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1.
紫竹( Phyllostachys nigra)和灰金竹( Ph.nigra var. henonis)是重要的观赏竹种,为丰富西藏的城市绿化树种种类,在拉萨市开展了紫竹和灰金竹引种栽培试验。试验采用3因素(基质、复合肥和生根粉)3水平的正交试验设计,分析不同因素和水平对引种竹种生长的影响。结果表明:引种自云南昆明的紫竹和灰金竹在西藏拉萨栽植2年后,2个竹种的成活率分别达到68.0%和47.0%,发笋率分别为36.8%和35.8%,显示出紫竹在拉萨的适应性要强于灰金竹;在各因素中,复合肥对于紫竹成活率影响最大,而生根粉对灰金竹成活率影响最大。各因素对于2个竹种生长指标影响程度的排序是一致的,即基质>生根粉浓度>复合肥施肥量;3因素最优水平组合均为:以牛粪为基质、复合肥施用量为10 g/丛、用0.02%的生根粉溶液浸泡竹篼。研究结果为紫竹和灰金竹在西藏拉萨市等高寒地区的引种及苗木繁育提供了重要的技术依据。 相似文献
2.
The occurrence of Scots pine ( Pinus sylvestris L.) seedlings and saplings (<2.0 m in height and suppressed by grazing) and ground characteristics were recorded in a 300 ha block of natural pine forest in 1993. The density of red deer ( Cervus elaphus L.) was then reduced by exclosure to approximately 3–4 deer km −2, which is below the threshold at which pine regeneration should occur. Numbers and performance of pine seedlings and saplings were further monitored 2 and 4 years after exclosure. Numbers of young pine increased over time. In the three years with observations 97–99% of pine seedlings and saplings were recorded within 20 m of a seed source. Stepwise multiple regression was used to explore the relationships of pine establishment with plot characteristics for (a) all observation plots ( n = 178) and (b) plots within 20 m of a seed source ( n = 154). The factors most closely related to the number of pine seedlings and saplings in 1997 were, for (a), seed–source distance, vegetation height, blaeberry cover, slope and deer pellet-group density in 1993, all but the last having negative effects. For (b), vegetation height, blaeberry cover and slope were again selected predictors, and again had negative effects. Possible mechanisms by which the selected main effects may influence pine regeneration are discussed, the positive relationship to deer density being considered to reflect the creation of gaps in the sward suitable for germination. However, the amounts of variation explained in the models were low, being 16% for (a) and 13% for (b), reflecting the patchy nature and diverse age of the regeneration. 相似文献
3.
马尾松在我国南方亚热带地区广泛种植,是我国主要植树造林树种之一,长期以来产生了巨大的生态和经济效益,在我国林业中有着重要地位。在全球气候变暖这一大背景下,研究马尾松森林生态系统的生物量和生产力具有非常重要的意义。文中从传统方法和遥感技术2个方面介绍了马尾松生物量和生产力的测算方法,分析了林龄、混交造林、立地条件、气候因素和林分密度对马尾松生物量和生产力的影响,并针对目前存在的问题提出未来研究的发展方向,以期为我国马尾松林的可持续经营提供参考。 相似文献
4.
The objective of this study was to analyze soil surface disturbances resulting from logging tractors, of different types (skidder and forwarder), used for clear-cutting in natural Aleppo pine forests and their consequences on plant species and functional group diversity. Results indicate that shallow disturbances (litter left in place or removed) were more frequent than deep disturbances (topsoil removed, subsoil exposed, rut exposed) regardless of the logging tractor used. The forests with previously cultivated terraces were the least disturbed. Moreover, with the aid of a functional group analysis we distinguished four plant species response groups to soil surface disturbance types. The mosaic created by these groups after clear-cutting and log removal probably contributes to a rapid auto-regeneration of a mixed plant community similar to that existing just prior to the clear-cutting. 相似文献
5.
