美国柔枝松研究现状及其应用前景

文章主要阐述了柔枝松在美国的研究现状及其在我国引进应用的前景.柔枝松(Pinus flexilis James.)又名五针松、落基山白松,是北美洲西部分布最广泛的松属树种之一.其生境干旱,能够耐干旱、耐寒和耐瘠薄,能适应多种土壤,还能抗强风,适应性很强,也是先锋树种.柔枝松早期苗木生长缓慢,但具优良的生物学特性,遗传多样性较高,不同种源、家系(包括无性系)的柔枝松在树冠特征、根系分布、树高及胸径生长、抗逆性(耐寒、耐旱、耐瘠薄等)等方面都有很大的差异.该树种也是一种经济价值较高、具有开发前景的优良树种.因此,在我国北方地区,特别是在西北及华北地区引种柔枝松,具有非常广阔的应用前景.     

柔枝松引种试验初报

为了掌握柔枝松在中国的生长适应情况,对柔枝松引种后1 a生苗木的生长情况进行了研究,并选择乡土树种油松、华山松和白皮松作为对照。结果表明,柔枝松种源1和种源2的场圃发芽率分别为24.25%和25.25%,均低于油松(36.5%),但高于白皮松(18.25%)和华山松(13.25%);成活率比乡土树种低;柔枝松的苗高生长较慢,柔枝松种源1和种源2的1 a生苗苗高分别为3.1 cm?和3.6 cm?,低于油松(6.3 cm)、华山松(5.2 cm)、白皮松(4.3 cm);柔枝松种源1和种源2的1 a生地径,分别为0.175 cm?和0.178 cm,低于油松(0.208 cm)但与华山松(0.182 cm),与白皮松(0.178 cm)相差不大;柔枝松种源1和2主根平均长度分别达到了19.1 cm1、4.8 cm,均长于乡土树种,两个柔枝松种源之间相比,种源2优于种源1。     

黑龙江省西部地区柔枝松播种育苗技术

对柔枝松的原产地和播种区气候进行了简述;对柔枝松播种的关键技术,特别在种子处理时,提出不用层积处理,只在种子一端剪开一小口的方法;同时对播种方法和抚育管理也进行了阐述。     

柔枝松组培苗不定根形成的影响因子探讨

试验以组织培养获得的柔枝松不定芽为对象,对其进行不定根诱导研究。结果发现：IBA对不定根的诱导无明显影响。IBA和NAA配合使用时,形成了大量畸形不定根。NAA对不定芽的伸长生长有明显的促进作用,当培养基中添加0．05mg·L^-1NAA时,苗高达3．12cm,显著高于其他处理。不同浓度NAA及其不同诱导时间对不定根的形成无明显促进作用,反而促进了大量愈伤组织的形成。总之,柔枝松不定芽在无植物生长调节剂的1／2GD培养基能稳定诱导不定根形成,最高生根率为16．67％,说明柔枝松不定芽可能易诱导潜伏根原基,并在无植物生长调节剂的刺激的培养条件下伸长生长。IBA和NAA的使用浓度和诱导时间仍需进一步研究。     

不同种源柔枝松组织培养苗移栽后的成活率及生长情况比较

对5种不同种源柔枝松经过组织培养后获得组培苗,之后选取长势良好的健壮组培苗100株进行炼苗并移栽,分别在移栽1、3、5个月后对苗木成活率及苗木生长情况进行调查。综合以上调查结果得出:柔枝松1成活率较高、苗高最高、地径最大、主根最长、侧根数量最多,为适应性最强的种源。     

萌芽松优良种源选择的研究

萌芽松优良种源选择的研究陈永庆，代世高（四川省林业科学研究院）萌芽松（Ｐｉｎｕｓｅｃｈｉｎａｔａ）又名短叶松，原产北美，分布于北纬３０°３６＇～３９°４２＇，西经７９°００＇～９５°１８＇。因生长迅速，枝叶细小、适宜密植，我国亚热带地区已广泛引种栽植...     

