进行了连续测定,并对周围气象、土壤水分等多个环境因子进行了同步测定。结果表明:侧柏在不同月份晴天树干液流速率变化具有明显的昼夜节律性,呈单峰曲线;且各月液流速率日均值受土壤供水水平限制总体上呈下降趋势,即4月份最大,为0.00135cm.s-1;10月份最小为0.00011cm.s-1;树干液流速率与光合有效辐射、大气温度、水汽压差呈极显著正相关,与相对湿度呈负相关,其相关程度:光合有效辐射>水汽压差>大气温度>相对湿度,并可用线性表达式来估算;侧柏边材面积和地径呈幂指数关系,并以此结合密度估算出样地侧柏人工林的边材面积为4.65m2,最终估算出侧柏人工林生长季总耗水量为1159.6t.hm-2。

嵩山侧柏(Platycladus orientalis)人工林恢复过程中物种多样性变化研究

采用空间代替时间的方法,通过样方调查对嵩山侧柏人工林恢复过程中不同群落的物种多样性变化进行了研究.结果表明,在侧柏人工林恢复过程中,灌木层和草本层的物种丰富度和多样性变化规律相似,物种丰富度(Margalef指数)和物种多样性(Shannon-Wiener指数及Simpson指数)都表现为“低→高→低→高”的变化趋势,在波动中逐渐增加;物种均匀度(Pielou指数)却没有明显的增加趋势.不同恢复阶段因人工林环境条件的改变导致林下不断出现因喜阳和耐荫物种的交替而出现的物种消亡和更新,个体数目分布的不均使物种均匀度显示出较大的波动性.总体来看,侧柏人工林在恢复过程中是朝着有利于物种多样性恢复的方向发展.

Relationship between effective solar radiation and sap flow process during an entire growing season in Western Mountains of Beijing

In order to explore the relationship between the time processes of solar radiation and sap flow, sap flow velocity （SFV） of Platycladus orientalis and Pinus tabulaeformis, effective solar radiation （ESR） and other environmental factors were synchronously monitored for one year in the Beijing Western Mountains by using a thermal dissipation probe （TDP） system and an automatic weather station. Results showed significant differences between changes in diurnal characteristics of ESR and sap flow in sunny days during three seasons. Starting times of sap flow occurred generally 1.5-3 hours later than those of solar radiation and there were small differences between Platycladus orientalis and Pinus tabulaeformis. But peak times and stopping times of sap flow varied considerably with large contrasts in ESR. The duration of sap flow showed clear differences among the seasons owing to the variable rhythms of climate factors in Beijing. Fluctuation amplitude in the duration of sap flow remained relatively stable during the autumn but changed greatly during spring and summer. Changes in diurnal sap flow velocity of both Platycladus orientalis and Pinus tabulaeformis were about 0-3 hours later than those of ESR but with the same configuration. The start of sap flow was mainly induced by the sudden intensification of ESR （sunrise effect）. Seasonal models of SFV indicated that a cubic equation had the best fit. It was more practical to simulate seasonal water consumption models of trees with ESR. In further investigations, these models should be optimized.

LAI and Leaf Biomass Allometric Equations for Three Common Tree Species in a Hyrcanian Temperate Forest

Despite the importance of Hyrcanian forests for biodiversity conservation, a few studies with biomass destruction has been done to predict biomass and carbon pools from this forest and there is a lack of knowledge in our country. Biomass and leaf area index (LAI) are important variables in many ecological and environmental applications and forest management. In this paper, allometric biomass and leaf area equations were developed for three common Hyrcanian tree species, Oriental Beech (Fagus orientalis Lipsky), Hornbeam (Carpinus Betulus Lipsky) and Chestnut- leaved Oak (Quercus castaneifolia C. A. Mey). To evaluate and estimate the leaf biomass and leaf area index of Oriental Beech, Horbeam and Chestnut-leaved Oak, 21, 27 and 17 individuals were selected and felled down, respectively. Tree characteristics such as diameter at breast height, total height, crown length and perpendicular diameters were measured. Destructive sampling was applied for determination of leaf biomass and LAI. Allometric equations were calculated for estimation of leaf biomass and LAI using simple linear regression and nonlinear regression analysis. The equations were compared based on several modelling parameters. Model comparison and selection were based on R2, Akaike’s information criterion (AIC), prediction error sums of squares, model standard error estimate (SEE), ΔAIC, and a correction factor. Based on the results, the mean values of leaf area, leaf biomass and LAI for Oriental Beech were 53.05 cm2, 0.176 gr, 2.16, for Hornbeam were 27.2 cm2, 0.128 gr, 1.13 and for Chestnut-leaved Oak were 62.419 cm2, 0.401 gr, 2.26, respectively. The highest significant correlation for Oriental Beech was found between LAI and total height (R2adj= 0. 931), the highest significant correlation for Hornbeam was found between LAI and Dbh (R2adj = 0. 956) and the highest significance for Chestnut-leaved Oak was found between LAI and SqrtDbh (R2adj = 0. 956). Also, the best equations were obtained by means of an exponential regression model for Oriental Beech, the Log-transformed regression model for Hornbeam and of a transformed regression model for Chestnut-leaved Oak.

