Climate-growth relationships of Pinus tabuliformis along an altitudinal gradient on Baiyunshan Mountain,Central China

A set of standard chronologies for tree-ring width(TRW),earlywood width(EWW)and latewood width(LWW)in Pinus tabuliformis Carr.along an altitudi-nal gradient(1450,1400,and 1350 m a.s.l.)on Baiyunshan Mountain,Central China to analyze the effect of varying temperature and precipitation on growth along the gradi-ent.Correlation analyses showed that at all three altitudes and the TRW and EWW chronologies generally had signifi-cant negative correlations with mean and maximum tem-peratures in the current April and May and with minimum temperatures in the prior July and August,but significant positive correlations with precipitation in the current May.Correlations were generally significantly negative between LWW chronologies and all temperatures in the prior July and August,indicating that the prior summer temperature had a strong lag effect on the growth of P.tabuliformis that increased with altitude.The correlation with the standard-ized precipitation evapotranspiration index(SPEI)confirmed that wet conditions in the current May promoted growth of TR and EW at all altitudes.Significant altitudinal differences were also found;at 1400 m,there were significant positive correlations between EWW chronologies and SPEI in the current April and significant negative correlations between LWW chronologies and SPEI in the current September,but these correlations were not significant at 1450 m.At 1350 m,there were also significant negative correlations between the TRW and the EWW chronologies and SPEI in the prior October and the current July and between LWW chronology and SPEI in the current August,but these cor-relations were not significant at 1400 m.Moving correlation results showed a stable response of EWW in relation to the SPEI in the current May at all three altitudes and of LWW to maximum temperature in the prior July-August at 1400 m from 2002 to 2018.The EWW chronology at 1400 m and the LWW chronology at 1450 m were identified as more suitable for climate reconstruction.These results provide a strong scientific basis for forest management decisions and climate reconstructions in Central China.

Effects of gibberellin A_(4/7), 6-benzylaminopurine and chlormequat chloride on the number of male and female strobili and immature cones in Chinese Pine (Pinus tabuliformis) with foliar sprays

Three kinds of plant growth regulators, gibberellinA 4/7 （GA 4/7 ）, 6-benzylaminopurine （BA）, and chlormequat chloride （CCC）, were evaluated for their ability to promote strobilus and cone production in a Chinese pine （Pinus tabuliformis Carr.） clonal seed orchard. Treatments （0, 250, 500, or 1000 mg L -1 ） were applied during three periods （June- July, July-August and August-September） in 2005. Of the three plant growth regulators, GA 4/7 was the best for promoting flower and cone production. Trees sprayed with GA 4/7 （500 mg L -1 ） from June to September had significantly more female strobili and immature cones than controls and other treatments （p≤0.0001）. The best time to apply GA 4/7 was in June. BA at 500 mg L -1 significantly increased female flower and immature cone production, compared to other treatments and controls （p≤0.0001）, while promotion of male strobili was unchanged. Chlormequat chloride at 1000 mg L -1 significantly increased the number of male strobili, compared to the other treatments （p≤0.0001）. Spraying CCC at500 mg L -1 significantly increased the number of female strobili, compared to controls （p0.05）, but it had no effect on immature cone production （p0.05）. These results are important for improving seed production and seed orchard management of Chinese pine.

Genetic variation of wood tracheid traits and their relationships with growth and wood density in clones of Pinus tabuliformis

To improve wood quality for pulpwood industries, it is important to examine not only wood density but also its components, especially tracheid characteristics. We studied genetic variations in the following tracheid traits by earlywood （EW） and latewood （LW）： tracheid length （TL）, double wall thickness （WT）, radial lumen diameter （R_D1）, tangential lumen diameter （T_D1）, radial central diameter （R_D2）, and tangential central diameter （T_D2）. We also studied the relationship with the following growth traits： diameter at breast height （DBH）, height （H）, crown breadth south-north axis （NSC）, crown breadth east-west axis （EWC）, ring width （RW）, latewood percentage （LWP）, and wood density （WD）. All sample materials were collected from a 33-year old clonal seed orchard of Pinus tabuliformis Carr. Genetic variation among clones was moderate for all tracheid traits, 9.49-26.03%. Clones significantly affected WT, R_D1, R_D2, T_D1, T_D2, and the two ratios WT/R_D1 and TL/T_D2 in EW but had no effects in LW. Clones significantly affected TL in LW but had no effects in EW. H2/C was higher in LW （0.50） than in EW （0.20） for TL, while H 2/C was higher in EW （0.27-0.46） for other tracheid traits and the two ratios （TL/T_D2 and WT/R_D1） than in EW （0.06-0.22）. WD and TL were significantly positively correlated, but WT and TL were negatively correlated both at individual and clone levels; all tracheid diameters and the four ratio values （EW_WT/ R_D1, LW WT/R_D1, EW_TL/T_D2 and LW_TL/ T_D2）, were strongly positively correlated with DBH, H, NSC, WEC and RW, and strongly negatively correlated with WD both at individual and clone levels. The most important variables for predicting WD were LW_TL, EW_WT and R_D1 in both EW and LW （r2= 0.22）. Selecting the top 10% of the clones by DBH would improve DBH growth by 12.19% （wood density was reduced by 0.14%） and produced similar responses between EW and LW for all tracheid traits： a reduction of 0.94 and 3.69% in tracheid length and increases in tracheid diameters （from 0.36 to 5.24%） and double wall thickness （0.07 and 0.87%）. The two ratios WT/R_D1 and TL/T_D2 across tissues （EW and LW） declined 0.59 and 4.56%, respectively. The decreased tracheid length and the ratio between tracheid length and diameter is disadvantageous for pulp production. The unfavorable relationship of tracheid traits with wood density indicate that multiple trait selection using optimal economic weights and optimal breeding strategies are recommended for the current longterm breeding program for P. tabuliformis.

