Effects of thinning on the understory light environment of different stands and the photosynthetic performance and growth of the reforestation species Phoebe bournei

Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei seedlings.The canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following thin-ning.Thinning improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light environ-ment.Under the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral composition.P.bournei photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light environment.In a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal conductance.As a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of P.bournei seedlings,and a reduction increased light absorption and use capacity and height:diameter ratios.The growth advantage transformed from diameter to height,enabling seedlings to access more light.Our findings suggest that the regeneration of shade-tolerant species such as P.bournei could be enhanced if a targeted approach to thinning based on stand type was adopted.

Genome wide investigation of Hsf gene family in Phoebe bournei:identification,evolution,and expression after abiotic stresses

Heat shock transcription factors(Hsfs)have important roles during plant growth and development and responses to abiotic stresses.The identification and func-tion of Hsf genes have been thoroughly studied in various herbaceous plant species,but not woody species,especially Phoebe bournei,an endangered,unique species in China.In this study,17 members of the Hsf gene family were identi-fied from P.bournei using bioinformatic methods.Phyloge-netic analysis indicated that PbHsf genes were grouped into three subfamilies:A,B,and C.Conserved motifs,three-dimensional structure,and physicochemical properties of the PbHsf proteins were also analyzed.The structure of the PbHsf genes varied in the number of exons and introns.Pre-diction of cis-acting elements in the promoter region indi-cated that PbHsf genes are likely involved in responses to plant hormones and stresses.A collinearity analysis dem-onstrated that expansions of the PbHsf gene family mainly take place via segmental duplication.The expression levels of PbHsf genes varied across different plant tissues.On the basis of the expression profiles of five representative PbHsf genes during heat,cold,salt,and drought stress,PbHsf pro-teins seem to have multiple functions depending on the type of abiotic stress.This systematic,genome-wide investigation of PbHsf genes in P.bournei and their expression patterns provides valuable insights and information for further func-tional dissection of Hsf proteins in this endangered,unique species.

Effects of Shading Degree on Storage Rate and Growth of Phoebe bournei Seedlings in Fields

In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showed that the storage rate is growing upon shading degree. In the research, for example, storage rate reached the peak with the shading degree at 70%, and only 42.2% with shading degree at 0. In addition, seedling height and ground diameter showed extremely significant differences among treatments, and the treatment with shading degree at 60% was the best.

Growth Performance of Phoebe bournei Generations in Seedling Stage

[Objective] The aim was to explore growth performance of Phoebe bournei in seedling stage.[Method] Based on 17 superior plus trees of Phoebe bournei,a seedling cultivation test was conducted in Jindong Forest Farm in Yongzhou,Hunan Province,exploring growth indices and analyzing seedling height and ground diameter.[Result] As per the selection rate at 20％,PB17,PB9 and PB12 were selected from the 17 species.Specifically,the seedling height averaged 36.52 cm of the selected three seedlings,which was higher by 16.1％ compared with average of 17 species （31.45％）.As for ground diameter,the selected species averaged 2.6 mm,which was higher （13.0％） compared with the average level （2.3 mm）.[Conclusion]Both of seedling height and ground diameter reached extremely significant differences,which indicated that half-sib families of Phoebe bournei have rich variations,with selection and breeding potential.

Nutritional Properties and Fertilizer Demand Rules of Young Phoebe bournei Forest

This study aimed to investigate the absorption characteristics of nitrogen, phosphorus, potassium, calcium and magnesium and rules in fertilizer demand by young Phoebe bournei forest. The results showed that the nitrogen, phosphoruS, potassium and magnesium contents in young Phoebe bournei leaves were increased with the proceeding of growth, but the calcium content was increased. During the growth period, the nitrogen, phosphorus, potassium and magnesium contents were relatively high in June, July and August. This study will help to understand the nu- tritional characteristics and fertilizer demand rules of young Phoebe boumei forest, thereby providing scientific theoretical guidance for application of fertilizer in Phoebe bournei.

Study on Grading Standard for One-Year-Old Container Seedling Quality of Phoebe zhennan

In order to improve the survival rate of planting seedlings of Phoebe zhen-nan, the grading standard for one-year-old container seedlings of Phoebe zhennan was developed by using cluster analysis. The results showed that the quality of Phoebe zhennan container seedlings could be estimated from seedling height and ground diameter. The Phoebe zhennan container seedlings were divided into 3 grades： Grade 1 （seedling height ≥ 38 cm; ground diameter ≥ 0.65 cm）, Grade 2 （31.7 cm ≤ seedling height 〈 38 cm; 0.56 cm ≤ ground diameter 〈 0.65 cm） and Grade 3 （seedling height 〈 31.7 cm; ground diameter 〈 0.56 cm）.

