Stability assessment of tree ring growth of Pinus armandii Franch in response to climate change based on slope directions at the Lubanling in the Funiu Mountains,China

Global warming will affect growth strategies and how trees will adapt.To compare the response of tree radial growth to climate warming in different slope directions,samples of Pinus armandii Franch were collected and tree-ring chronologies developed on northern and western slopes from the Lubanling in the Funiu Mountains.Correlation analyses showed that two chronologies were mainly limited by temperatures in the previous June-August and the com-bination of temperatures and moisture in the current May-July.The difference of the climate response to slopes was small but not negligible.Radial growth of the LBLO1 site on the northern slope was affected by the combined maximum and minimum temperatures,while that of the LBLO2 site was affected by maximum temperatures.With regards to moisture,radial growth of the trees on the north slope was influenced by the relative humidity in the current May-July,while on the western slope,it was affected by the relative humidity in the previous June-August,the current May-July and the precipitation in the current May-July.With the change in climate,the effects of the main limiting factors on growth on different slopes were visible to a certain extent,but the differences in response of trees on different slopes gradually decreased,which might be caused by factors such as different slope directions and the change in diurnal temperature range.These results may provide information for forest protection and ecological construction in this region,and a scientific reference for future climate reconstruction.

Stability assessment of tree ring growth of Pinus armandii Franch in response to climate change based on slope directions at the Lubanling in the Funiu Mountains,China

Global warming will affect growth strategies and how trees will adapt.To compare the response of tree radial growth to climate warming in different slope directions,samples of Pinus armandii Franch were collected and treering chronologies developed on northern and western slopes from the Lubanling in the Funiu Mountains.Correlation analyses showed that two chronologies were mainly limited by temperatures in the previous June–August and the combination of temperatures and moisture in the current May–July.The difference of the climate response to slopes was small but not negligible.Radial growth of the LBL01 site on the northern slope was affected by the combined maximum and minimum temperatures,while that of the LBL02 site was affected by maximum temperatures.With regards to moisture,radial growth of the trees on the north slope was influenced by the relative humidity in the current May–July,while on the western slope,it was affected by the relative humidity in the previous June–August,the current May–July and the precipitation in the current May–July.With the change in climate,the effects of the main limiting factors on growth on different slopes were visible to a certain extent,but the differences in response of trees on different slopes gradually decreased,which might be caused by factors such as different slope directions and the change in diurnal temperature range.These results may provide information for forest protection and ecological construction in this region,and a scientific reference for future climate reconstruction.

Effects of drought on non-structural carbohydrates and C,N,and P stoichiometric characteristics of Pinus yunnanensis seedlings

To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,light and moderate and severe drought treatments[(80±5),(65±5),(50±5),and(35±5)%of field water-holding capacity].Non-structural carbohydrates,carbon(C),nitrogen(N),and phosphorus(P)concentrations were measured in each plant component.The results show that:(1)With increasing drought,non-structural carbohydrates gradually increased in leaves,stems,and coarse roots,while gradually decreased in fine roots;(2)C concentrations of all were relatively stable under different stress levels.Phosphorous utilization of each component increased under light and moderate drought conditions,while N and P utilization efficiency of each plant component decreased under severe drought.Growth was mainly restricted by N,first decreasing and then increasing with increased drought;(3)There was a correlation between the levels of non-structural carbohydrates and C,N,and P in each component.Changes in N concentration affected the interconversion between soluble sugar and starch,which play a regulatory role in the fluctuation of the concentration of non-structural carbohydrates;and,(4)Plasticity analysis showed that P.yunnanensis seedlings responded to drought mainly by altering starch concentration,the ratio of soluble sugar to starch in leaves and stems,and further by alter-ing N and P utilization efficiencies.Overall,these results suggest that the physiological activities of all organs of P.yunnanensis seedlings are restricted under drought and that trade-offs exist between different physiological indicators and organs.Our findings are helpful in understanding non-structural carbohydrate and nutrient adaptation mechanisms under drought in P.yunnanensis seedlings.

