模拟氮沉降对色季拉山高寒草地土壤养分的影响

草地作为我国最大的陆地生态系统,对我国的生态文明建设具有不可估量的价值,在发挥生态系统服务功能等方面具有十分重要的作用。本试验以西藏林芝市巴宜区色季拉山高寒草地为研究对象,共设置对照CK、低氮LN、中氮MN和高氮HN(0、10、15、20 kg N·hm^(-2)·a^(-1))4种处理,研究0~20 cm高寒草地土壤中养分含量变化,探讨不同程度的氮沉降量对土壤养分的影响。结果表明:(1)在LN、MN到HN的模拟氮沉降过程中,土壤有机质、有机碳、碱解氮和可溶性总氮含量相比于CK处理均有显著增加,增幅在28.59%~65.27%之间,可溶性有机碳含量仅在MN下显著增加,增加了35.35%,易氧化有机碳在LN处理下抑制效果最强,达到72.92%,pH值在LN与HN添加下显著下降了15.67%和17.48%;(2)模拟氮沉降下色季拉山高寒草地土壤不同理化性质之间呈现显著相关关系。结论说明,土壤有机质和碳氮相关养分含量对模拟氮沉降均比较敏感,不同氮沉降水平下对色季拉山高寒草地养分有显著影响,且多数养分之间均有显著相关系,表明高寒草地不同养分之间存在紧密联系。

西藏光核桃果实表型性状变异分析与种质资源筛选

【目的】本研究是探究西藏野生光核桃果实表型性状种群变异规律,结合主成分分析筛选优良种质资源,探明生态因子对果实表型性状的影响,为光核桃良种选育和推广提供参考。【方法】根据西藏野生光核桃的集中分布区,兼顾种群生长海拔、气候和成熟期的差异,对5个地级市18个种群(SYD、AR、LD、JT、DB、QD、MX、LK、BM、GY、SZ、BJ、ZR、PZ、QN、BH、LZ、CN)进行实地调查采样,每个种群选取13株长势良好的光核桃,各单株间距大于50 m,每株分阴面、阳面和上、下4个方位采集成熟果实,从每方位的果实中随机选择5枚,共20枚,测量其表型性状。【结果】光核桃果实表型性状种群间和种群内均存在极显著差异;种群间表型分化系数均值为67.99%,表型变异主要来源于种群间;根据PCA分析结合利用部位果肉和果核,筛选出果实大、果核小、果肉厚、出核率低的果用型光核桃,代表种群为山南贡嘎县江塘镇、林芝米林县羌纳乡、林芝朗县朗镇;果实小、果核大、果肉薄、高出核率的核用型光核桃,代表种群有林芝察隅县古玉乡、日喀则亚东县上亚东乡、昌都芒康县曲登乡。RDA分析5个生态因子共解释56.00%的果实性状变异,仅年均温对果实性状的总体变异影响显著(P=0.049);两个特征性状果肉厚和出核率与生态因子的多元回归方程均回归显著(P<0.01),调整后判定系数分别为0.5993、0.7981。果肉厚与经度、海拔、年均降雨量呈负相关,与纬度和年均温呈正相关;出核率与经度、海拔、年均降雨量和年均温呈正相关,与纬度呈负相关;5个生态因子中经度、纬度、海拔对果肉厚和出核率的影响极显著。【结论】光核桃果实表型性状变异主要来源于种群间;根据表型性状筛选出了果用型和核用型光核桃及其代表种群,其特征性状主要受经纬度、海拔的影响。