Study on the Landscape Application of Phoebe zhennan in Chengdu Campagna

On the basis of introducing the characteristics and ornamental values of Phoebe zhennan and theirs resources in Chengdu Campagna,taking their application for example,this research discusses their functions in landscaping and the layout in afforestation,and analyses its application prospect,in order to guide the striving direction for garden workers.

Phenotypic variation in Phoebe bournei populations preserved in the primary distribution area

Phoebe bournei（Hemsl.） Yang is a rare and protected plant in China. This study was conducted to determine the phenotypic variation in this species and to document phenotypic variation within and among populations of P. bournei. Nested analysis of variance, coefficient of variation, multiple comparisons, principal component analysis（PCA） and correlation analysis were used to analyze ten phenotypic traits in ten natural populations of P.bournei from both the northeastern and the primary region of the range of this species. Significant differences among and within populations were observed in leaf and seed phenotypic traits. Variation among populations（34.92%）was greater than that within populations（26.19%）. The mean phenotypic differentiation coefficient was 53.77% among populations, indicating that variation among populations comprised the majority of the phenotypic variation of P. bournei. The coefficient of variance（CV） of ten traits varied from 6.44 to 18.45%, with an average of 12.03%.The CV of leaf traits among populations（15.64%） was higher than that of seed traits（8.60%）, indicating that seed traits were more stable. The results from CV and PCA indicated that leaf area, leaf length and thousand seed weight were the main factors accounting for the observed phenotypic variations. Significant or highly significant correlations were observed among most leaf and/or in seed phenotypic traits, whereas no significant correlations were observed between phenotypic traits and geographic factors.Based on cluster analysis, the ten populations can be divided into three clusters. These clusters were not a result of geographic distances.

Comparative analysis of modern and ancient buried Phoebe zhennan wood:surface color,chemical components,infrared spectroscopy,and essential oil composition

We compared the chemical components and essential oils of ancient buried Zhennan（Phoebe zhennan）wood with those in samples from living trees.After removal of the carbon layer the recovered Zhennan exhibited a dark green color,which differed from the yellow color of the living samples.Low molecular weight components（including hot-water and toluene-alcohol extractives）,hemicellulose,and 1 % Na OH solubility in the recovered wood were greatly degraded.Degradation of cellulose was minor.Moreover,the ancient wood had somewhat more klason lignin than the modern wood.Fourier transform infrared（FTIR） analysis gave further evidence on the differences in chemical components.According to the GC–MS results,naphthalene derivatives were detected in the essential oils from both the modern and recovered wood.The delicate fragrance of the modern and recovered wood may be attributed to the aromatic constituents as identified by GC–MS.

Exogenous Glycine Betaine Reduces Drought Damage by Mediating Osmotic Adjustment and Enhancing Antioxidant Defense in Phoebe hunanensis

Drought stress negatively impacts growth and physiological processes in plants.The foliar application of glycine betaine(GB)is an effective and low-cost approach to improve the drought tolerance of trees.This study examined the effect of exogenously applied GB on the cell membrane permeability,osmotic adjustment,and antioxidant enzyme activities of Phoebe hunanensis Hand.-Mazz under drought stress.Two levels(0 and 800 mL)of water irrigation were tested under different applied GB concentrations(0,50,100,and 200 mM).Drought stress decreased the relative water content by 58.5%while increased the electric conductivity,malondialdehyde,proline,soluble proteins,soluble sugars,and antioxidant enzyme activities(superoxide dismutase,catalase,peroxidase)by up to 62.9%,42.4%,87.0%,19.1%,60.5%,68.3%,71.7%,and 83.8%,respectively,on the 25^(th) day.The foliar application of GB,especially at 100 mM,increased the relative water content of P.hunanensis leaves under drought stress.The concentration of GB from 50 to 100 mM effectively alleviated the improvement of cell membrane permeability and inhibited the accumulation of membrane lipid peroxidation products.Under drought stress,the concentrations of proline,soluble proteins,and soluble sugars in the leaves of P.hunanensis increased as the applied GB concentration was increased and the water stress time was prolonged.Exogenously applied GB decreased oxidative stress and improved antioxidant enzyme activities as compared with treatments without GB application.Furthermore,the physiological and biochemical indexes of P.hunanensis showed a certain dose effect on exogenous GB concentration.These results suggest that GB helps maintain the drought tolerance of P.hunanensis.