The Identification of Phenylalanine Ammonia-Lyase(PAL)Genes from Pinus yunnanensis and an Analysis of Enzyme Activity in vitro

Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus yunnanensis.In the present study,three PAL genes were cloned and identified from P.yunnanensis seedlings for thefirst time,namely,PyPAL-1,PyPAL-2,and PyPAL-3.Our results indicated that the open-reading frames of PyPAL genes were 2184,2157,and 2385 bp.Phylogenetic tree analysis revealed that PyPALs have high homology with other known PAL genes in other plants.In vitro enzymatic analysis showed that all three PyPAL recombinant proteins could catalyze the deamination of L-phenylalanine to form trans-cinnamic acid,but only PAL1 and PAL2 can catalyze the conversion of L-tyrosine toρ-coumaric acid.Three PyPAL genes were expressed in different tissues in 1-year-old P.yunnanensis,and such genes had different expression patterns.This study lays a foundation for further understanding of the biosynthesis of secondary metabolites in P.yunnanensis.

云南松(Pinus yunnanensis)林外生菌根真菌的时空分布

2000年至2005年，调查了滇中及其附近云南松林下外生菌根真菌的生态分布，共采集、鉴定标本834号，计有27科39属211种（含变种、变型）。结果表明，红菇属（Russula）、牛肝菌属（Boletus）、乳菇属（Lactarius）、乳牛肝菌属（Suillus）、口蘑属（Tricholoma）、鸡油菌属（Cantharellus）和革菌属（Thelephora）等为云南松林下的主要外生菌根菌类群。它们的发生与分布受到气候（如：气温和降水）、植被（如：林龄、林地郁闭度和草本植被）、地形特征（如：海拔、坡向和坡度）、土壤条件（如：pH值、地表腐殖质和枯枝落叶层等）和人为干扰（比如：商业化采集、林木采伐、火烧和地表物清理）诸多因素的影响。总结为如下：（1）5a的调查结果显示，云南松外生菌根菌的分布表现出季节性变化的规律;其中以每年1、2、3月份的物种多样性为最低，雨季期间急剧增加，至中夏和秋末达到顶峰，种类最为繁多。（2）在海拔1500-2100m，云南松外生菌根菌种类随着海拔的升高而逐渐增加，至顶峰后，又呈缓慢下降趋势。海拔因素不但对其物种多样性，而且对于类群的组成也具有重要的影响。特定的类群往往发生在特定海拔范围。（3）随着云南松林龄的增加，外生菌根菌呈现由少至多的演替过程。外生菌根菌多样性随云南松林生长而逐渐增加的演替方式，可能与宿主光合作用产物、根部分泌物和土壤条件的逐渐变化有关。（4）人类干扰是云南松外生菌根菌物种多样性和类群组成的主要负影响因子。大规模的商业化采集可破坏或枯竭地下菌丝体，打破各物种之间的竞争平衡，减少孢子释放影响资源再生能力，进而直接影响到子实体的产生。外生菌根菌物种多样性的减少趋势会随林木砍伐和火烧强度的增加而加剧。地表枯枝落叶层与杂草密度也会影响子实体的产生，其中枯枝落叶层的厚度与云南松外生菌根菌子实体的发生呈负相关性，而被紫茎泽兰覆盖的云南松林地内也很少会发现相应的子实体。

Variation in seed and seedling traits and their relations to geo-climatic factors among populations in Yunnan Pine(Pinus yunnanensis)

Differences in seed germination and seedling growth among populations of Pinus yunnanensis Franch. were quantified to provide information for use in the regeneration, reforestation, and improvement of this species. Seed germination and seedling growth traits at the nursery stage were investigated at the population level. We evaluated relationships between pairs of measured traits as well as the association between measured traits and geo- climatic variables including longitude, latitude, elevation, temperature and precipitation. Seedling growth showed significant differences although a low magnitude of variation was found in the seed germination traits among the populations. Some populations with strong and stable growth （e.g., the Baoshan population） may be selected as superior seed sources for regeneration and reforestation. Germination percentage was negatively correlated with elevation, and positively with precipitation. In addition, germination index, vigor index and seedling height were positively correlated with precipitation. Seed germination index, cotyledon number and length, and seedling diameter were significantly and positively correlated with seed weight. Strong correlations between pairs of traits will be helpful in early evaluations for the selection of certain prominent traits.