目的 通过对马尾松接种松材线虫,分析接种前后松脂化学组分的变化,为马尾松抗松材线虫病的研究提供理论基础。 方法 以浙江省临海市5年生马尾松无性系为研究对象,提取接种前和接种松材线虫1、7、15 d的不同砧木(马尾松砧木和湿地松砧木)、不同抗性(高抗和易感)马尾松的松脂组分,分析各松脂组分含量及动态变化;利用松脂内所得有效萜类对松材线虫实施外源处理,测定松材线虫存活率。 结果 从不同砧木(马尾松砧木和湿地松砧木)、不同抗性(高抗和易感)马尾松中检出19种主要化学组分,其中,α-蒎烯、β-蒎烯、水芹烯、海松酸、山达海松酸、长叶松酸/左旋海松酸、去氢枞酸、枞酸和新枞酸含量较高。接种松材线虫1 d时马尾松砧木中β-月桂烯含量显著高于湿地松砧木(p<0.05);接种松材线虫7 d与15 d时上述组分含量在不同砧木间无显著差异。不同抗性马尾松中α-蒎烯、β-蒎烯、β-月桂烯、柠檬烯、龙脑、长叶烯、α-石竹烯、反式-β-金合欢烯和新枞酸含量在接种松材线虫后变化规律不同,接种松材线虫1 d时高抗马尾松中α-蒎烯和β-蒎烯含量显著高于易感马尾松;接种松材线虫7 d时高抗马尾松中α-蒎烯、β-蒎烯、柠檬烯和长叶烯含量显著高于易感马尾松(p<0.05);接种松材线虫15 d时高抗马尾松中α-蒎烯、β-蒎烯、柠檬烯和长叶烯含量显著高于易感马尾松(p<0.05)。对上述萜类组分进行梯度浓度松材线虫外源试验:以150 mg·g−1浓度α-蒎烯溶液处理0.5 h时,松材线虫存活率达20%;不同浓度β-蒎烯溶液对松材线虫抑制作用相同,1.20 mg·g−1浓度处理0.5 h时松材线虫存活率达50%左右;以10 mg·g−1浓度柠檬烯溶液处理0.5 h时,松材线虫存活率趋于零;以10 mg·g−1浓度长叶烯溶液处理0.5 h时,松材线虫存活率达18%。 结论 不同砧木对马尾松抗性无明显作用;接种松材线虫后,α-蒎烯、β-蒎烯、柠檬烯和长叶烯含量存在显著差异,且均为高抗马尾松显著高于易感马尾松。α-蒎烯、β-蒎烯、柠檬烯和长叶烯低浓度下抑制松材线虫活性,与马尾松抗性有关。 相似文献
6.
The long-term nature of forest crop rotations makes it difficult to determine impacts of forestry on soil nutrients that might be depleted by forest growth. We used small scale, highly stocked plots to compress the length of the rotation and rapidly induce nutrient depletion. In the study, two species ( Pinus radiata D. Don and Cupressus lusitanica Miller) are compared under two disturbance regimes (soil undisturbed and compacted), and two fertiliser treatments (nil and plus fertiliser), applied in factorial combination at 33 sites, covering the range of climatic and edaphic variation found in plantation forests across New Zealand. To assess our ability to rapidly highlight important soil properties, foliar nutrient concentrations were determined 20 months after planting. It was hypothesised that the densely planted plots, even at a young age, would create sufficient pressure on nutrient resources to allow development of relationships between properties used as indicies of soil nutrient availability and foliar nutrient concentrations. For both species significant relationships between foliar nutrients and 0–10 cm layer soil properties from unfertilised plots were evident for N (total and mineralisable N) and P (total, acid extractable, organic, Bray-2 and Olsen P). With the exception of Ca in C. lusitanica, foliar K, Ca and Mg were correlated with their respective soil exchangeable cation measures. The results thus confirm the utility of the experimental approach and the relevance of the measured soil properties for forest productivity. In unfertilised plots foliar N and P concentrations in P. radiata exceeded those in C. lusitanica, the differences being eliminated by fertiliser application. Foliar N/P ratios in P. radiata also exceeded those in C. lusitanica. In contrast to N and P, foliar K, Ca and Mg concentrations were all higher in C. lusitanica, the difference being particularly marked for Ca and Mg. P. radiata contained substantially higher concentrations of the metals Zn, Mn and Al than C. lusitanica, whereas the latter contained higher B concentrations. Possible reasons for differences between species in foliar nutrient concentrations are discussed. 相似文献
7.