Phenological Observation of Man-made Phoebe bournei Forests

[Objective] The aim was to research annual shoot increments, blooming and fruit-bearing times, and sprouting ratio of man-made Phoebe boumei.[Methed] Phenological observations of Phoebe boumei blooming were conducted as per method of phytocoenology. [Result] Phoebe bournei shot three times per year, and autumn shoots proved the largest, followed by summer shoots and spring sprouts. Sprouts shaped from late April to early May, and bloomed from late April to middle May; young fruits grew from middle May to late May and matured from middle De- cember to late December. Thousand-seed weight of fruits reached 487-503 g, and averaged 496 g; thousand-seed weight of seed was 265-275 g and averaged 269 g; sprouting rate of seed in room was in 84.8%-88.5% and averaged 86.5%; sprouting rate of seeds in fields was in 68.4%-72.6%, and averaged 70.4%. [Conclusion] The research provides references for man-made Phoebe bournei forests.

Study on the Structural Characteristics and Physical and Mechanical Properties of Phoebe bournei Thinning Wood

The artificial afforestation of precious Phoebe bournei has been carried out in China.During the cultivation process,thinning wood will be produced.The properties of thinning wood might vary greatly with matured wood and require evaluation for better utilization.The objective of the present study aims to determine the wood structure,fiber morphology,and physical and mechanical properties of the Phoebe bournei thinning wood to help us understand the wood properties and improve its utility value.Three 14-year-old Phoebe bournei were cut from Jindong Forestry Farm of Hunan Province,China.The wood structure and fiber morphology were observed and analyzed with a light microscope and scanning electron microscope.The physical and mechanical properties were tested according to the Chinese national standards.The results showed as follows:(1)The Phoebe bournei thinning wood has a beautiful wood figure and fine texture,whereas the heartwood has not yet formed.(2)It is a diffuse-porous hardwood with small and less pores as well as fine wood rays.(3)The wood fiber is medium length and extremely thin wall thickness.(4)It is low in density and has excellent dimensionally stability.(5)The wood mechanical properties belong to the low to medium class and the comprehensive strength of wood belongs to the medium-strength class.It is concluded that Phoebe bournei thinning wood is suitable for wood carving,handicraft,high-end furniture,and decorative furniture parts.

Study on Growth Rules and Photosynthetic Physiology of Biennial Container Seedlings and Bare Root Seedlings of Phoebe

Transplantation experiment was carried out using biennial container seedlings and bare root seedlings of Phoebe zhennan S. Lee as materials. In the experiment,it measured the growth indicators such as the seedling height,basal diameter,and number of branches and leaves. Besides,it also measured net photosynthetic rate( Pn),transpiration rate( Tr),stomatal conductance( Gs),intercellular CO_2 concentration( Ci) and soluble sugar,soluble protein,malondialdehyde( MDA) content,superoxide dismutase activity and root activity. The results indicated that the growth indicators of the Phoebe container seedlings performed the best in the plant height,basal diameter,and number of branches and leaves; photosynthetic capacity was the strongest,and the fertilization could enhance the photosynthetic capacity of seedlings; soluble sugar,soluble protein content,superoxide dismutase activity and root activity of Phoebe container seedlings were higher than that of bare root seedlings.

Comparision of the Leaf Morphology of Two Phoebe bournei Varieties

To study the leaf variation and morphological diversity of Phoebe bournei,the leaves of two leaf types and one wild type in the same growth environment,which were marked as Type A,B,and C with wild type being marked as B,were used as testing materials.40 healthy mature leaves collected from healthy plants were taken as research samples and phenotypic characteristics,such as leaf shape,leaf length,leaf width,leaf area,and leaf vein were observed and analyzed.The leaves of Type A were oblanceolate,the base of the leaves was gradually narrow,and the tip of the leaves was gradually sharp.There were white pubescences on the back of the leaves,which were arranged in order.The pubescences were evenly distributed on the mesophyll and vein,in the same direction.The length,width,perimeter,and area of the leaves were smaller than those of the other two types.The leaves of Type B were narrow,oblanceolate,wedge-shaped at the base,long acuminate at the tip,with yellow brown villi on the back of the leaves,mainly distributed along the vein and the grid vein between the veins;the villi on the main veins were longer,and the villi between the mesophylls were less numerous and shorter.The length,perimeter,and aspect ratio of the blade were the largest of the three types and the whole blade was slender.Type C leaves were elliptical with a nearly truncated base and a sharp tip.There were white pubescences on the back of the leaves and less mesophyll pubescence along the veins.The length-width ratio of the blade was small,the width was large,and the whole blade was round.There were significant differences among the three leaf types of P.bournei and preliminary judgement was that Type A and Type C were spontaneous mutants.

