Variation analyses of growth and wood properties of Larix olgensis clones in China

The growth traits(tree height, diameter at breast height, and stem straightness degree) and wood properties[wood density(WD), fiber length, fiber width, ash content(AC), lignin content, cellulose content, hemicellulose content(HEC), and holocellulose content] of 208 26-yearold Larix olgensis clones were analyzed. Except for WD and AC, there were significant differences(p \ 0.01) for all traits among clones. The phenotypic coefficient of variation and repeatability of all traits were 9.34–35.33%and 0.218–0.930, respectively. Tree height and diameter at breast height showed significant positive correlation;however, the correlation coefficients among growth characteristics and wood properties were mostly not significant.Ten clones(L70, L56, L82, L90, L59, L91, L61, L92, L86,and L64) were selected as excellent clones under a selection rate of 5%, using tree height, diameter at breast height,and stem straightness degree as evaluation indexes, providing genetic gains of 28.69, 17.96, and 0.67%, respectively. Ten clones(L88, L305, L59, L66, L253, L304,L277, L298, L248, and L293) were selected as excellent clones using wood properties as an evaluation index, with a selection rate of 5%, providing genetic gains in WD, fiber length, fiber width, cellulose content, and HEC of 4.14,3.64, 9.28, 6.77, and 9.61%, respectively. This study provides a theoretical basis for selecting excellent L. olgensis clones.

Nonlinear mixed-effects height to crown base and crown length dynamic models using the branch mortality technique for a Korean larch( Larix olgensis ) plantations in northeast China

Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and shape.The majority of crown models are static models based on tree size and stand characteristics from temporary sample plots,but crown dynamic models has seldom been constructed.Therefore,this study aimed to develop height to crown base(HCB)and crown length(CL)dynamic models using the branch mortality technique for a Korean larch plantation.The nonlinear mixed-eff ects model with random eff ects,variance functions and correlation structures,was used to build HCB and CL dynamic models.The data were obtained from 95 sample trees of 19 plots in Meng JiaGang forest farm in Northeast China.The results showed that HCB progressively increases as tree age,tree height growth(HT growth)and diameter at breast height growth(DBH growth).The CL was increased with tree age in 20 years ago,and subsequently stabilized.HT growth,DBH growth stand basal area(BAS)and crown competition factor(CCF)signifi cantly infl uenced HCB and CL.The HCB was positively correlated with BAS,HT growth and DBH growth,but negatively correlated with CCF.The CL was positively correlated with BAS and CCF,but negatively correlated with DBH growth.Model fi tting and validation confi rmed that the mixed-eff ects model considering the stand and tree level random eff ects was accurate and reliable for predicting the HCB and CL dynamics.However,the models involving adding variance functions and time series correlation structure could not completely remove heterogeneity and autocorrelation,and the fi tting precision of the models was reduced.Therefore,from the point of view of application,we should take care to avoid setting up over-complex models.The HCB and CL dynamic models in our study may also be incorporated into stand growth and yield model systems in China.

Larix olgensis growth-climate response between lower and upper elevation limits:an intensive study along the eastern slope of the Changbai Mountains,northeastern China

Larix olgensis is a dominant tree species in the forest ecosystems of the Changbai Mountains of northeast China.To assess the growth response of this species to global climate change,we developed three tree-ring width and biomass chronologies across a range of elevations in the subalpine forests on the eastern slope of the Changbai Mountains.We used dendroclimatic analyses to study key factors limiting radial growth in L.olgensis and its variation with elevation.The statistical characteristics of chronologies suggested that elevation is a determinant of tree growth patterns in the study area.Response function analysis of chronologies with climate factors indicated that climate–growth relationships changed with increasing elevation:tree growth at high elevation was strongly limited by June temperatures of the previous year,and as elevation decreases,the importance of temperature decreased;tree radial growth at mid-elevation was mainly controlled by precipitation towards the end of the growing season of the current year.Biomass chronologies reflected a stronger climatic signal than tree-ring width chronologies.Spatial correlation with gridded climate data revealed that our chronologies contained a strong regional temperature signal for northeast China.Trees growing below timberline appeared to be more sensitive to climate,thus optimal sites for examining growth trends as a function of climate variation are considered to be just below timberline.Our study objective was to provide information for more accurate prediction of the growth response of L.olgensis to future climate change on the eastern slope of the Changbai Mountains,and to provide information for future climate reconstructions using this tree species in humid and semi humid regions.