不同产地侧柏叶中无机元素的含量测定及评价

采用电感耦合等离子体质谱法(ICP-MS)测定不同产地侧柏[Platycladus orientalis(L.)Franco]叶中无机元素含量,并进行方法学验证,采用SPSS软件进行聚类分析和主成分分析,对其特征元素进行评价。结果表明,标准样品中26种元素的线性关系良好,相关系数(R^(2))≥0.9953,各元素的检出限在0.0020~4.2226 ng/mL,精密度、稳定性、重复性符合要求,各元素的平均加样回收率在84.1%~123.6%,相对标准偏差在0.7%~4.5%;28批侧柏叶样品中检测出24种无机元素,含量差异较大,其中,侧柏叶样品K、Ca、Mg的含量均超过1000 mg/kg,Cd、As、Hg、Cu含量均在《中华人民共和国药典:一部》规定的限度范围内,Pb含量为0.602~9.337 mg/kg,有6批侧柏叶样品超出限度;主成分分析显示Fe、Ti、Ca、Ni、Al、Mn、Zn、K为侧柏叶的主要特征性元素;聚类分析显示,地理位置相近的产地能较好地聚为一类,表明侧柏叶中无机元素含量存在明显的地域特征。建立的方法操作简便,分析速度快,灵敏度高,可用于侧柏叶中无机元素含量的测定。

基于原位EIS参数与改进BiGRU算法的侧柏苗木生长预测研究

侧柏苗木的生长预测对于苗木未来的出圃时间、调整现有苗木的种植方案等方面意义重大。本文运用原位电阻抗图谱技术发现4 kHz下的阻抗相位角、400 kHz下阻抗正切值可以表示侧柏根系的健康程度,与茎粗、株高、分枝数等指标共同构成代表侧柏苗木质量的特征向量;同时,设计了基于多维双向的时空融合模型(CNN-DBiGRU-WBLS),该模型可以有效解决多因素输入下未来4周、8周、16周的侧柏生长数据预测问题,Willmott一致性指数(WI)值达到0.993、0.975和0.948,比CNN-BiGRU、CNN-LSTM、CNN-BiLSTM和CNN-GRU等现有模型WI最优值提升了0.6%、1.1%和1.5%以上。试验结果表明,本文算法对侧柏苗木生长指标具有较好的预测性能。

林分密度对北京石质山地侧柏人工林碳氮磷化学计量和养分再吸收的影响

【目的】探讨北京石质山地不同林分密度对侧柏人工林C、N、P化学计量特征的影响,以及养分再吸收与林分密度的关系,旨在揭示林分密度变化下侧柏人工林主要养分相互作用与制约规律,为侧柏人工林经营管理提供科学依据。【方法】以不同密度侧柏人工林为研究对象,分析其鲜叶、凋落叶和土壤C、N、P化学计量特征及养分再吸收规律。【结果】(1)林分密度对土壤–鲜叶–凋落叶C、N、P化学计量影响不同,鲜叶N、P和N:P以及凋落叶P含量随着密度的增加逐渐降低,而鲜叶C∶N和C∶P总体呈升高趋势。凋落叶C∶N和C∶P随着密度的增大呈升高。(2)土壤的N和P含量随密度先升后降;林分密度和土壤因素的交互作用仅对鲜叶N和凋落叶P有显著影响;(3)不同林分密度的侧柏林N再吸收率明显低于P再吸收率,N再吸收率为18.03%~32.15%,P再吸收率为58.87%~60.13%。【结论】合理的林分密度能缓解侧柏人工林养分限制以及提高N、P重吸收能力。未来应注重林分密度调整、增加阔叶树种比例、实施抚育剩余物处理等措施以改善侧柏人工林养分限制状况。

响应面法优化侧柏叶精油的超声辅助水蒸气蒸馏提取工艺

以侧柏叶精油提取率为评价指标,选取超声功率、超声时间、液料比和提取时间为考察因素,通过单因素实验及响应面法优化了侧柏叶精油的超声辅助水蒸气蒸馏提取工艺。结果表明,各因素对侧柏叶精油提取率影响的大小顺序为:提取时间>超声功率>超声时间>液料比;确定最佳提取工艺为:超声功率80 W、超声时间32 min、液料比14∶1 (mL∶g)、提取时间6 h,在此条件下,侧柏叶精油提取率为0.821%,与预测值(0.817%)接近。该方法操作简单、稳定可靠,为侧柏叶精油的进一步开发利用提供了理论依据。