张家川水池流域北京杨沙棘混交林调查研究

在立地条件、林龄基本相同的北京杨纯材及北京杨、沙棘混交林设立标准地，组成样本分别对胸径、树高、生物量进行测定，比较两种类型的树木生长量及生物量。结果表明：混交林中6年生北京杨胸径、树高平均连年生长量比纯林高1倍多，材积是纯林的5．11倍，生物量是纯林的18．98倍。为在流域内营造水保林，尤其是在营造混交林种设计方面具有一定的指导意义。     

宁南黄土区典型林分林下草本植被根系分布特征

以宁南黄土区彭阳中庄小流域4种典型林分(山杏林、山桃林、山杏柠条林、山杏沙棘林)林下草本植被为研究对象,通过采用样方-根钻法和Win RHIZO根系分析系统对不同林地0～30 cm土层的草本根系生物量和分布特征进行了定量分析,以期揭示宁南黄土区不同人工林下草本根系分布特征,为研究区生态恢复和林分配置提供参考依据。结果表明：各林地草本总生物量、总根长密度和总根系表面积密度均表现出山杏柠条和山杏沙棘混交林较大,山杏林和山桃林较小且相差不大。根系参数主要分布于0～10 cm,随着土壤深度的增加各指标均呈现递减的趋势。0～30 cm土层不同径级的根长密度和根表面积密度基本以0～0.5 mm径级的根系分布最广,0～2 mm径级的细根所占比例较大,且随着根系直径的增加二者基本呈现下降趋势。不同土层不同径级的根长密度基本表现为0～0.5 mm>0.5～1 mm>1～2 mm>2～3.5 mm>3.5 mm。总体反映出混交林林下草本植被各根系参数相较于纯林在土壤表层占比均较高,能够有效改善表层土壤结构,提高土壤抗侵蚀性能。     

宁南山区不同植被类型土壤水分变化特征

以宁夏南部山区山杏林、沙棘林、山杏×沙棘混交林3种典型植被为试材,采用野外定位监测法,对3种植被0～100 cm不同深度土壤水分进行连续1年定位观测,研究了不同植被类型土壤水分时间变化和垂直变化规律,以期了解宁南山区主要植被类型的土壤水分状况及耗水特性。结果表明：不同植被类型土壤储水量在年内变化趋势整体呈“M”型,土壤储水量按照从大到小的排序为山杏林(158.35 mm)>山杏×沙棘混交林(139.72 mm)>沙棘林(123.24 mm)。不同植被类型日平均土壤含水量的变化动态相似,其变化趋势与降雨量密切相关,9月山杏林、沙棘林、山杏×沙棘混交林地的土壤含水量分别是8月的1.56、1.41、1.49倍;3种植被类型平均土壤含水量最大值均在10月,最小值均在8月。在垂直方向上,3种植被土壤水分的变化有一定的差异性,随着土层深度的增加,沙棘林土壤含水量呈先增加后降低的趋势,山杏林、山杏×沙棘混交林土壤含水量呈波形变化趋势;3种植被类型土壤水分的变异系数总体呈下降趋势,沙棘林各土层变异系数的均值最大,为39.36%。综上,山杏林土壤水分状况最好,其次是山杏×沙棘林,为该区域植被...     

杉木枫香混交造林效果研究

本文结合杉木纯林与枫香纯林的造林效果,对杉木与枫香比例为8:1的杉木枫香混交造林的效果与优势性展开分析,结果表明,依托杉木枫香混交造林,杉木以及枫香的成活率与保存率维持在更高水平;杉木与枫香的生长效果更为理想,达到增高林分生产力的效果;混交林具备的光能利用率保持在更大状态,混交组合质量水平理想.     