Characteristics of soil organic carbon mineralization and influence factor analysis of natural Larix olgensis forest at different ages

Soil organic carbon(SOC)mineralization is closely related to carbon source or sink of terrestrial ecosystem.Natural stands of Larix olgensis on the Jincang forest farm,Jilin Province were selected to investigate the dynamics of SOC mineralization and its correlations with other soil properties in a young forest and mid-aged forest at soil depths of 0–10,>10–20,>20–40 and>40–60 cm.The results showed that compared with a mid-aged forest,the SOC stock in the young forest was 32%higher.Potentially mineralizable soil carbon(C0)in the young forest was 1.1–2.5 g kg^-1,accounting for 5.5–8.1%of total SOC during the 105 days incubation period and 0.3–1.5 g kg^-1 in the mid-aged forest at different soil depths,occupying 2.8–3.4%of total SOC.There was a significant difference in C0 among the soil depths.The dynamics of the SOC mineralization was a good fit to a three-pool(labile,intermediate and stable)carbon decomposition kinetic model.The SOC decomposition rate for different stand ages and different soil depths reached high levels for the first 15 days.Correlation analysis revealed that the C0 was significantly positively related with SOC content,soil total N(TN)and readily available K(AK)concentration.The labile soil carbon pool was significantly related to SOC and TN concentration,and significantly negatively correlated with soil bulk density.The intermediate carbon pool was positively associated with TN and AK.The stable carbon pool had negative correlations with SOC,TN and AK.

COMPARATIVE STUDY ON DROUGHT RESISTANCE OF LARIX OLGENSIS HENRY AND PINUS SYLVESTRIS VAR.MONGOLICA(Ⅰ)──THE INFLUENCE OF SOIL WATER CONTENT ON SEEDLINGS PLANTING IN FLOWERPOT

Water potential (φ w .) and net photosynthetic rate (Pn) of Larix olgensis and Pinns.sylvestris var. mongolica deercased with the deerease of soil water content φw and Pn of L.olgensis changed hardly during the first 9 davs after stopping watering, then deereased sharply at the 10th dav Pn of P sylvestris var mongolica deereased slightly during the lirst 8 days, then deereased sharply at the 9th day Their respiration rate, chlorophyll content and their a/b ratio changed hardly. The tollowing 3 conclusions were obtained and discussed exhaustively . (Ⅰ) φ w can be used to direct watering as a sensitive index of judging whether L. olgensis and P.sylvestris var. mongolica lacking water (2 )The deereasc of Pn of L. olgensis and P. sylvestris var. mongolica when drought had nothing to do with chlorophyll. (3) P. sylvestris var. mongolica had morphological drought resistance . while L,olgensis had physiological drought resistance, and their drought resistance was discnssed comparatively first time.

Screening and verification of the factors influencing somatic embryo maturation of Larix olgensis

With embryogenic callus of Larix olgensisis, we investigated the effects of inositol, glutamine, casein hydrolysate, carbohydrate, abscisic acid and silver nitrate concentration on the maturation of the somatic embryo.Three dominant factors emerged, and we developed a response surface model based on the Box-Behnken design.We defined the optimal conditions for the maturation of somatic embryos. The contents of abscisic acid, silver nitrate, sucrose and casein hydrolysis significantly affected the amount of maturing embryos, but inositol, maltose and glutamine had no effect. By establishing a response surface model with multiple factors, we predicted that the optimal number of L. olgensis somatic embryos was 204 ± 4 g^(-1) on basal medium, containing 18.28 mg L^(-1) abscisic acid,5.46 mg L^(-1) silver nitrate and 82.67 g L^(-1) sucrose. In the verification experiments, the addition of 20 mg L^(-1) abscisic acid, 5 mg L^(-1) silver nitrate and 80 g L^(-1) sucrose to BM yielded an average of 202.06 somatic embryos per gram. These results should guide large-scale breeding of L. olgensis.