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.

Net Primary Productivity and Management Potential of Artificial Pinus tabulaeformis Forest in Shanxi Province

The dynamic variation of net primary productivity of artificial Pinus tabulaeformis forest was studied in Shanxi Province,and potential productivity of artificial forest was predicted to provide reference for improving quality of regional forest stand. The regression equation was established by using the stratification and harvesting method with the relative growth model. Cumulative method and Thornthwaite Memorial model was used to estimate the actual and potential productivity of the forest. The productivity of P. tabulaeformis forest increased with the increase of age and started decrease with the mature period. The actual productivity of P. tabulaeformis forest was 4. 462 t/( ha·year); the contribution rate of trees was 72. 17% of the total productivity,and with the increase of age,the total biomass increased but productivity decreased at late near-mature forest; the contribution rate of herb layer was 21. 16% in the young forest stage,and then decreased gradually. On the contrary,the contribution rate of shrub layer increased gradually,and the contribution rate of the grassland was more than that of the herb layer,so as the key period of structural management; the average potential productivity of forest was 8. 422 t/( ha·year),and the potential space of P. tabulaeformis was at least 32% in Shanxi Province. In conclusion,the potential space of productivity of P. tabulaeformis was at least 32%,and the primary limiting factor of P. tabulaeformis forest productivity in Shanxi Province was rainfall.

Sap flow characteristics and physiological adjustments of two dominant tree species in pure and mixed plantations in the semi-arid Loess Plateau of China

It is essential to understand the water consumption characteristics and physiological adjustments of tree species under drought conditions,as well as the effects of pure and mixed plantations on these characteristics in semi-arid regions.In this study,the normalized sap flow(SFn),leaf water potential,stomatal conductance(gs),and photosynthetic rate(Pr)were monitored for two dominant species,i.e.,Pinus tabuliformis and Hippophae rhamnoides,in both pure and mixed plantations in a semi-arid region of Chinese Loess Plateau.A threshold-delay model showed that the lower rainfall thresholds(RL)for P.tabuliformis and H.rhamnoides in pure plantations were 9.6 and 11.0 mm,respectively,and the time lags(τ)after rainfall were 1.15 and 1.76 d for corresponding species,respectively.The results indicated that P.tabuliformis was more sensitive to rainfall pulse than H.rhamnoides.In addition,strong stomatal control allowed P.tabuliformis to experience low gsand Prin response to drought,while maintaining a high midday leaf water potential(Ψm).However,H.rhamnoides maintained high gsand Prat a lowΨmexpense.Therefore,P.tabuliformis and H.rhamnoides can be considered as isohydric and anisohydric species,respectively.In mixed plantation,the values of RLfor P.tabuliformis and H.rhamnoides were 6.5 and 8.9 mm,respectively;and the values ofτwere 0.86 and 1.61 d for corresponding species,respectively,which implied that mixed afforestation enhanced the rainfall pulse sensitivity for both two species,especially for P.tabuliformis.In addition,mixed afforestation significantly reduced SFn,gs,and Prfor P.tabuliformis(P<0.05),while maintaining a high leaf water potential status.However,no significant effect of mixed afforestation of H.rhamnoides was observed at the expense of leaf water potential status in response to drought.Although inconsistent physiological responses were adopted by these species,the altered water consumption characteristics,especially for P.tabuliformis indicated that the mixed afforestation requires further investigation.