为探究计划烧除对云南松林土壤水文特征的影响,为计划烧除后森林生态系统服务功能评价提供依据,以云南省新平县实施多年计划烧除的云南松纯林为研究对象,设立20 m×20 m计划烧除样地和不进行计划烧除的自然对照样地各3块。2019年2月实施计划烧除作业,进行样地调查、火烧强度和枯落物储量调查,2020年6月采集土样,测定土壤物理、化学性质和土壤入渗性能。结果表明,计划烧除后土壤容重增加且在0~10 cm土层差异显著;毛管孔隙度和总孔隙度减少但差异不显著;有机质减少并在0~20 cm土层差异显著。计划烧除后土壤自然含水率、饱和持水率、毛管持水率和田间持水量减少但差异不显著;吸湿水量减少并且在0~20 cm土层差异显著。计划烧除后土壤初渗速率、土壤平均入渗速率和土壤稳定入渗率减少;土壤初渗速率和平均入渗速率在不同样地0~20 cm土层差异显著。计划烧除对土壤稳定入渗率的显著影响因素为土壤容重、孔隙度、有机质和饱和持水率。说明计划烧除后云南松林土壤持水性能下降,入渗性能下降,对于入渗性能的影响主要是源于土壤理化性质的改变。 相似文献
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【目的】研究马尾松松脂化学组分在家系间的变异以及松脂组分间的相关性,为以松脂品质为目标的马尾松遗传改良工作提供理论依据和指导。【方法】以福建省国有来舟林业试验场11年生马尾松高产脂半同胞家系测定林为研究对象,通过气相色谱/质谱联用技术(GC/MS)检测每株样木树干胸径部位木质部内松脂化学组分的种类和含量,分析这些组分在家系间的遗传变异以及它们之间的遗传相关性,并利用在家系间差异显著的松脂化学组分对所有家系进行聚类。【结果】从马尾松松脂中共检出20种主要化学组分,其中,α-蒎烯、β-蒎烯、长叶烯、β-石竹烯、海松酸、山达海松酸、长叶松酸/左旋海松酸、脱氢枞酸、枞酸和新枞酸为松脂中含量较高的组分。经方差分析发现:单萜中的莰烯和柠檬烯,倍半萜中的长叶环烯、洒剔烯、β-石竹烯和α-石竹烯以及二萜中的海松酸和新枞酸在家系间的差异显著或极显著,家系遗传力为0.45 0.59,意味着通过家系选择,这10个组分的遗传改良可取得较好的成效。对松脂化学组分进行遗传相关分析发现:在单萜类内,β-蒎烯、莰烯和柠檬烯间遗传相关显著或极显著,组分间遗传相关系数为0.59 0.78;在倍半萜内,长叶蒎烯、长叶环烯、洒剔烯和长叶烯之间遗传相关达极显著水平,遗传相关系数为0.67 1.00,β-石竹烯和α-石竹烯遗传相关性也达极显著水平;但在二萜类内和各萜类间,遗传相关性较弱,未达到显著水平。依据在家系间差异显著的10个松脂化学组分将所有家系聚为3类。【结论】马尾松树干木质部松脂共检出20种组分,其中,莰烯、柠檬烯、长叶环烯、洒剔烯、β-石竹烯、α-石竹烯、海松酸和新枞酸受家系影响较大,受中度遗传控制。在单萜、倍半萜类和双萜类内和类间,较强的遗传相关主要出现在单萜和倍半萜类内。 相似文献
9.