滇西北玉龙雪山不同海拔云南松(Pinus yunnanensis)径向生长对气候因子的响应

云南松(Pinus yunnanensis)是重要的造林树种,在我国西南地区广泛分布。研究不同海拔云南松径向生长对气候变化的响应,有助于了解气候变化背景下云南松的敏感性和适应性。在滇西北丽江玉龙雪山不同海拔采集了云南松树木年轮样品,采用传统的树木年轮方法制作了不同海拔云南松树轮宽度标准化年表,并分析了不同海拔云南松径向生长与气候因子的相关性。结果表明:1)低海拔样点云南松具有较快的年平均生长速率。2)不同海拔云南松对气候因子的响应模式一致,树轮宽度与当年5—6月的降水量、帕尔默干旱指数(PDSI)和相对湿度呈正相关,与同期温度呈负相关。3)不同海拔的云南松径向生长对气象因子的响应程度不一样,即低海拔样点云南松树轮宽度与当年5月份的干旱指数、相对湿度、降水量相关系数较高;而高海拔样点的云南松树轮宽度与5—6月的降水、相对湿度、干旱指数的相关系数较低。研究表明春末夏初的水分条件是玉龙雪山云南松径向生长的主要限制因子,且低海拔地区云南松生长受水分限制更为严重,区域气候变暖和干旱化趋势可能对低海拔地区云南松的生长产生持续的负面效应。研究结果可为探讨气候变化下云南松的适宜分布区、以及云南松人工林的经营和可持续管理提供参考。

Selective logging enhances ecosystem multifunctionality via increase of functional diversity in a Pinus yunnanensis forest in Southwest China

Background:The impacts of selective logging on ecosystem multifunctionality(EMF)remain largely unexplored.In this study,we analyzed the response of nine variables related to four ecosystem functions(i.e.nutrient cycling,soil carbon stocks,decomposition,and wood production)to five selective logging intensities in a Pinus yunnanensisdominated forest.We included a control group with no harvest to evaluate the potential shifts in EMF of the P.yunnanensis forests.We also assessed the relationship between above-and belowground biodiversity and EMF under these different selective logging intensities.Additionally,we evaluated the effects of biotic and abiotic factors on EMF using a structural equation modeling(SEM)approach.Results:Individual ecosystem functions(EFs)all had a significant positive correlation with selective logging intensity.Different EFs showed different patterns with the increase of selective logging intensity.We found that EMF tended to increase with logging intensity,and that EMF significantly improved when the stand was harvested at least twice.Both functional diversity and soil moisture had a significant positive correlation with EMF,but soil fungal operational taxonomic units(OTUs)had a significant negative correlation with EMF.Based on SEM,we found that selective logging improved EMF mainly by increasing functional diversity.Conclusion:Our study demonstrates that selective logging is a good management technique from an EMF perspective,and thus provide us with potential guidelines to improve forest management in P.yunnanensis forests in this region.The functional diversity is maximized through reasonable selective logging measures,so as to enhance EMF.

ASTERYUNNANOSIDE A AND B，TWO NEW TRITERPENOID SAPONINS FROM ASTER YUNNANENSIS FRANCH

Two new oleanane-type triterpenoid saponins.sateryunn3noside A and B,were isolated from the roots of Aster yunnanensis Franch,and their Structures were elucidated based on spectral evidence and chemical hydrolysis. They have the same aglycone,Which has been assigned as 2a,3 .23-trihydroxyolean-12-en-28-cio acid,and the deference consisted only in 28-O-linked sugar moieties. Asteryunnanoside A is a 28-O-a-L-rhamnopyranosyl-(1-2)- -D-glucopyranoside and B is 28-O- -D-glucopyranosyl-(1 -2),-D-glucopyranoside of the corresponding aglycone.

Determination of 10 Kinds of Inorganic Elements in Paris polyphylla Smith var. yunnanensis(Franch.) Hand.-Mazz.(and Polygerm Varieties)

[Objectives] To determine the content of 10 kinds of inorganic elements(Pb,Cu,As,Cd,Hg,Zn,Fe,Mn,Sr and Cr) in samples of Paris polyphylla Smith var. yunnanensis( Franch.) Hand.-Mazz.( and polygerm varieties) produced in different areas. [Methods] The wet digestion and technique of inductively coupled plasma optical emission spectrometry( ICP-OES) were used. [Results] Under the experimental conditions,elements were not related to each other,and several kinds of elements could be measured at the same time. The content of Pb exceeding the standard only in sample S4 of P. polyphylla Smith var. yunnanensis( and polygerm varieties),Hg was not detected in all samples,and the rest heavy metals did not exceed the limit. [Conclusions] This study was expected to provide a certain reference for the development and utilization of P. polyphylla Smith var. yunnanensis( and polygerm varieties).

ASTERYUNNANOSIDE E,A NEW TRITERPENOID SAPONIN FROM ASTER YUNNANENSIS FRANCH

A new oleanane-type triterpene saponin. asteryunnanoside E. has been isolated from the roots of Astir yunnanensis Franch. and its structure elucidated as 3-O-β-D-glucopyranosyl-bayogenin-28-O-β-glucopyranoside by means of spectral data particularly 2D NMR including COSY. HETCOR, HOHAHA and ROESY techniques and chemical transformation.