浅析Phoebe Philo的CELINE时期中的女性主义

通过分析Phoebe Philo在CELINE任职期间的服装,了解Phoebe Philo在CELINE所构建的由真实生活所驱使的女性的服装设计。从女性主义出发,分析其可行性和必要性。

基于SSR分子标记的闽楠(Phoebe bournei)核心种质的构建

为更好地发掘和利用现有闽楠种质资源,本研究利用7个SSR位点对江西和福建16个闽楠群体的237份材料进行基因型分析,采用逐步聚类(随机取样策略,位点优先取样策略)和模拟退火算法(等位基因数目最大化策略,遗传距离最大化策略)4种取样方法构建闽楠核心种质,并将各遗传多样性指标进行分析。结果表明:7个SSR位点共检测到50个等位基因,平均为7.143,平均有效等位基因为2.115,Shannon信息指数为0.778,观测杂合度为0.302,期望杂合度为0.442。基于逐步聚类方法构建的核心种质相较于基于模拟退火算法构建的核心种质各遗传参数指标都相对较高。对其进行t检验后,选择以基于逐步聚类位点优先取样策略在25%的取样比例下选取的种质为核心种质,其等位基因数、平均有效等位基因数、多态性位点百分率、Shannon多样性指数的保留率分别为初始种质的98%、104.92%、90.09%、97.94%。筛选出的59份核心种质材料能够较好地代表闽楠种质资源的遗传多样性,为闽楠的种质资源保存提供科学依据。

The chromosome-scale genome of Phoebe bournei reveals contrasting fates of terpene synthase (TPS)-a and TPS-b subfamilies

Terpenoids,including aromatic volatile monoterpenoids and sesquiterpenoids,function in defense against pathogens and herbivores.Phoebe trees are remarkable for their scented wood and decay resistance.Unlike other Lauraceae species investigated to date,Phoebe species predominantly accumulate sesquiterpenoids instead of monoterpenoids.Limited genomic data restrict the elucidation of terpenoid variation and functions.Here,we present a chromosome-scale genome assembly of a Lauraceae tree,Phoebe bournei,and identify 72 full-length terpene synthase(TPS)genes.Genome-level comparison shows pervasive lineage-specific duplication and contraction of TPS subfamilies,which have contributed to the extreme terpenoid variation within Lauraceae species.Although the TPS-a and TPS-b subfamilies were both expanded via tandem duplication in P.bournei,more TPS-a copies were retained and constitutively expressed,whereas more TPS-b copies were lost.The TPS-a genes on chromosome 8 functionally diverged to synthesize eight highly accumulated sesquiterpenes in P.bournei.The essential oil of P.bournei and its main component,b-caryophyllene,exhibited antifungal activities against the three most widespread canker pathogens of trees.The TPS-a and TPS-b subfamilies have experienced contrasting fates over the evolution of P.bournei.The abundant sesquiterpenoids produced by TPS-a proteins contribute to the excellent pathogen resistance of P.bournei trees.Overall,this study sheds light on the evolution and adaptation of terpenoids in Lauraceae and provides valuable resources for boosting plant immunity against pathogens in various trees and crops.

Where Is Phoebe?

1．请小朋友先把眼睛闭上,爸爸躲在家中的某处 (例如bedroom卧室,bathroom浴室,kitchen 厨房,living room客厅,garden花园)。(如图1) 2．爸爸藏好后,请小朋友问妈妈“Where is Father? Is he in the kitchen?(爸爸在哪里？他在厨房 吗？)”妈妈视情况回答“Yes,he is．(是的,他 在。)”或“No,he isn’t．(不,他不在。)”。 (如图2)

CaCl_2和水杨酸对桢楠和闽楠抗寒性的影响

为探讨自然低温下不同浓度的氯化钙(CaCl2)、水杨酸(SA)对闽楠(Phoebe bournei)、桢楠(Phoebe zhennan)2种植物抗寒性的影响,以这2种植物一年生苗为试验材料,测定闽楠和桢楠叶片的相对电导率、丙二醛含量、可溶性糖含量、可溶性蛋白含量、过氧化物酶活性、叶绿素含量等指标的变化情况。结果表明,1mmol/L的SA溶液降低闽楠幼苗叶片的电导率、丙二醛含量的效果较为显著,提高闽楠和桢楠幼苗叶片可溶性糖、可溶性蛋白、叶绿素含量和过氧化物酶活性的效果较为显著。综合比较得出,SA处理效果优于CaCl2,以1mmol/L的SA溶液提高闽楠和桢楠幼苗叶片抗寒能力效果最好。

不同土壤条件下闽楠幼苗生长量研究

为探明不同土壤条件下闽楠(Phoebe bournei)幼苗的生长情况,以一年生闽楠幼苗为试材,分别测定8块不同土壤条件下闽楠春梢、夏梢及秋梢生长量。结果表明,闽楠春梢生长量与全氮呈线性关系,秋梢生长量与全磷呈线性关系;受温度与水分制约,闽楠夏梢生长量与氮、磷、钾之间无明显关系。