A STUDY ON THE GEOGRAPHIC VARIATION ANDSELECTIONOFTHEBEST PROVENANCE OF LARIX OLGENSIS

On the basis of the results from the geographic provenance test of nine years old /arix olgensis in Liangshui Natural Reserve of our university, a study on the geographic varition and the primary selection of the best provenance of torix oIgensis was carried out. The main results are as follows: 1. The different provenances of Larix olgensis have rich and wide genetic variation, and exist a linear correlation with latitude and longitude in collection area. General trends are enumerated below: Provenances at lower latitude and more west longitude have lighter thousand seed weight. short growth period, higher increment, wide branches, rich leaves and crown as well as worst adaptabi llity. It is a dual-way variation along with two directions of latitude and longitude, and also embodies a change gradually in climate condition from south to north. The temperat ures in seed production site, especially the mean temperature in January and≥10℃ accumulated temperature, are important factors that produce geographic variation for larix olgensis. 2. The variation of different provenances in periodic biological phenomena and growth rhythm trends are that: ① both of the provenances from Changbai Mt. (Ⅲ) and Dashitou(Ⅳ) at low latitude belong to the centralized growth type, and have shout growth period, the difference between these two provenances is that the provenance from Changbai Mt. grows well in all time, Dashitou provennce is well only in later period; ②the provenance from Baidao Mt. (Ⅱ) at middle latitude belongs to even growth type and has longer grpwth period, this provenance has higher increment in early and later periods relatively; ③ Xiaobeihu provenance at high latitude is a growth type among Ⅱ Ⅲ and Ⅳ provenances and has a general growth period, the provenance grows better in middle time and worse in later time. 3. The best provenance in Liangshui Natural Reserve and its meighbourhood is Dashitou Procenance. which growth in height. diameter and volume has exceeded 16. 28%, 46. 27%, 30. 58%, 78. 20, 82. 00% as well as 392. 00% by comparison with the mean value of the contrast and the worst provenance respectively, The result from the height growth of three, five. seven and nine years old Larix olgensis by using the method of order correlation analysis demonstrates that it is possible to make early selection of the provenance. Meanwhile. data from juvenile and mature of larix olgensis plantation also prove the reliability of the early selection. 4. The provenance heritabilities of nine years old larix olgensis in Liangshui Natural Reserve are follows:The heritability of the height growth (h2)is 0. 79; The heritability of the diameter breast height (h2) is 0. 791; The geretic gain is 24. 5%and 40. 36% respectively.

Exogenous application of succinic acid enhances tolerance of Larix olgensis seedling to lead stress

Larix olgensis A. Henry(Changbai larch) is a productive commercial species and good candidate for afforestation in northeast China. It is widely planted in lead-stressed soils which can induce oxidative damage in this plant. Increasing tolerance to lead(Pb) stress is therefore of keen interest. A greenhouse experiment was conducted to identify the biomass, physiological responses and Pb accumulation of L. olgensis seedlings to Pb stress under succinic acid(SA) application and to explore the interaction of exogenous SA applications and stress resistance. L. olgensis seedlings were planted in Pb-stressed or unstressed haplic cambisols in pots. In Pb-contaminated soils the seedlings were treated daily with concentrations of SA solutions at a rate approximately equivalent to 0, 0.04,0.2, 1.0, or 2.0 mmol kg^(-1) of soil for 10, 20, and 30 days,respectively. Pb treatment induced damage in the seedlings and led to the inhibition of biomass accumulation in roots,stems and leaves, and a rise in Pb accumulation in fine roots and leaves. Malondialdehyde(MDA) content and electrolyte leakage in leaves significantly increased while peroxidase(POD) activities, soluble protein and photosynthetic pigment contents in leaves were all reduced.Physiological toxicity was promoted with increasing Pb treatment times. When Pb-stressed seedlings were exposed to SA(especially 10.0 mmol L-1 over 20 days), the physiological responses for Pb-only were reversed and the biomass of roots, stems, and leaves dramatically increased.SA facilitated Pb uptake in fine roots and leaves but more Pb accumulated in fine roots. The results demonstrate that exogenous SA alleviates Pb-induced oxidative injuries and improves the tolerance of L. olgensis seedlings to Pb stress.