目的 森林在减缓温室气体浓度和气候变化方面发挥着巨大作用,研究不同密度下林分生产力及其对气候的响应有助于森林生态系统的功能评估及适应性管理。 方法 本研究利用树木年轮学方法得到了呼伦贝尔沙地不同密度(用林分胸高断面积表示)的天然樟子松林净初级生产力,并结合气象因子分析其对温度、降水及干旱指数的响应。 结果 表明:胸高断面积为8.83、21.94、24.28、32.36和34.9 m2·hm−2的樟子松林的多年平均净初级生产力分别为1.17、2.99、3.55、4.69和4.86 t ·hm−2 ·a−1,随样地密度增加而增加;高密度樟子松林净初级生产力与上年7月和当年9月平均气温及平均最高气温显著正相关(P<0.05);5月降水是天然樟子松林净初级生产力的关键限制因子,所有密度林分的净初级生产力均与当年5月降水显著正相关(P<0.05);自上年11月至当年7月,净初级生产力与帕默尔干旱胁迫指数(PDSI)的相关系数随林分密度增加而减小,表明林分竞争的增加导致了净初级生产力对PDSI敏感性的降低。 结论 林分密度对呼伦贝尔沙地天然樟子松的净初级生产力及其气候响应存在明显影响,密度调整可能是气候变化下森林适应性管理的关键措施。 相似文献
10.
目的 研究3个试验点5年生马尾松生长和抽梢性状的家系遗传变异和遗传稳定性,为马尾松各栽植区选择优良材料提供科学依据。 方法 对2014 年营建于湖北京山、湖南桂阳、广东信宜的5年生马尾松家系区域试验林进行生长及抽梢性状调查,分析各性状遗传变异规律及相关性,在此基础上评价家系的稳定性和速生性。 结果 5年生马尾松生长和抽梢性状在家系间、地点间和家系与地点互作间均存在极显著差异。3个试验点各性状的家系遗传力均大于单株遗传力,胸径、树高、轮盘总数和抽梢性状具有较高的遗传力,家系遗传力为0.72~0.96,单株遗传力为0.45~0.88。性状相关分析表明,速生的家系抽梢次数更多,当年抽梢较长,而第1次抽梢长度较短;采用AMMI模型根据家系树高和胸径的稳定性分析得出:ZP325、ZP386家系的树高稳定性最好,ZJ5153、ZJ39家系的胸径稳定性最好,GD8家系的胸径和树高稳定性均最差。以高出各试验点树高和胸径5.00%,且高于各试验点相应的1代种子园对照为速生性评价标准,在湖北京山、湖南桂阳、广东信宜分别评价出13、4和7个速生家系,其中,GLN2和GD7家系在3个试验点既速生又稳定,可作为3地点速生、稳定型优良家系。 结论 5年生马尾松生长和抽梢性状在家系间存在丰富的遗传变异,生长和抽梢性状受到较强遗传控制;速生家系抽梢次数较多,抽梢长度较长,但固定生长量较短;GLN2和GD7家系为3地点速生、稳定型优良家系。 相似文献
11.
The development of heartwood and sapwood in maritime pine ( Pinus pinaster Ait.) in relation with tree and cambial age and growth rate was studied in ten trees randomly sampled at harvest (54–85-year-old) in a commercial stand in central Portugal. Average ring width at stem base was 1.84 ± 0.34 mm for 50 years of age. Growth rate decreased with cambial age and for the same cambial age increased along the stem with tree height. The number of heartwood rings was strongly correlated with cambial age. Heartwood formation was estimated to start at approximately 21 years of age and to proceed at a constant annual rate that increased with age (0.5 and 0.7 rings year−1 below and above 50 years of age). Within the tree, heartwood decreased with stem height, but in the lower part of the stem two patterns of variation were shown: a continuous decrease or an increase from stem base to a maximum at 2–3 m and a decrease afterwards. Sapwood radial width remained approximately constant within the tree and correlated positively with tree growth. 相似文献
12.