Photosynthetic traits and antioxidative defense responses of Pinus yunnanensis after joint attack by bark beetles Tomicus yunnanensis and T.minor

Bark beetles Tomicus yunnanensis and T.minor are two important pests of Pinus yunnanensis and can cause massive death of pine trees.In this study,we examined several traits related to photosynthesis in P.yunnanensis and their relationship with antibiotic defense responses after joint attack by the two bark beetles at the shoot and the trunk stages.When shoots were attacked by the beetles,the abundance of chlorophylls,carotenoids,and the rates of net photosynthesis(Pn)and transpiration(E)decreased in needles,while the levels of superoxide dismutase and malondialdehyde remained unchanged in both needles and phloem.The activity of peroxidases also remained unchanged in needles,but increased in phloem.The activity of catalases increased in both needles and phloem.When trunks were attacked by the bark beetles,chlorophyll abundance,Pn,E,and antioxidative enzyme activities all declined,and the declines were more pronounced than in the attacked shoots.A decrease in protein concentrations was also observed in needles and phloem from the attacked pines.Attack on shoots by the bark beetles suppressed host defense and provided a favorable environment for larval growth and development,resulting in long-term decline of pine growth potential.The results suggest that attacks on trunks by beetles caused more severe damage to host trees than attacks on shoots.

贵州高寒山区华山松Pinus armandii Franch育苗试验

华山松是贵州高寒地区（当地）主要造林用树种,在退耕还林、还草工程和宜林荒山造林中,也是西部地区作为首选树种之一,但华山松常规育苗需要一年才能育成。本育苗试验采用＂百日苗＂育苗法可缩短育苗时间,经2009~2012年重复试验,100 d内苗高10 cm以上,地径0.2 cm以上,大大提高了综合效益,在高寒山区具有一定的实用性。

Identification of Paris polyphylla Smith var. yunnanensis(Franch.) Hand.-Mazz.(Polygerm Varieties) Produced in Gaoligong Mountain Areas

[Objectives] To make original plant and microscopic identification and study the traits of Paris polyphylla Smith var. yunnanensis( Franch.) Hand.-Mazz.( polygerm varieties) produced in Gaoligong Mountain areas,and provide experimental data for their identification and application. [Methods] The original plant powder was used,and paraffin sections and physicochemical properties were identified. [Results]P. polyphylla Smith var. yunnanensis( polygerm varieties) produced in Gaoligong Mountain areas showed obvious microscopic features and physicochemical properties. [Conclusions] This study was expected to provide certain reference for identification of original plant and medicine and formulation of quality standard for P. polyphylla Smith var. yunnanensis( polygerm varieties) produced in Gaoligong Mountain areas,and provided basis for their further research and development.

Capacitance Characteristics of Pinus densata,Pinus tabuliformis,Pinus yunnanensis and the hybrids Pinus tabuliformis×Pinus Yunnanensis

We employed capacitance to evaluate the kinship and interspecific variation of homoploid hybrid conifer Pinus densata,P.tabuliformis,P.yunnanensis and artificial hybrids of P.tabuliformis(maternal parent)and P.yunnanensis(paternal parent)which were cultivated and selected in the common garden experiment.By measuring capacitance spectra under different voltage frequencies,we could differentiate different germplasms based on the electrical response.We aims to demonstrate that P.densata as the hybrid of P.tabuliformis and P.yunnanensis based on the capacitance values of the species,and to provide new evidence to the previously known biological evidence,as well as and the parental effect on the hybrids.Our results revealed that capacitance values between the species are significantly different in the spectra where P.yunnanensis positioned at the lowest and P.densata was much higher than all other species,indicating that P.densata had possessed a great capacity to store electrical energy.The capacitance spectra of P.densata and the artificial hybrid are not similar,which rejected our hypothesis.Both of the capacitance values of P.densata and the hybrids were closer to P.tabuliformis than to P.yunnanensis,which shows that the maternal influence was stronger than the paternal influence.Correlation analysis on the relationship between capacitance and fitnessrelated characteristics showed that capacitance is negatively correlated to mortality rate,and positively correlated with second-year survival rate.High capacitance values of P.densata and some of the hybrids reveal their superior adaptability to harsh environment in the Tibet Plateau.We concluded that capacitance as a new indicator for plant fitness and evolution evidence of homoploid hybrid conifers.