Transcriptomic and proteomic analyses of far-red light effects in inducing shoot elongation in the presence or absence of paclobutrazol in Chinese pine

In angiosperms, low red (R)/far-red (FR) ratio light increases gibberellin (GA) levels. GA signaling in conifer seedlings requires FR to promote shoot elongation and reduce the inhibition of shoot elongation induced by paclobutrazol (PAC), yet the effects of far-red light in inducing shoot elongation in the presence or absence of PAC is poorly understood. In this study, transcriptomic and proteomic analyses was used to examine the molecular mechanism of FR regulation of shoot elongation in Chinese pine (Pinus tabuliformis Carr.) seedlings in the presence of PAC. Four treatments were compared: white light + water (WW), FR + water (RW), white light + PAC (WP), and FR + PAC (RP), and 1436 differentially expressed genes (DEGs) and 450 differentially expressed proteins (DEPs) were identified in RW_WW (RW contrast WW), and 1862 DEGs and 481 DEPs in RP_WP (RP contrast WP). Metabolic and signal transduction pathway analyses of DEGs and DEPs in RW_WW and RP_WP, indicated that the former required more energy than the latter. Moreover, gibberellic acid, auxin, and brassinolide are equally important in RW_WW and RP_WP for shoot elongation, except for the ethylene pathway. Amino acid metabolism and cell wall organization were significantly enriched in RW_WW and RP_WP, respectively. In summary, RW_WW and RP_WP had different effects in secondary metabolism, energy metabolism, amino acid metabolism, cell wall organization, and hormone response. These results provide an important theoretical and reference basis for studying the regulatory effect of low R/FR and PAC in conifer shoot elongation.

黑皮油松外植体的抗褐化处理与诱导培养

黑皮油松在组织培养过程中存在明显的褐化现象,严重影响离体培养的诱导效果。为有效地抑制黑皮油松组培中外植体的褐化,本试验以黑皮油松休眠叶芽为外植体,研究聚乙烯吡咯烷酮(polyvinyl pyrrolidone, PVP)、活性炭(active carbon, AC)、维生素C (vitamin C, VC)三种不同抗褐化剂对黑皮油松休眠芽外植体褐化与萌发的影响。结果表明,添加3种抗褐化剂对黑皮油松外植体褐化有不同程度的抑制效果,抗褐化剂处理的外植体褐化程度相比对照明显减轻,在培养8 d时抗褐化剂处理开始表现出抑制外植体褐化的作用,大部分处理外植体褐化率在培养至24 d时达到峰值,随后趋于稳定。整体来看,PVP处理的防褐化效果优于AC和VC处理,添加1 500 mg/L PVP抑制黑皮油松外植体褐化的效果最佳,褐化率仅为25.56%,比对照低51.11%,该处理的休眠芽萌发率也最高(37.78%),说明添加PVP不仅有效抑制黑皮油松外植体的褐化,也明显促进黑皮油松休眠芽的萌发启动。本研究为黑皮油松组织培养过程中褐变这一瓶颈问题的解决提供理论依据和技术支撑。

鞍山地区造林密度对林木生长的影响研究

本文以抚顺地区30 a油松(Pinus tabuliformis)人工林为研究对象,测定了不同栽植密度对林木胸径、冠幅、树高、枝下高以及生物量等相关林木生长参数的影响,研究结果表明:胸径和冠幅随着林分密度的增加而逐渐减少;树高和高径比随着林分密度增大而呈现先降低后升高的趋势;枝下高随林分密度的增大而递增;枝下高与树高比则随密度增加而先增加后趋稳定;单株总生物量随林分密度的增大而呈现"先减小后增加再减少"的趋势。

辽宁省油松种子园营建关键技术

从油松(Pinus tabuliformis Carr.)种子园的规划设计、建园技术、经营管理技术3方面对油松种子园营建关键技术进行了归纳和总结,以期为辽宁省科学化、规范化、标准化营建油松种子园提供理论依据。为人工油松林分的营建提供可靠稳定的优良种质,实现区域生态公益林与用材林建设质量的稳定提高,同时推进辽宁省森林生态系统与林业经济的建设和发展。

油松异砧嫁接培育红松果材林

在辽宁省锦州等地以油松(Pinus tabuliformis)为砧木,红松为接穗,进行异砧嫁接红松试验。对各试验地红松、油松物候特征,异砧嫁接初期情况及嫁接后15 a生长情况进行调查与分析。结果表明:红松与油松在几个主要物候指标中具备一定的匹配性。异砧嫁接成活率在70%以上,保存率在60%以上。异砧嫁接红松林分生长、结实均好于未嫁接红松。