马尾松容器育苗菌根化促进了苗木生长,苗高比非菌根化的提高109.7%,地径提高66.4%,干物重提高411.2%;改善了容器基质的理化性质,使其结构疏松良好,水分涵养能力增强,提高了有机质、N、P、K等养分含量;促使微生物总量和细菌、放线菌、真菌比例的变化,R/S比值减小。 相似文献
13.
[目的]为认识马尾松细根对土壤养分库的贡献,[方法]本研究以三峡库区秭归县九岭头林场马尾松为研究对象,采用埋袋法进行细根分解实验,探讨0.5 mm、0.5 1 mm和1 2 mm细根的分解动态和养分释放(C、N、P、K、Ca、Mg)。[结果]结果表明:(1)细根分解368 d后,0.5 mm、0.5 1 mm和1 2 mm细根干重残留率分别为66.0%、72.0%和74.33%,且细根分解速率随直径增加而减小;(2)细根分解速率与土壤温度呈显著正相关关系(p0.05),与土壤湿度呈正相关关系(p0.05);(3)细根C、K和Mg元素迁移模式表现为释放,Ca元素表现为富集;(4)细根N、P元素在不同径级细根中迁移模式不同,0.5 mm细根N、P元素表现为释放,0.5 2 mm细根N、P元素在分解过程中出现富集阶段。[结论]马尾松细根分解与土壤温度和直径大小显著相关,其中分解与温度呈正相关,与直径呈负相关;在细根分解过程中,马尾松细根不同直径大小的不同养分元素的表现状态不一致,或富集,或释放。 相似文献
14.
目的 分析马尾松林不同演替阶段负荷量的变化特征,确定影响地表可燃物负荷量的关键因子。 方法 以武夷山国家公园中不同龄级马尾松纯林为研究对象,采用空间替代时间方法,分析马尾松林演替发展中不同类型地表可燃物的负荷量特征及其与地形、林分、气象等影响因子的关系。 结果 显示:(1)随着马尾松林的演替,地表活可燃物负荷量呈递减趋势,地表死可燃物和地表总可燃物负荷量则呈递增趋势;且总可燃物负荷量主要是由于1 h时滞细小可燃物的负荷量构成。(2)演替初期形成的马尾松幼龄林和后期的成熟林差异最为明显,至演替后期活地表可燃物下降了47.21%;死地表可燃物增加了113%。(3)RDA排序结果表明地形因子中的海拔、坡位,林分因子中的平均枝下高、平均胸径、郁闭度及气象因子中的空气温度与地表可燃物负荷量关系密切。(4)线性回归分析发现影响不同类型地表可燃物的环境因子不尽相同;平均胸径对灌木负荷量影响最大;坡位对草本、1 h时滞负荷量影响最大;平均枝下高对10 h时滞和总可燃物负荷量影响最大。 结论 不同演替阶段的马尾松林地表可燃物的负荷量不同,不同类型地表可燃物的影响因子不同。 相似文献
15.
根据浙江省21个县290块样本的优势解析木和平均解析木数据,以修正的Richards函数为数学模型,用Marquardt迭代法求出优势高,平均高和平均胸径生长曲线的拟合议程,从在则编制出多形地位指数表和多形林分生长过程表,拟合方程中引入一系列形状系数,因此对该省不同地区、不同生长条件下具有不同线形的马尾松生长曲线,有较发拟俣效果。 相似文献
16.