Variations in electrical impedance and phase angle among seedlings of Pinus densata and parental species in Pinus tabuliformis habitat environment

Electrical impedance （El） and phase angle （PHI） parameters in AC impedance spectroscopy are important electrical parameters in the study of medical pathology. However, little is known about their application in variation and genetic relationship studies of forest trees. In order to test whether impedance parameters could be used in genetic relationship analysis among conifer species, E1 and PHI were measured in a seedling experiment test composed of Pinus tabuliformis, Pinus yunnanensis, and Pinus densata in a habitat of Pinus tabuliformis. The results showed that variations in both EI and PHI among species were sig- nificant in different electric frequencies, and the EI and PHI values measured in the two populations of P. densata were between the two parental species, P. yunnanensis and P. tabuliformis. These results show that these two impedance parameters could reflect the genetic relationship among pine species. This was the first time using the two AC impedance spectroscopy parameters to test the genetic relationship analysis between tree species, and would be a hopeful novelreference methodology for future studies in evolution and genetic variation of tree species.

云南松苗木萌枝能力对截干高度的响应

【目的】探讨截干高度对云南松苗木萌枝能力的影响,为采穗圃穗条生产和适宜截干高度的确定提供技术支撑。【方法】以1年生云南松播种苗为试验材料,采用单因素完全随机区组试验,设置截干高度(即留桩高度)5,10和15 cm 3个处理,以不截干为对照,截干后每月测定萌枝数量和萌枝生长量,年底测算萌枝保存率和母株保存率,分析不同截干高度下萌枝数量和萌枝生长量的变化进程及累积数量的变化规律,并结合萌枝和母株保存率,探讨萌枝能力对截干高度的响应规律。【结果】不同截干高度萌枝发生的进程有所差异,截干高度5 cm萌枝数量速生期开始最早(截干后15 d)、持续时间最短(22 d),而截干高度10 cm萌枝数量速生期开始最晚(截干后22 d)、持续时间最长(39 d);净萌枝数量增加集中在截干后1~2个月的速生期内,占理论极值的57.51%~58.55%;不同截干高度的净萌枝数量和累积萌枝数量在生长前期、速生期、生长后期均表现为截干高度5 cm<截干高度10 cm<截干高度15 cm;截干高度5,10和15 cm的平均单株累积萌枝数量分别为12.82,19.72和22.71枝/株,不同处理间存在显著差异(P<0.05)。不同截干高度云南松苗木的萌枝平均生长量积累过程呈现“慢-快-慢”的节律,截干高度5,10和15 cm的萌枝生长量分别为6.094,5.486和7.868 cm,处理间无显著差异(P>0.05);云南松萌枝生长量增加集中在截干处理后1~3个月,占总萌枝生长量的70%以上。截干高度5,10和15 cm的萌枝存活率分别为86.14%,76.26%和63.48%,不同处理间差异显著(P<0.05);母株保存率分别为95.83%,100%和100%,不同处理间无显著差异(P>0.05)。综合来看,截干高度5 cm的萌枝数量少,但存活率最高;截干高度10 cm的萌枝数量多,且存活率较高;截干高度15 cm的萌枝数量多,但存活率最低。【结论】截干高度10 cm的处理既利于枝条萌发和萌枝生长,又具有较高的萌枝存活率,可较好权衡萌枝数量、生长量和存活率之间的关系,因此确定其为最有利于萌枝潜力发挥的适宜留桩高度。