5个梨品种在西藏林芝的引种表现及光合特性

为推进西藏林芝梨种植结构合理,对引进的红茄梨、绿宝石梨、翠冠梨、红太阳梨,玉露香梨5个品种的田间生长性状和光和特性进行测定,筛选出适合林芝栽培的梨品种。结果表明:5个梨品种的生长状况不同,其中翠冠梨的苗高、地径、新枝长在不同时期的增长量均较高,翠冠梨生长最好,而红茄梨较差;5个梨品种的净光合速率(Pn)不同,表现为:翠冠梨>绿宝石梨>红太阳梨>玉露香梨>红茄梨;5个梨品种的Pn日变化曲线均呈不对称双峰型;蒸腾速率(Tr)的日变化曲线主要呈现出单峰型和不对称双峰型,其中红茄梨、绿宝石梨和翠冠梨Tr的日变化曲线呈单峰型,红太阳梨和玉露香梨的Tr日变化曲线呈不对称双峰型;水分利用率(WUE)的日变化曲线主要呈不对称双峰型和倒S型;气孔导度(Gs)的日变化曲线较复杂,主要呈单峰型、倒S型、下降型和单谷型;胞间CO2含量(Ci)的日变化曲线主要呈单谷型和双谷型;气孔限制值(Ls)的日变化曲线主要呈单峰型和不对称双峰型。5个梨品种的生长状况和光合特性日变化不同,其中翠冠梨的生长状况和光合性能均优于其他品种,具有在西藏林芝地区大面积推广种植的潜力。

西藏林芝市6个梨品种的光合特性研究

通过比较西藏林芝市引种的南月、红香酥、晚秋黄、黄冠、黄金,华山6个品种的光合特性,为梨在西藏的引种栽培和选育提供参考。以西藏林芝市米林县引种栽培的南月、红香酥、晚秋黄、黄冠、黄金,华山6个梨品种为研究对象,测定比较光合参数(净光合速率、蒸腾速率、水分利用率、气孔导度、胞间CO2含量)变化。6个梨品种的净光合速率不同,表现为:红香酥>黄冠>黄金>晚秋黄>华山>南月。光合速率日变化曲线为红香酥、晚秋黄、黄金和华山呈单峰型,南月和黄冠的Pn日变化曲线呈双峰型,“光合午休”现象出现在12:00时,14:00时左右达到第2个峰值。不同梨品种的蒸腾速率(Tr)日变化曲线呈单峰型和不对称双峰型,气孔阻止值(SLR)日变化曲线呈单峰型和双谷型两种类型,水分利用率(WUE)呈单谷型、S型和下降型3种类型,胞间二氧化碳含量(Ci)日变化曲线呈单谷型和不对称双峰型,气孔导度(Gs)日变化曲线有多种类型。6个梨品种间光合日变化不同,各光合参数存在差异,红香酥、晚秋黄和黄冠光合性能优于其他品种,具有在西藏林芝大面积推广种植的潜力。

氮磷添加对高寒草地土壤养分和相关酶活性的影响

土壤是陆地生态系统的重要组分,其养分条件决定了植物生长状况及生产力的大小。氮和磷是植物生长的必需营养元素和主要限制因子,氮磷增加会改变土壤性质,影响土壤中的氮、磷含量,从而对土壤地上植物生长造成影响。为评估氮磷添加对草地土壤养分的影响及为高寒草地如何应对氮磷沉降提供科学依据,在藏东南色季拉山高寒草地开展氮磷添加试验,共设置对照(CK,不添加)、氮添加(N,15 kg·hm^(-2)·a^(-1))、磷添加(P,75 kg·hm^(-2)·a^(-1))、氮磷混合添加(NP:15 kg·hm^(-2)·a^(-1)N;75 kg·hm^(-2)·a^(-1)P)等4个施肥处理,施肥1年后采集土壤样品在实验室进行相关指标测定。试验结果表明,N、P和NP处理均显著促进高寒草地土壤有机碳、全氮、铵态氮、硝态氮和有效磷含量(P<0.05)。其中,NP添加对有机碳影响最大,增加了50.86%;N添加下土壤全氮、铵态氮、硝态氮和有效磷含量达到最大增幅,分别增加了59.14%、47.58%、333.85%和59.68%;NP添加下显著促进全磷含量(P<0.05),增加了19.41%,表明NP添加对土壤养分含量有积极影响,且影响较大。不同处理均显著促进蔗糖酶、葡萄糖苷酶和脲酶活性(P<0.05),N和NP添加对蔗糖酶和葡萄糖苷酶影响较大,增幅在53.08%—92.63%之间,P添加下脲酶活性增幅最大,达到140.73%。相关性分析表明,土壤有效养分与土壤酶活性之间显著相关,pH与土壤养分和酶活性呈显著相关(P<0.05)。结果表明,NP添加对土壤碳氮相关养分和酶活性影响较大,均呈现显著促进作用,且养分和酶活性之间呈现交互影响。NP添加通过提高土壤酶活性,加快土壤中大分子有机物分解,从而使土壤养分含量增加。N添加对土壤氮相关养分影响较大,表明施氮可缓解青藏高原高寒草地氮限制。

