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Journal of forestry Research 2017年第5期28卷 975-982页

作者： Huiying Cai Xueying Di Guangze Jin Center for Ecological Research Northeast Forestry University school of forestry Northeast Forestry University

Convenient and effective methods to determine seasonal changes in individual leaf area (LA) and leaf mass (LM) of plants are useful in research on plant physiology and forest ecology. However, practical methods for estimating LA and LM of elm (Ulmus japonica) leaves in different periods have rarely been reported. We collected sample elm leaves in June, July and September. Then, we developed allometric models relating LA, LM and leaf parameters, such as leaf length (L) and width (W) or the product of L and W (LW). Our objective was to find optimal allometric models for conveniently and effectively estimating LA and LM of elm leaves in different periods. LA and LM were significantly correlated with leaf parameters (P < 0.05), and allometric models with LW as an independent variable were best for estimating LA and LM in each period. A linear model was separately developed to predict LA of elm leaves in June, July and September, and it yielded high accuracies of 93, 96 and 96%, respectively. Similarly, a specific allometric model for predicting LM was developed separately in three periods, and the optimal model form in both June and July was a power model, but the linear model was optimal for September. The accuracies of the allometric models in predicting LM were 88, 83 and 84% for June, July and September, respectively. The error caused by ignoring seasonal variation of allometric models in predicting LA and LM in the three periods were 1-4 and 16-59%, respectively.

关键词： Leaf length Leaf width Linear model Power model Non-destructive method

Differences of carbon and nitrogen stoichiometry between different habitats in two natural Korean pine forests in Northeast China's mountainous areas

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Journal of Mountain Science 2022年第5期19卷 1324-1335页

作者： WANG Ya-fei DUAN Wen-biao QU Mei-xue CHEN Li-xin LAN Hang-yu YANG Xi-feng MENG Si-jing CHEN Jia school of forestry Northeast Forestry UniversityHarbin 150040China

There is a strong link between vegetation and environmental ***,to elucidate how the stoichiometric characteristics of plants respond to different habitats,we studied organic carbon(C)and total nitrogen(N)stoichiometry characteristics of plants in four different habitats of two different natural Korean pine *** of the habitats(gaps,mounds,and pits)were formed via tree uprooting,whereas an undisturbed site(closed canopies)was used as a *** followings were our main findings:(1)the organic carbon content of more than half of the 12 picked plants showed significant differences in different *** of the plants in pit-mound complexes exhibited lower organic carbon contents than plants in gaps and closed canopies;(2)there was no significant differences in the total nitrogen content in 13 of the 25 groups of plant samples;(3)interestingly,the C/N of the sample groups with significant differences in total nitrogen also showed significant differences;(4)there was no significant variations in the stoichiometric characteristics of plants that grew in gaps;however,the variations among plants that grew in pits and mounds were significant;(5)through redundancy analysis(RDA),we find that the main factors effecting the C and N stoichiometric characters of the plants were plants own regulation and the change of photosynthetically active radiation(PAR).In conclusion,the C and N stoichiometric characteristics of plants did not respond to gap formations,but they did strongly respond to pit-mound complex *** active radiation was the most important effective factor to plants in the four habitats.

关键词： Uprooting Site type Carbon Nitrogen Stoichiometric characteristics

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

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Journal of forestry Research 2018年第6期29卷 1497-1505页

作者： Jinfeng Song Hongguang Zhang Chengwei Duan Xiaoyang Cui school of forestry Northeast Forestry University Maoershan Forest Research Station Northeast Forestry University

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-1of 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 *** 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 *** 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.

关键词： Soil Pb stress Succinic acid Larix olgensis Physiological response Pb uptake

M^2 factor of four-petal Gaussian beam

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Chinese Physics B 2008年第10期17卷 3708-3712页

作者：周国泉樊艳 school of Sciences Zhejiang Forestry University

Based on the second-order moments, this paper derives an analytical expression of the M^2 factor of four-petal Gaussian beam. The results show that the M^2 factor is only determined by the beam order n. The corresponding numerical calculations are also given. As the beam order increases, the augment of M^2 factor is disciplinary. As the expression of M^2 factor is expressed in series form and becomes more complicated, a new concise formula of M^2 factor is also presented by using curve fitting of numerical calculations. When 3 ≤ n ≤ 200, the maximum error rate of fitting formula will not exceed 2.6% and the average error rate is 0.28%. This research is helpful to the applications of four-petal Gaussian beam.