We investigated how multiple-crop forestry has influenced the magnitude and variability of soil and plant phosphorus (P) fertility and site disturbance. Kinleith Forest, on Mamaku Plateau, covers >100,000 ha and comprises mainly plantation Pinus radiata. Three study areas in the forest were chosen to represent natural state (native forest), first crop of P. radiata (24 years growth), and second crop of P. radiata (4 years growth of second crop). The adjacent areas have similar relief and climate, and the soils are all the same age, being predominantly Andic Haplohumods developed in 1770 calendar-year-old non-welded tephra (Taupo Ignimbrite, ca. 0.5–0.8 m in thickness) and overlying a buried paleosol on earlier tephric material. Soil properties were compared using a random geometric sampling scheme stratified in a 40-m grid. Soil samples (0–20 cm) were taken at 1.5, 4.5 and 13 m spatial intervals in random directions away from each primary node, providing 192 sample sites for each study area. Additionally at selected sites, samples of the current year's foliage from the upper crowns were collected, the thickness of Taupo Ignimbrite (i.e. depth to buried paleosol) was recorded by augering, and site disturbance was assessed using a new six-point scale based on change relative to a modal soil profile. Geostatistics and geographical information systems (GIS) were used to assess variability and effects of forest management on the measured properties. Soil Bray-2 P concentrations were below guidelines for satisfactory growth (12 mg kg−1) at all sites, and no differences were recorded between the different management areas. However, the amount of within-site variability in Bray-2 P increased with the number of crops. Foliar P concentrations were only marginally deficient in both the first and second crops, indicating that P is currently not significantly limiting growth. The lack of difference in foliar P between first and second crops indicates no crop-to-crop decline in foliar P status and suggests that no site P fertility decline has occurred. The soils have an unusual ability to continue releasing P through successive sequential extractions in the Bray-2 P test, indicating a strong buffering capacity, and this may explain the apparent lack of deficiency even with Bray-2 P values of <12 mg kg−1. The site disturbance index increased and the spatial distribution of P data became increasingly variable with crop rotation. GIS, inverse-distance weighting and kriging proved useful in illustrating the trends between crops. The spatial variability of results indicated that there was no obvious pattern to the variability and that more site-specific forest management in the region would be difficult. However, there was some evidence that less disturbance during harvesting may minimise variability of soil P supply. 相似文献
17.
为更好进行云南松苗木培育,提升云南松苗木质量,通过对2年生云南松苗木生长性状及不同部位氮(N)、磷(P)、钾(K)储量进行统计以及相关性、异速生长分析,研究云南松氮、磷、钾储量。结果表明,云南松幼苗生长2年后,其地下部位氮、磷、钾分配大小依次为钾储量>氮储量>磷储量;氮、磷、钾在土壤中的分配比例为氮储量>磷储量>钾储量;地上部位氮、磷、钾储量占单株氮、磷、钾储量的比例为钾储量>磷储量>氮储量;磷和钾在地下部位的累积速率大于地上部位的累积速率。以期为云南松苗木培育提供理论参考,为实际生产提供一定理论依据。 相似文献
18.
The aim of the present study was to evaluate the initial effects of the application of mixed wood-bark ash (MWBA) on growth and nutritional status of a Pinus radiata plantation, and on the dynamics of some of the nutrients. A field experiment, which included four treatments and four replicates in a completely random design, was established on an acidic, mineral soil rich in organic matter. The treatments were two different doses of ash (5 and 10 t ha −1), a soluble NPK fertilizer 8:24:16 (N:P 2O 5:K 2O, 200 g per plant) and an unfertilized control. The MWBA was incorporated into the soil after cutting and chopping the existing shrub vegetation and before planting. Application of the ash produced an increase in soil pH, and in the availability of P, Ca, Mg and K. The effects on soil pH and available Ca and Mg persisted for five growing seasons. The prolonged response in this study may be attributable to the effect of ash incorporation, which may have enhanced the solubility of wood ash compounds, despite the partly combusted material present in the ash. The ash improved the nutritional status, mainly in terms of Ca and Mg, and the vector analysis indicated that these elements were limiting forest production. The soluble NPK fertilizer did not produce any improvement in growth relative to the control. The concentrations of heavy metals in both soil and plant tissue were always low and did not increase significantly after application of the wood-bark ash. The positive effect of ash application on height and diameter growth was significant after 5 years, with similar results for both doses of ash. The improvement was attributed to the increases in Ca and Mg in soil.The differences between the treatments with ash and the control were much greater when the values of biomass per unit area were considered, due to the accumulative effect of a lower mortality and the enhanced growth in basal diameter and height. 相似文献
19.