Water Holding Characteristics of Coarse Woody Debris of Abies fabri Forest on the East Slope of Tibet Sygera Mountain

Coarse woody debris( CWD) has an important role in hydrological function and water and soil conservation function of forest ecosystem especially mountain forest ecosystem. To understand water holding capacity of CWD in subalpine forest of southeast Tibet,CWD reserve of primitive A. fabri forest in Sygera Mountain was investigated by sample plot method,and water absorption and storage capacity of CWD was studied by using soaking method. The results showed that decay grade was positively related to water storage potential,that is to say,the higher the decay grade,the larger the water storage potential. Saturated water holding capacity,saturated water holding rate,effective water holding capacity and effective water holding rate of A. fabri CWD all rose with decay grade increased,and the order was Ⅴ>Ⅳ>Ⅲ>Ⅱ>Ⅰ. CWD reserve was 51.555 t/hm^2,and the maximum water storage capacity was 71.601 t/hm^2,while effective water storage capacity was 60.861 t/hm2,which was equivalent to 6.086 mm of rainfall.

西藏水果产业发展现状问题及对策建议

西藏是我国果树资源最为丰富的地区之一。通过分析西藏果园发展现状,认为西藏水果产业发展缓慢的原因包括果园管理粗放,缺乏技术指导;生产成本高,销售困难;品种结构不合理及产业化水平低等,结合西藏生产实际,提出引进技术人才,科学管理果园;政府出台优惠政策,降低生产成本;引进、培育新品种及提高水果产业化水平等建议,为西藏自治区水果产业发展提供参考。

Short-term Effects of Nitrogen Deposition on Soil Physical and Chemical Properties of Tibetan Forest-Grassland Landscape Boundary

[Objective] The paper was to study the effects of nitrogen deposition on soil nutrients and soil dissolved organic carbon in forest-grassland landscape in Linzhi, Tibet, and to provide scientific basis and basic data for understanding and assessing the effect of atmospheric nitrogen deposition on soil nutrients and soil dissolved organic carbon. [Method] From July 2014 to August 2015, in situ nitrogen deposition （CK0 kg· hm^2/a, LN25 kg·hm^2/a, MN 50 kg·hm^2/a, HN 150 kg· hm^2/a） was simulated in the forestgrassland boundary of Zhuqudeng village, Bujiu Township, LinzhiCounty, Tibet. The soil samples were collected for analyzing nutrient and dissolved contents in the soil layer of 0-20 and 20-40 cm. The effects ofdifferent nitrogen deposition levels on soil nutrients and dissolved organic carbon （DOC） were studied. [Result] Nitrogen deposition had significantimpacts on soil organic matter, total N, total P, total K, available N, available P, available K, exchangeable Ca, exchangeable Mg, pH, and DOC（P〈0.05）. （2） With the deepening of nitrogen deposition from CK, LN, MN to HN in the 0-20 cm boundary soil, the contents of organic matter, total N,total P, available P, exchangeable Ca, exchangeable Mg and DOC kept decreasing, and the content of total K and available N increased continuously. The pH increased in LN treatment and decreased in HN treatment, while the available K content was decreased in LN and HN treatment, butincreased in MN treatment. （3） The contents of organic matter, total N, total P, available N, available P, exchangeable Ca, exchangeable Mg andDOC all decreased at the soil layer of 20-40 cm under the same nitrogen deposition. The pH increased in LN treatment, but decreased in HN treatment; the content of total K decreased in LN treatment and increased in MN and HN treatments; the content of available K decreased in LN andHN treatments, but increased in MN treatment. （4） With the deepening of boundary soil layer （0-20 to 20-40 cm）, the organic matter, total N, totalP, available P, available K, exchangeable Ca, exchangeable Mg, DOC showed the same response to simulated nitrogen deposition, while the available N and total K responded differently. [Conclusion] Different levels of N deposition had certain impact on soil nutrient, and the variation of soilnutrients was not the same at different levels.