STUDY ON PREDICTION MODEL OF SEED CROP OF LARIX OLGENSIS SEED ORCHARD

By taking three forecasting methods (sample trees, sample branches and climate factors prediction) the forecasting cquation of sccd wcre cstablished through correlation analysis and regrcssion analysis on seed crop of Qingshan and Qinhe Larix olgensis sced orchard. The research results showed that it gave more accurate prediction with less working load by taking pistillate numbers of four sample branches at middle layer of crown to predicate seed crop. And the short-term prediction equation of this method was cstablishcd. The correlation analysis between seed crop and climate factors showed that the relative humidity May and June, annual evaporative amount, and accumulated temperature above 10℃, possess the highest effect on bud differentiation and seed crop, then the middle-term predication equation of climate factors was established.

Nutrient retranslocation from the fine roots of Fraxinus mandshurica and Larix olgensis in northeastern China

Nutrient retranslocation in trees is important in nutrient budgets and energy flows in forest ecosystems. We investigated nutrient retranslocation in the fine roots of a Manchurian Ash(Fraxinus mandshurica) and a Larch(Larix olgensis) plantation in northeastern China. Nutrient retranslocation in the fine roots was investigated using three methods, specifically, nutrient concentration, the ratio of Ca to other elements(Ca/other elements ratio) and nutrient content. The method based on nutrient content proved most suitable when investigating nutrient retranslocation from fine roots of the two species. The nutrient-content-based method showed that there were retranslocations of N, P, K and Mg from the fine roots of Manchurian Ash, with retranslocation efficiencies of 13,25, 65, and 38 %, respectively, whereas there were no Ca retranslocations. There were retranslocations of N, P, K, Ca and Mg from the fine roots of Larch, with retranslocation efficiencies of 31, 40, 52, 23 and 25 %, respectively.

STUDY ON PHYSIOLOGICAL CHARACTERISTICS OF LARIX OLGENSIS AND FRAXINUS MANSHURICA UNDER CONTROLLED CONDITIONS

The net photosythetical rate, respiration rate, light compensation point and light saturation point of Larix olgensis and Fraxinus manshurica were measured by Model-865 Co2Infrared Analyzer under controlled conditions (in coviron phytotron). For net photosythetical rate of Larix ogensis and Fraxinus manshurica, the optimum air temperature was 25, 28℃ respectively, the optimum soil water potantial was-20, -10 kPa repectively, the optimum soil water content was 20.31%, 23.42% respectively, and the optimum air humidity was 90%. The optimum soil water potantial of respiration rate was -30 kPa. The light compensation point for the two species was 3.36, 4.8 μmol/m2s respectively and light saturation was 804, 880μmol/m2s.

Simulation of the growth ring density of Larix olgensis plantation wood with the ARMA model

Because growth ring data have temporal features, time series analysis can be used to simulate and reveal changes in the life of a tree and contribute to plantation management. In this study, the autoregressive(AR) and moving average modeling method was used to simulate the time series for growth ring density in a larch plantation with different initial planting densities. We adopted the Box–Jenkins method for the modeling, which was initially based on an intuitive analysis of sequence graphs followed by the augmented Dickey–Fuller stationarity test. The order p and q of the ARMA(p, q) model was determined based on the autocorrelation and partial correlation coefficient figure truncated on the respective order.Through the residual judgment, the model AR(2) was only fitted to the larch growth ring density series for the plantation with the 1.5 9 2.0 m^2 initial planting density.Because the residuals series for the other three series was not shown as a white noise sequence, the modeling was rerun. Larch wood from the initial planting density of2.0 9 2.0 m^2 was modeled by ARMA(2, 1), and ARMA((1, 5), 3) fitted to the 2.5 9 2.5 m^2 initial planting density,and the 3.0 9 3.0 m^2 was modeled by AR(1, 2, 5).Although the ARMA modeling can simulate the change in growth ring density, data for the different growth ring time series were described by different models. Thus, time series modeling can be suitable for growth ring data analysis, revealing the time domain and frequency domain of growth ring data.