全球气候变化研究的新技术--稳定碳同位素分析的应用

文中主要从植被动态研究、植物水分利用效率研究、树木年轮的δ^13C值对环境变化预测的研究以及利用^13C标记应用于碳循环的研究几方面,阐述了稳定碳同位素分析在全球气候变化研究中的应用。     

加勒比松变种及种源选择的研究*

两次多点试验表明，加勒比松种内变种间非着极为显著的生长差异，变种与环境之间呈明显的交互作用，在雷州半岛，巴哈马变种和古巴变种生长快，抗逆性强，而洪都拉期变种易受松梢螟及叶枯病危害，表现出很大的不稳定性，在海南岛，巴哈马变种和洪都拉期变种生长较快，古巴变种的生长速度则明显降低。在变种内，巴马变种以巴哈马Abaco岛的天然种源和澳大利亚昆士兰Byfield的次生种源生长最好，我国湛江的次生种源和巴哈马Andros岛的天然种源生长最差。洪都拉斯变种除了LosLimones和SantaClara的种源外，其它均生和好。古巴变种内种源间未表现出明显的生长差异。     

稳定碳同位素在森林植物水分利用效率研究中的应用

介绍了植物水分利用效率与稳定碳同位素的相关性,以及影响植物碳同位素丰度值δ13C的主要因子,重点分析几种重要环境因子对林木δ13C的影响,表明降雨量、土壤水分状况、温度、光照和CO₂浓度等因素都会在不同程度上影响植物叶片气孔导度和CO₂的固定,导致植物δ13C发生变化;并从森林抚育间伐措施对δ13C的影响,水分胁迫条件下δ13C的变化,以及δ13C的替代测定方法等方面提出了研究展望。     

稳定同位素技术在森林生态系统碳水循环中的应用

碳水循环是森林生态系统养分循环的重要组成部分,稳定同位素技术因其准确、安全、灵敏等特点被广泛应用于生态、环境、林业等众多研究领域,已逐步成为了解森林生态系统养分循环的强有力工具.近年来,稳定同位素技术在构建森林生态系统碳水耦合模型、计算水分利用效率、量化植被蒸腾和土壤蒸发对森林蒸散量的贡献等方面研究较多.通过论述森林生...     

水分胁迫对3个不同种源柔枝松种子萌发的影响

用不同浓度PEG-6000的Hoagland溶液模拟水分胁迫条件,通过萌发率、幼苗鲜重、活力指数、抗旱指数4个指标对来自美国的3个柔枝松种源种子的发芽特性进行研究,并运用隶属函数法对其进行综合评价。研究结果表明:(1)随着干旱胁迫程度的加剧,3个柔枝松种源的萌发率、幼苗鲜重、活力指数、抗旱指数都出现了不同程度的下降。且亚利桑那州种源下降的幅度最大。(2)亚利桑那州种源在发芽期的抗旱性好于另外两个种源。3个种源的综合评价值从大到小依次分别为:亚利桑那州0.561;犹他州0.380;内华达州0.132。(3)低浓度的PEG-6000的Hoagland溶液对亚利桑那州和犹他州种源的柔枝松发芽生长具有一定的促进作用。     

Changes in whole-tree water relations during ontogeny of Pinus flexilis and Pinus ponderosa in a high-elevation meadow

We measured sap flux in Pinus ponderosa Laws. and Pinus flexilis James trees in a high-elevation meadow in northern Arizona that has been invaded by conifers over the last 150 years. Sap flux and environmental data were collected from July 1 to September 1, 2000, and used to estimate leaf specific transpiration rate (El), canopy conductance (Gc) and whole-plant hydraulic conductance (Kh). Leaf area to sapwood area ratio (LA/SA) increased with increasing tree size in P. flexilis, but decreased with increasing tree size in P. ponderosa. Both Gc and Kh decreased with increasing tree size in P. flexilis, and showed no clear trends with tree size in P. ponderosa. For both species, Gc was lower in the summer dry season than in the summer rainy season, but El did not change between wet and dry summer seasons. Midday water potential (Psi(mid)) did not change across seasons for either species, whereas predawn water potential (Psi(pre)) tracked variation in soil water content across seasons. Pinus flexilis showed greater stomatal response to vapor pressure deficit (VPD) and maintained higher Psi(mid) than P. ponderosa. Both species showed greater sensitivity to VPD at high photosynthetically active radiation (PAR; > 2500 micromol m-2 s-1) than at low PAR (< 2500 micromol m-2 s-1). We conclude that the direction of change in Gc and Kh with increasing tree size differed between co-occurring Pinus species, and was influenced by changes in LA/SA. Whole-tree water use and El were similar between wet and dry summer seasons, possibly because of tight stomatal control over water loss.     