The Effect of Nitrogen Deposition on Soil Microorganisms in the Woodland-Grassland Border of Tibet

Nitrogen deposition was simulated from July 2014 to August 2015 in the grassland, woodland, and woodland-grassland border in Zhuqudeng Village, Bujiu Township, Linzhi County,(CK, 0 kg·hm^2·a^(-1); LN, 25 kg·hm^2·a^(-1), MN, 50 kg·hm^2·a^(-1); HN, 150 kg·hm^2·a^(-1)). NH_4NO_3 was used as nitrogen source to analyze the number of microorganisms in soil layers of 0–20 cm and 20–40 cm and explore the effect of different degrees of nitrogen deposition on soil microorganisms in grassland, woodland, and woodlandgrassland border. The results showed that: the number of bacteria in the grassland increased significantly under the treatment of LN, and the number of bacteria in the woodland-grassland border and woodland had a rising response under the influence of nitrogen deposition; the number of actinomycetes in the grassland increased in MN and HN treatment, and significantly increased in the border and woodland under LN treatment; the number of molds decreased sharply in the grassland, woodland, and woodland-grassland border.

基于B/S体系和MVC技术架构的纺织标准管理系统

文章为解决纺织标准存放凌乱、使用不方便、更新不及时、过期回收不彻底等问题,开发了纺织标准管理系统。该系统是基于B/S体系和MVC技术架构,采用"表现层—逻辑层—数据访问层"三层体系架构组织,MySql数据库和Apache应用服务器建成,能够实现标准分类管理、检索、上传、下载、共享、实时更新等功能。

Effect of Fallen Wood of Abies fabri Forest on Seedling Recruitment in Tibet Sygera Mountain

The impact on seedling recruitment by fallen wood of A. fabri forest in Tibet Sygera Mountain was studied. The results showed that regenerated seedlings on fallen wood roughly showed normal distribution,and there were more regenerated seedlings in the middle of fallen wood,while regenerated seedlings were fewer at two ends. Fallen wood at level IV had the most regenerated seedlings,followed by level-III fallen wood,and regenerated seedlings were the fewest on fallen wood at level V. The number and species of regenerated seedling on and around fallen wood on the west slope were more than that on the east slope. With the improvement of decomposition level,regenerated seedling per unit area firstly increased and then decreased,but the number of regenerated seedling on and around fallen wood was far more than that in woodland.

Short-term Effects of Nitrogen Deposition on Soil Enzyme Activities in Tibet Grasslands

[Objective] The paper was to study the effects of nitrogen deposition on enzyme activity in different layers of soil. [Method] With grass-land located in Zhuqudeng Village, Bujiu Township, Linzhi City, the Tibet Autonomous Region, as the object, nitrogen deposition was simulated from July 2014 to August 2015. Four N addition treatments were established： control （0 kg·hm^2/a）, low N （LN, 25kg·hm^2/a）, medium N （MN, 50 kg·hm^2/a） and High N （HN, 150 kg·hm^2/a）, aiming at measuring enzyme activity （invertase, catalase, urease, amylase, cellulase, polyphenol oxidase and β-glucosi- dase） in different layers of grassland soil （0 -20 cm and 20-40 cm）. [Result] （1） Different levels of simulated nitrogen deposition had significant impact on invertase and β-glucosidase at the soil depth of 0-20 cm （P〈0.05）, but no significant impact on catalase, urease, amylase, cellulase and polyphenol oxidase（P〉0.05）; invertase, polyphenol oxidase and β-glucosidase had significant response to nitrogen deposition at the soil depth of 20- 40 cm （P〈0.05）, while catalase, urease, amylase and cellulose had no significant response （P〉0.05）. （2） The activities of invertase and polyphenol oxidase were enhanced at the soil depth of 0-20 cm, and that of β-glucosidase was inhibited. （3） With the deepening of nitrogen deposition, the ac- tivities of invertase and cellulose were enhanced at the soil depth of 20-40 cm; the activity of polyphenol oxidase was reduced in LN treatment, but increased in HN treatment; the activity of β-glucosidase was increased in LN treatment, but decreased in MN treatment. （4） With the deepening of soil layers, invertase and polyphenol oxidase responded similarly to simulated nitrogen deposition. [Conclusion] The results provide certain scientific basis and fundamental data for better understanding and evaluating the effects of nitrogen deposition on enzyme activity in grassland soil.