Geographic Variation Pattern of Larix olgensis

On the basis of the data of provenance test for 10 years in the total natural rangc of Larix olgensis from10 seeds collection sitcs, the geographie variation patterns have been made by means of canonical correlation analysis; (1)The basic variation patterns of growth characters is in vertical grudual change along the elevation gradient as principal, andgradual change along the latitude as supplement. (2) The Xiaobehu provenance with low elevation and low equivalent latitude is the good gene resource center of L. olgensis It has the genetic characters of rapid growth, high stability and finetimber quality. (3) The synthetical interaction between water and heat factors is the major factor to produce the variation ofL. olgensis and the tempcrayurc is the principal one. (4) Among the genetic variations of geographic population characters,the variation of growth is the most obvious one, and it could be taken as the main character for provenance division. (5) Byallocating the secds from the low equivalent latitude region to the northem suitable afforestation areas, the greater geneticgain could be obtained.

THE OCCURRENCE AND DEVELOPMENT OF THE ADVENTITIOUS ROOTS FORMING GREEN SHOOT CUTTING OF LARIX OLGENSIS

The experiment with the green shoot cutting propagation of Larix olgensis wasmade in the Maoer Mountain Forestry Farm on July 5,1990.After the callus formed ofthe cutting base before adventitious roots came out the materials were collected from thecutting base and fixed in FAA solution.By the paraffin sections and anatomical observatio-n.the results indicted that it needed 40 days from the cutting to the rooting.The inducedprimordium of the cutting was endogenous in origin,which came from:(1)vascularcambium of the callus,and became roots;(2)meristematic cell population in the intersectbetween the cambium and xylem ray of the cutting base.There were extruding,crushingprocess and enzymolysis when the adventitious roots broke through the outer layers in tworooting types.

Bulk Method of Hardwood Cutting Propagation of Larix olgensis

Larix olgensis is a major reforestation species in areas of the northeast part of China. Rooted cutting for vegetativepropagation on this Larch has been carried out since 1990 and later the bulk method of hardwood cutting propagation alsohas bcen studied. The result is as follows: (1) Cuttings from physiologically juvenile trees are easy to root. and develop bet-ter roots. In addition. there are many methods to enhance the cuttings rooting. (2) The good time. for seedling transplantingis in the middle of August. ’Treatments with plant hormones and rare-earth compounds can improve the seedling survivalrate. and the survival rate of the seedlings soaked in chelate rare-earth molybdenum compound (300×10-6) for 3 hoursreached 94.00% 19.49% higher than that of the control. (3) Methods of maintaining juvenility such as hedging. is essentialto further developments for operational planting of vegetative propagates. Hedges in 5 years old can prodace 91 .75 shootsper tree- cxceeding the control to 1 52.2%..

THE EFFECT OF LOW TEMPERATURE ADVERSITY ON MALE FLOWERS AND POLLEN IN LARIX OLGENSIS

The electrie conductivity of pollen life-force and male flowers of Larix olgensis on condition of low temperature adversity has been respectively measured by means of fluorescent dying method and conductivity method in 1992 and 1994. The results indicate that:(1 ) If the same clonal pollen is treated at equal time at different low temperatures, there are significant differences in pollen life-force, the pollen life-force is the largest between O℃aild -3℃, in higher or lower temperature range, the pollen life-force will decrease. The measurement of electric conductivity of male flowers provcs that the low temperature of below -3℃ is the inain reason that the cell membrane is damaged and the pollen.life-force decreases. (2) The same clonal pollen life-force at the saine low temperature will gradually decrease with the increasing of frozen time. Its main reason is that suffocation and losing body fluid result in the damage of cell membrane, the measurement of electric conductivity of male flowers call prove that. (3) If pollen is treated with the same low temperature, the humidity will be the main factor of affecting pollen life-force. (4) There are significant differences in Larix olgensis’s resistance against low temperature in its different growth stage, the male flower’s resistance of near pollen spreading period is low. (5) The resistance is different within clones. (6) The resistance against low temperature of Larix call be incrcased by means of chemical treatment.