Summer precipitation influences the stable oxygen and carbon isotopic composition of tree-ring cellulose in Pinus ponderosa

The carbon and oxygen isotopic composition of tree-ring cellulose was examined in ponderosa pine (Pinus ponderosa Dougl.) trees in the western USA to study seasonal patterns of precipitation inputs. Two sites (California and Oregon) had minimal summer rainfall inputs, whereas a third site (Arizona) received as much as 70% of its annual precipitation during the summer months (North American monsoon). For the Arizona site, both the delta(18)O and delta(13)C values of latewood cellulose increased as the fraction of annual precipitation occurring in the summer (July through September) increased. There were no trends in latewood cellulose delta(18)O with the absolute amount of summer rain at any site. The delta(13)C composition of latewood cellulose declined with increasing total water year precipitation for all sites. Years with below-average total precipitation tended to have a higher proportion of their annual water inputs during the summer months. Relative humidity was negatively correlated with latewood cellulose delta(13)C at all sites. Trees at the Arizona site produced latewood cellulose that was significantly more enriched in (18)O compared with trees at the Oregon or California site, implying a greater reliance on an (18)O-enriched water source. Thus, tree-ring records of cellulose delta(18)O and delta(13)C may provide useful proxy information about seasonal precipitation inputs and the variability and intensity of the North American monsoon.     

思茅松热处理木材的研究

热处理对于提高木材的尺寸稳定性和耐久性、抵抗生物破坏等性能来说是一种非常有效的方法。作者采用油浴法对思茅松木材进行热处理工艺的探讨,分别对热处理木材的失重率、吸湿率、线性胀缩率、以及微观构造等进行了分析,研究结果表明：（1）思茅松热处理材随着处理温度和处理时间的增加,失重率逐渐增加;（2）思茅松热处理材随着处理温度和处理时间的增加,吸湿率逐渐降低;（3）思茅松热处理材随着处理温度和处理时间的增加,线性胀缩率逐渐降低;（4）在微观构造观察方面,由于早材腔大壁薄,材质较松软,经过热处理后早材部分容易引起径向开裂,早材管胞形态的变形程度要比晚材要大,早材轴向管胞壁的弯曲变形较晚材的要严重。随着热处理温度升高,热处理时间的延长,炭化程度越来越严重,为不使木材物理力学以及微观构造方面遭到严重破坏,建议木材热处理温度为160℃、热处理时间为6～12h或木材热处理温度为180℃、热处理时间为6～8h为宜。     

Ecophysiological variation in two provenances of Pinus flexilis seedlings across an elevation gradient from forest to alpine

Climate change is predicted to cause upward shifts in forest tree distributions, which will require seedling recruitment beyond current forest boundaries. However, predicting the likelihood of successful plant establishment beyond current species' ranges under changing climate is complicated by the interaction of genetic and environmental controls on seedling establishment. To determine how genetics and climate may interact to affect seedling establishment, we transplanted recently germinated seedlings from high- and low-elevation provenances (HI and LO, respectively) of Pinus flexilis in common gardens arrayed along an elevation and canopy gradient from subalpine forest into the alpine zone and examined differences in physiology and morphology between provenances and among sites. Plant dry mass, projected leaf area and shoot:root ratios were 12-40% greater in LO compared with HI seedlings at each elevation. There were no significant changes in these variables among sites except for decreased dry mass of LO seedlings in the alpine site. Photosynthesis, carbon balance (photosynthesis/respiration) and conductance increased >2× with elevation for both provenances, and were 35-77% greater in LO seedlings compared with HI seedlings. There were no differences in dark-adapted chlorophyll fluorescence (Fv/Fm) among sites or between provenances. Our results suggest that for P. flexilis seedlings, provenances selected for above-ground growth may outperform those selected for stress resistance in the absence of harsh climatic conditions, even well above the species' range limits in the alpine zone. This indicates that forest genetics may be important to understanding and managing species' range adjustments due to climate change.     

樟子松造林技术的研究

文章从生产实践出发,依据多年樟子松造林的经验,建立起一套完整的造林措施和技术环节,为樟子松造林的推广奠定了基础。     

火炬松施肥效应的研究

1992年开始实施的火炬松幼林施肥试验，4年的试验结果表明：火炬松幼林施肥效果显著，南方大部分地区土壤缺磷，宜提倡施磷，单施磷肥（50kg／hm2、100kg／hm2、200kg／hm2），4年生树高增益21．6％-28．0％。地径增益31．5％-39．8％，肥效指数为2．1-2．42；在施磷的基础上配合施氮，肥效更好，最佳的施肥组合及配比是每公顷100kgN、100kgP2O5，或者每公顷100kgN、100kgP2O5、100kgK2O配合施用，四年生树高可达3．26-3．33m，树高增益30．4％-33．2％，胸径可达5．61-5．82cm，胸径增益50．8％-56．5％。