[目的]了解马尾松干旱胁迫转录组序列的功能分布和SSR位点分布特征,并探索与干旱关联的SSR位点。[方法]对马尾松幼苗进行持续干旱胁迫,选取干旱10、15、25 d及正常供水对照的马尾松针叶样品,通过总RNA提取、Illumina测序、raw reads去冗、Trinity拼接获得unigenes。利用Blast比对,对Unigene序列进行GO、KOG、KEGG功能注释及分类;利用Misa软件进行SSR位点批量搜寻,primer 3. 0软件进行规模化SSR引物设计;利用GOSeq(1. 10. 0)、KOBAS(v2. 0. 12)软件对差异表达的含SSR位点Unigene进行GO、KEGG显著性富集分析。[结果]马尾松转录组194 821个Unigene中,101 806个Unigene获得注释,包含64 943个GO功能注释、35 880个KOG功能注释及30 882个KEGG注释。搜寻到6 728个SSR位点,分布于6 367个Unigene中,SSR出现频率为3. 45%;重复类型以单、三、二核苷酸为主,分别占总SSR的35. 82%、33. 03%和25. 22%;重复基序以A/T、AT/AT、AG/CT、AGC/CTG、AAG/CTT为主;基序长度以10 20 bp的短序列SSR为主;基序重复次数以5~10次重复占优势;批量设计13 338对SSR引物。422个含SSR位点Unigene具有差异表达; KEGG富集分析发现,有11个含SSR位点的差异Unigene参与了光合作用、植物激素信号传导及类胡萝卜素合成等3个与干旱响应相关的代谢途径。[结论]从较高质量的马尾松转录组中获得101 806个具有注释的Unigene;从6 367个Unigene中挖掘出6 728个SSR位点; 422个含SSR位点的差异表达Unigene中筛选出11个与干旱关联的SSR功能位点,为抗旱功能基因定位及马尾松抗旱分子机制研究奠定基础。 相似文献
20.
The low nutrient availability of the acidic and sandy soils of Galicia (Northwest Spain) is probably the main environmental factor limiting forest primary productivity in the area. These particular edaphic conditions could have imposed selective pressures on maritime pine populations leading to specific local adaptations.We first assessed the nutritional status of 22 young contemporary Pinus pinaster plantations in Northwest Spain, and then analysed the response to fertilization in three family × fertilization trials, and how this response varied across sites and genotypes.Growth of P. pinaster in Northwest Spain appeared to be largely limited by nutrient availability, where most of the plantations showed severe nutrient deficiencies, especially in P and Mg. According to these deficiencies, a strong positive response to nutrient additions was observed in the three trials, with height increments of up to 30% compared with the unfertilized control. However, the response to fertilizers was very variable from site to site, and in some cases did not agree with the foliar nutritional diagnosis. The response to fertilization was also significantly affected by pine genotype, suggesting that the plastic response to nutrient additions within each environment was under genetic control. However, the family response to nutrient availability was not consistent across sites, and no significant differences among families were observed for the RDPI plasticity index – a single index that summarizes the phenotypic change in multiple environments – when analysed across environments.The strong environmental component modulating phenotypic responses to fertilization could impose an important obstacle to evolve specific adaptations to the local edaphic conditions, as well as to artificially select genotypes adapted to different environments and silviculture regimes. 相似文献
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