The Effect of Nitrogen Deposition on Soil Enzyme Activity in the Forest Grassland Landscape Boundary of Tibet

The simulated nitrogen deposition [control check(CK), 0 kg·hm^2/a; low nitrogen(LN),25 kg·hm^2/a; medium nitrogen(MN), 50 kg·hm^2/a; high nitrogen(HN), 150 kg·hm^2/a] was performed from July 2014 to August 2015 in the forest-grassland boundary in Zhuqudeng Village, Bujiu Township,Linzhi City, Tibet Autonomous Region to analyze the activity of enzymes(invertase, catalase, urease,amylase, cellulase, polyphenol oxidase, and β-glucosidase) in soil layers of 0-20 cm and 20-40 cm and explore the effect of different levels of nitrogen deposition on enzyme activity different layers of soil.The results showed that: ① different levels of simulated nitrogen deposition had remarkable effects on sucrase, amylase, cellulase, polyphenol oxidase and β-glucosidase in the soil layer of 0-20 cm(p < 0.05) and unremarkable effects on catalase and urease(p > 0.05); in the soil layer of 20-40 cm, the response made by sucrase, catalase, urease, amylase, cellulase, polyphenol oxidase and β-glucosidase to nitrogen deposition reached a significant level(p < 0.05). ② In the soil layer of 0-20 cm, the activity of urease and poyphenol oxidase reduced under LN treatment and enhanced under HN treatment, and the activity of invertase,catalase, amylase, cellulose, and β-glucosidase was inhibited by nitrogen deposition. ③ In the soil layer of20-40 cm, the activity of polyphenol oxidase and β-glucosidase reduced under under LN treatment and enhanced under HN treatment, and the activity of invertase, catalase, urease, amylase, and cellulase was inhibited by nitrogen deposition. ④ With the deepening of the boundary soil layer(from 0-20 cm to20-40 cm), urease and β-glucosidase made different responses to the different levels of nitrogen deposition,while invertase, catalase, amylase, cellulose, and polyphenol oxidase showed the same response to nitrogen deposition.

Effects of Different Afforestation Techniques on Soil Nutrients in Populus alba Woodland

[Objective] The research aimed to study the influence of different afforestation technology measures on soil nutrients of P. alba wood-land in arid valley region of Rikaze, Tibet. It aimed to improve afforestation technology measure in arid valley region of Rikaze, Tibet, and provide theoretic basis for restoring the degraded ecosystem at upper reaches of the Yarlung Zangbo River. [ Method] In arid valley region of Duojiao Vil-lage, Nanmulin County, Rikaze City, the planted land using rooting powder, egg shell, leaves, mud and water retention agent was taken as re-search object, while the land without any afforestation measures was taken as the control, to determine soil nutrients under different afforestation measures. [Result] Under different afforestation measures, the contents of various soil nutrients were all obviously higher than control, in which available potassium, available phosphorus, alkali hydrolysable nitrogen and organic matter in soil obviously increased than control, but there was no similar rule among different measures. [Conclusion] Vegetation restoration in dry valley belt of Rikaze by different afforestation measures is favorable for improving physical-chemical properties of soil and increasing soil fertility.

四个梨品种在西藏林芝的生长表现及光合特性

以"黄金梨""红香酥""华山梨""中梨1号"4个品种为试材,对其生长参数、生理指标、叶片表型参数及光合特性进行比较分析,研究不同梨树品种在西藏林芝地区生长及光合特性,以期为梨树在西藏高原地区的适应性评价以及引种品种筛选提供参考依据。结果表明:"黄金梨"地径显著高于其它3个品种,且变异程度低;随着光合有效辐射的增加,4个品种净光合速率均先增大,达到峰值后呈下降趋势,其中"黄金梨"显著高于其它3个品种;主成分分析筛选出"黄金梨"综合评价得分最高。"黄金梨"具有较高的光合生产潜力,在西藏林芝地区高海拔、低温、强辐射等极端环境条件下生长表现及光合特性较好.