关键词： beam propagation four-petal Gaussian beam second-order moment

Composition of Airy disc

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Chinese Optics Letters 2008年第6期6卷 395-397页

作者：周国泉储修祥郑军 school of Sciences Zhejiang Forestry University

The description of a plane wave diffracted by a circular aperture is directly started from the Maxwell＇s equations. Based on the vector angular spectrum representation of Maxwell＇s equations, the diffracted plane wave is decomposed into the TE and TM terms. The analytical TE and TM terms in the far field are presented by stationary phase. As the TE and TM terms are orthogonal to each other in the far field, their sum constitutes the so-called Airy disc pattern. Therefore, this research reveals the composition of Airv disc. which is beneficial to deepen and enhance the recognition of the classical diffraction problem.

关键词： Chromatographic analysis Communication channels (information theory) Elastic waves Storage allocation (computer)

Stem radial CO_2 conductance affects stem respiratory CO_2 fluxes in ash and birch trees

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Journal of forestry Research 2019年第1期30卷 21-29页

作者： Xiuwei Wang Zijun Mao M.A.McGuire R.O.Teskey school of forestry Northeast Forestry University Key Laboratory of Forest Plant Ecology of Ministry of Education Northeast Forestry University Warnell school of forestry and Natural Resources University of Georgia

The CO_2 released from respiring cells in woody tissues of trees can contribute to one of three fluxes:efflux to the atmosphere(E_A),internal xylem sap transport flux(F_T),and storage flux(DS).Adding those fluxes together provides an estimate of actual stem respiration(R_S).We know that the relative proportion of CO_2 in those fluxes varies greatly among tree species,but we do not yet have a clear understanding of the causes for this *** possible explanation is that species differ in stem radial CO_2 conductance(g_c).A high g_c would favor the E_A pathway and a low g_cwould favor the F_***,g_chas only been measured once in situ and only in a single tree *** measured g_cusing two methods in stems of Fraxinus mandshurica Rupr.(ash)and Betula platyphylla Suk.(birch)trees in situ,along with R_S,E_A,F_T and *** radial CO_2 conductance was substantially greater in ash trees than in birch *** to that finding,in ash trees over 24 h,E_Aconstituted the entire flux of respired CO_2 ,and F_Twas negative,indicating that additional CO_2 ,probably transported from the root system via the xylem,was also diffusing into the *** ash trees,F_T was negative over the entire 24 h,and this study represents the first time that has been *** addition of xylem-transported CO_2 to E_A caused E_Ato be 9% higher than the actual R_Sover the diel measurement *** trees,which had lower g_c,also had a more commonly seen pattern,with E_A accounting for about 80% of the CO_2 released from local cell respiration and F_T accounting for the *** inorganic carbon concentration in xylem sap was also lower in ash trees than in birch trees:2.7 versus 5.3 mmol L^(-1),*** results indicate that stem CO_2 conductance could be a very useful measurement to help explain differences among species in the proportion of respired CO_2 that remains in the xylem or diffuses into the atmosphere.

关键词： Stem CO2 conductance Stem respiration Stem CO2 efflux Transport flux Stem temperature Sap flow Sap flux density

The Wigner distribution function of a super Lorentz–Gauss SLG_(11) beam through a paraxial ABCD optical system

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Chinese Physics B 2013年第10期22卷 272-280页