Genetic variation and superior provenances selection for wood properties of Larix olgensis at four trials

Larix olgensis,one of the most important timber species in northeastern China,is used for paper making and construction.In this study,10 wood properties(wood density,fiber length,fiber width,fiber length-to width ratio,hemicellulose content,cellulose content,holocellulose content,lignin content,ash content,and carbon content)of 10 provenances of L.olgensis planted at sites of CuoHai(CH),JiaGeDaQi(JGDQ),LiangShui(LS),and Mao'erShan(MES)were analyzed.The results of ANOVA showed that almost traits differed significantly among locations and provenances,with a significant interaction effect.Each trait also differed significant among provenances within sites.The phenotypic and genetic coefficient of variation(PCV and GCV)and provenance heritability(H 2)for wood properties ranged from 1.122 to 27.365%,from 0.564%to 21.113%and from 0.332 to 0.996,respectively.A correlation analysis showed that wood density was significantly negatively correlated with cellulose content and holocellulose content at sites CH,JGDQ,and LS,but were significantly positively correlated at site MES.Wood density was significantly negatively correlated with lignin content at CH and JGDQ,but not at LS and MES.Fiber width(FW)was negatively correlated with the ratio of fiber length(FL)to width across sites,and FW and FL/W were all positively correlated with FL.Lignin content was significantly positively correlated with hemicellulose content at site JGDQ and significantly negatively correlated with cellulose content and with holocellulose content at site MES.Interestingly,carbon content was positively correlated with cellulose content and holocellulose content at CH,but negatively correlated with these two traits at site MES.In a correlation analysis of wood properties with geographic,soil and climatic characteristics at the four sites,wood properties were mainly correlated with latitude and altitude of the site and affected by the average annual precipitation and temperature simultaneously.To select superior pulpwood provenances and high carbon storage provenances,we selected the two best provenances with excellent wood properties for each location based on a multi-trait comprehensive evaluation,which can be used as the preferred materials for the establishment of large-scale plantations in specific locations.

EFFECT OF LOW TEMPERATURE ON POLLEN VITALITY OF LARIX OLGENSIS

After the treatment of pollen of larix olgensis at the different low temperature,the pollen vitality was observed by using fluorescent staining method.several concluuons were ob-tained:1)0℃一3℃ is the best temperature range for storing pollen of Larix olgensis.2)At the same temperature,humidity is the key factor influencing the pollen vitality,3)Different clones shows different resistance to low temperature.Among the ten clones 2# clone shows the highest resistance.

Preliminary analysis of two NAC transcription factor expression patterns in Larix olgensis

The NAC transcription factor family is plant-specific with various biological functions.However,there are few studies on the NAC gene involving coniferous species.Bioinformatics research and expression analysis of NAC genes in Larix olgensis can be used to analyse the function of the NAC gene in the future.Screening of excellent genetic materials and molecular breeding have been utilized to cultivate high-quality,stress-resistant larches.According to the transcriptome data for L.olgensis,the genes Uni-gene81490 and Unigene70699 with complete ORFs(open reading frames)were obtained by conserved domain analy-sis and named LoNAC1 and LoNAC2,respectively.The cDNAs of LoNAC1 and LoNAC2 were 1971 bp and 1095 bp in length,encoding 656 and 364 amino acids,respectively.The molecular weights of the proteins encoded by the two genes were predicted to be 72.61 kDa and 41.13 kDa,and subcellular localization analysis indicated that the proteins were concentrated in the nucleus.The results of real-time quantitative PCR analysis showed that at different growth stages and in different tissues of L.olgensis,the relative expression levels of the two NAC genes were highest in the stem,and the expression differences were more obvious in non-lignified tissues.After drought,salt and alkali stress and hormone treatment,expression was induced to different degrees.The expression levels of LoNAC1 and LoNAC2 in semi-lignified L.olgensis were higher than in the other two periods(non-lignified and lignified),and expression levels significantly increased under drought and salt stress.Relative expression levels changed under hormone treatment.It is speculated that these two genes may not only be related to drought and salt stress and secondary growth but may also be induced by hormones such as abscisic acid.Overall,LoNAC1 and LoNAC2 are genetic materials that can be used for molecular breeding of larch.