施肥对云南松苗木-土壤氮、磷、钾化学计量比的影响

【目的】了解外源氮、磷添加后云南松苗木各器官及土壤中氮、磷、钾化学计量比的变化特征,为云南松苗木培育过程中养分的合理管理提供依据。【方法】以2年生云南松苗木为试材,设置氮、磷配施试验,每种肥料设置3个施肥水平,氮肥的施用水平为0,0.4和0.8 g/株,磷肥的施用水平为0,0.8和1.6 g/株,共9个施肥处理组合。施肥后2,4,6个月分别测定苗木根、茎、叶及土壤的氮(N)、磷(P)、钾(K)含量,计算N∶P、N∶K、K∶P,探讨施肥对云南松苗木-土壤氮、磷、钾化学计量比的影响。【结果】施肥处理后2,4,6个月,9个施肥处理组合的云南松苗木根、茎、叶平均N∶P分别为2.85~4.30,3.60~5.12和5.18~6.65,总体上表现为氮受限,其中根的平均N∶P以氮肥0.8 g/株+磷肥0.8 g/株处理最小,茎、叶的平均N∶P以氮肥0.4 g/株+磷肥0.8 g/株处理最小;平均K∶P分别为3.72~5.87,5.04~7.26和5.62~7.71,均以氮肥0.4 g/株+磷肥0.8 g/株处理最小;平均N∶K分别为0.71~0.78,0.71~0.74和0.89~0.93,总体上均以氮肥0.4 g/株处理最大。根、叶N∶P、K∶P随苗木的生长呈现降低趋势,茎N∶P、K∶P表现为先降低后升高的趋势;根、叶N∶K随苗木的生长呈现出先降低后增加的趋势,茎N∶K呈现增加趋势。施肥后2,4,6个月各施肥处理组合土壤的平均N∶P、N∶K和K∶P分别在3.48~4.58,0.70~0.74,4.93~6.52内波动,随着时间推移,N∶P、K∶P呈现先降低后增加的趋势,N∶K呈增加趋势。氮、磷配施改变了苗木与土壤的相关关系,且这种关系存在明显的时间变异,施肥处理后2个月内云南松苗木各器官与土壤化学计量间无明显的相关关系,而随时间延长,呈显著相关关系。【结论】综合来看,氮、磷配施改变了苗木及土壤的氮、磷、钾化学计量比,表现为降低了苗木及土壤的N∶P、K∶P,提高了苗木及土壤的N∶K。随着时间变化,N∶P、K∶P总体上呈现出降低的趋势,N∶K呈现出逐渐增加的趋势,表明氮限制有加剧趋势。

不同种源云南松幼苗性状的异速生长及变异分析

为研究不同种源1~3年生云南松苗木苗高、地径生长变异以及异速生长指数,深入了解云南松苗期性状生长在种源间的变异特点与异速生长关系,对1~3年生的不同苗龄云南松苗木苗高、地径生长状况进行统计分析以及异速生长关系分析,比较了3个种源不同龄期云南松苗木性状的生长分化特点和异速生长指数。结果表明:不同苗龄云南松苗木苗高、地径生长在种源间存在极显著变异,性状的变异程度随苗龄的增长整体呈现减弱的趋势且性状间存在极显著的相关性。种源内苗高变异系数随苗龄的增长先增加后降低,整体波动范围为32%~50%,地径变异系数整体波动范围为33%~48%,随苗龄增长呈递减趋势,变异来源中种源内层次的因素随苗龄的增加而减弱。新平种源苗高生长的平均变异系数为46%,高于另外2个种源;不同种源不同苗龄云南松苗木间存在显著的异速生长现象,且异速生长指数是变化的。可见,苗高、地径都存在较为丰富的分化和变异,性状分化程度受时间影响明显。不同种源苗木的两个性状都以种源内变异为主,各种源苗木的变异程度不同,不同龄期苗木会根据自身生长状况调整生长策略以适应对资源的竞争。不同种源苗木异速生长关系在不同苗龄间存在极显著的差异,异速生长指数存在显著差异,随着苗龄的增加,各种源苗木苗高-地径异速生长关系模型从符合弹性自相似拟模型改变为几何相似性模型,符合小个体植株异速生长指数接近1的结果。异速生长指数随苗木生长而变化,受苗木自身遗传品质和对环境的适应能力等因素综合影响。

云南松苗木N、P、K元素含量间异速生长关系对N、P添加的响应

为了解云南松苗木不同器官N、P、K的分布特征,分析云南松不同器官N、P、K含量间的分配差异,进一步探讨各器官N、P、K元素间的异速生长关系。采用N、P二因素三水平的方法开展不同施肥试验,并对苗木采样测定,研究云南松苗木N、P、K元素含量间异速生长关系对N、P添加的响应。结果表明,云南松苗木对N、P、K在不同器官间具有不同的分配策略,总体K变动较小,N、P波动较大且相似,在各器官中N、K分配表现为萌条>叶>茎>根;P表现为萌条>茎>叶>根。与对照相比,单施N、P和N、P配施均对云南松苗木生长的影响产生一定差异,总体来看N、P配施更能促进苗木的养分合理分配,有效缓解单施N、P对植株的限制作用,使养分处于一个平衡状态,进而促进苗木的生长。随施肥时间的推移,各器官营养元素间的异速生长关系也随之发生变化,且各器官表现为N、P的积累速度相接近,总体表现为K的积累速度低于N、P。总体而言,随施肥时间的改变,云南松苗木各器官之间元素的异速生长轨迹发生了显著变化,形成不同的营养元素分配模式。