作者：周益民周国泉 school of Sciences Zhejiang Agriculture & Forestry University

An orthonormal beam family of super Lorentz-Gauss （SLG） beam model is proposed to describe the higher-order mode beams with high divergence, which are generated by a high power diode laser. Here we consider the simplest case of the SLG beams, where there are four mutually orthogonal SLG beams, namely SLG00, SLG01, SLG10, and SLGll beams. The SLG00 beam is just the Lorentz-Gauss beam. Based on the Collins integral formula and the Hermite-Gaussian expansion of a Lorentz function, an analytical expression for the Wigner distribution function （WDF） of an SLG11 beam through a paraxial ABCD optical system is derived. The properties of the WDF of an SLG11 beam propagating in free space are demonstrated. The normalized WDFs of an SLG11 beam at the different spatial points are depicted in several observation planes. The influence of the beam parameter on the WDF of an SLGI 1 beam in free space is analyzed at different propagation distances. The second-order moments of the WDF of an SLG11 beam in free space are also examined. This research reveals the propagation properties of an SLGll beam from another perspective. The WDFs of SLG01 and SLG10 beams can be easily obtained by using the WDFs of Lorentz-Gauss beam and the SLG11 beam.

关键词： Wigner distribution function super Lorentz-Gauss beam paraxial ABCD optical system

Spatiotemporal self-similar solutions for the nonautonomous (3+1)-dimensional cubic-quintic Gross-Pitaevskii equation

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Chinese Physics B 2012年第3期21卷 145-150页

作者：戴朝卿陈瑞品王悦悦 school of Sciences Zhejiang Agricultural and Forestry University

With the help of similarity transformation, we obtain analytical spatiotemporal self-similar solutions of the nonautonomous （3＋1）-dimensional cubic-quintic Gross-Pitaevskii equation with time-dependent diffraction, nonlinearity, harmonic potential and gain or loss when two constraints are satisfied. These constraints between the system parameters hint that self-similar solutions form and transmit stably without the distortion of shape based on the exact balance between the diffraction, nonlinearity and the gain/loss. Based on these analytical results, we investigate the dynamic behaviours in a periodic distributed amplification system.

关键词： Gross-Pitaevskii equation similarity transformation self-similar solutions

Soil pore identification with the adaptive fuzzy C-means method based on computed tomography images

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Journal of forestry Research 2019年第3期30卷 1043-1052页

作者： Yue Zhao Qiaoling Han Yandong Zhao Jinhao Liu school of Technology Beijing Forestry University

The complex geometry and topology of soil is widely recognised as the key driver in many ecological processes. X-ray computed tomography (CT) provides insight into the internal structure of soil pores automatically and accurately. Until recently, there have not been methods to identify soil pore structures. This has restricted the development of soil science, particularly regarding pore geometry and spatial distribution. Through the adoption of the fuzzy clustering theory and the establishment of pore identification rules, a novel pore identification method is described to extract pore structures from CT soil images. The robustness of the adaptive fuzzy C-means method (AFCM), the adaptive threshold method, and Image-Pro Plus tools were compared on soil specimens under different conditions, such as frozen, saturated, and dry situations. The results demonstrate that the AFCM method is suitable for identifying pore clusters, especially tiny pores, under various soil conditions. The method would provide an optional technique for the study of soil micromorphology.

关键词： CT soil images Fuzzy C-means Fuzzy clustering theory Pore identification rule

Effects of KNO_3 pretreatment and temperature on seed germination of Sorbus pohuashanensis

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Journal of forestry Research 2013年第2期24卷 309-316页

作者： BIAN Lei YANG Ling WANG Jian-an SHEN Hai-long school of forestry Northeast Forestry University State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University)

We characterized the effects of KNO3 pretreatment and germination temperature on dormancy breaking and germination of mature mountain ash seeds. Seeds treated with KNO3 and germinated at 25 ℃ followed by 5 ℃ had significantly higher germination percentages and germination potentials （51% and 49%, respectively）, compared with controls. These treated seeds also exhibited reduced germination initiation times （minimum of 48 days）, and elevated germination rate indices （up to 97）. The germination of seeds subjected to long-term cold storage （2 years at 0-5 ℃） was also significantly improved by 3 days of 4% KNO3 pretreatment before germinating under a variable temperature regimen （5 ℃ followed by 25 ℃, and followed by 5 ℃）. Germination percentages and germination potentials for these cold-stored seeds reached 67% and 54%, respectively, and the germination rate index increased to 126.99. Pretreatment of mountain ash seeds with KNO3 represents a practical, effective, and pollution-free method for improving germination, and can be implemented easily within a variety of nursery settings.

关键词： Sorbus pohuashanesis seed dormancy seed germination KNO3 pretreatment