水曲柳与红松混交造林技术的研究

林冠下水曲柳与红松栽植的混交林生长效果显著,不但促进水曲柳生长,而且对红松生长有利。纯林与红松、水曲柳混交林相比,蓄积量分别提高20.3%,73.2%;无论与单层纯林,还是复层混交林相比,群落较稳定,林木高生长,单株生长材积处于上升阶段,增加了土壤表层的孔隙度、持水量和通气度。     

落叶松皆伐迹地更新红松调查分析

对落叶松皆伐迹地更新红松林龄25a林分进行调查与分析,结果表明,红松保存率为45%,红松纯林已演化成红松——胡桃楸混交林;坡位对树高影响显著,坡中位、坡下位红松、胡桃楸的树高生长量分别大于坡上位红松、胡桃楸的树高生长量,坡位对胸径生长影响不显著。     

氮素供应对露地胡萝卜生长及其氮素利用的影响

研究在氮素供应水平对露地胡萝卜的产量、养分吸收和氮素利用的影响。结果表明,胡萝卜肉质根的产量、氮素吸收及可溶性固形物含量随施氮量的增加而明显增加,但在氮素投入量超过120 kg·hm-2时肉质根的产量和可溶性固形物含量没有明显地增加。在本试验条件下,保证胡萝卜肉质根产量的最低氮供应水平(0-60 cm土壤初始无机氮+肥料氮)为227kg·hm-2,根据土壤氮素的分析,作物生长期间根层土壤的氮素净矿化量为58kg·hm-2,因此满足作物生长所需要的氮素临界供应目标值(0～60 cm土壤初始无机氮+肥料氮+根层土壤的氮素净矿化量)为285kg·hm-2,即从合理施肥的角度来看,京郊露地胡萝卜生产中氮肥的最大投入量不应超过该值。     

蚯蚓粪对番茄根际土壤微生物学特性的影响

以番茄为试材,设置单施蚯蚓粪试验和蚯蚓粪配施化肥试验2组处理,研究蚯蚓粪对番茄根际土壤微生物学特性及酶活性的影响,以期为利用蚯蚓粪有机肥改良保护地栽培土壤肥力提供参考依据.结果表明:单施蚯蚓粪和蚯蚓粪配施化肥处理均能显著增加番茄根际土壤细菌、真菌和放线菌的数量,并提高土壤微生物生物量碳氮及过氧化氢酶与脲酶活性.各处理表现的效果不同,2组试验中,60％～100％蚯蚓粪处理显著增加细菌数量,40％～100％蚯蚓粪处理显著增加真菌数量,20％～80％蚯蚓粪处理显著增加放线菌数量;20％～80％蚯蚓粪处理显著增加土壤微生物生物量碳氮,且随着蚯蚓粪含量的递增而递增;40％蚯蚓粪处理过氧化氢酶活性增加的幅度最大,脲酶活性则随蚯蚓粪含量的增加而增加.     

大豆根外追肥

生产实践证明,大豆进行根外追肥,增产效果显著。一、叶面喷施氮磷混合肥料大豆出苗后,在苗期虽然需氮量不多,但因幼苗长出第一片复叶时,子叶所含的氮素已经快耗尽,而根瘤的固氮作用尚未形成,若土壤中的氮素供应不足,就会影响正常生长;大豆出苗期到盛花期对磷的需要最为迫切,特别是苗期缺磷会使大豆根,茎,叶的生长受到抑     

黑龙江省沙棘的开发与利用

沙棘又名"醋柳"、"酸刺"、"黑棘"等,是一种小浆果植物,落叶灌木或小乔木.沙棘的适应性极强,是一种耐干旱,耐瘠薄、耐盐碱、生态幅度宽的树种,即可在200～300 mm降水量的沙漠地生存,也能在-50℃的条件下越冬;其根系发达,在多种瘠薄的土地上均能正常生长,并且须根有大量根瘤,固氮作用强,枯枝落叶能分解出可溶性酸性物,因此沙棘具有改良土壤的作用;沙棘固沙保水能力强.     

Effect of salinity and water table on growth and tolerance of plum and peach

The effects of combinations of salinity (no salt, 2000 p.p.m. or 4000 p.p.m. of CaCl₂ and NaCl, 1:1) and water table (30 cm, 60 cm or 90 cm from the soil surface), on the vegetative growth and tolerance of ‘Golden Japanese’ plum and ‘Mit Ghamre’ and ‘Balady’ peaches were studied. The plants were grown in lysimeters. The growth of the trunk, total shoot length, the increase in shoot length per cm and the fresh weight of top, root and total plant were reduced with increasing salinity of the irrigation water. The effect was accentuated when the plants were maintained at high water table level. The salinity treatments resulted in the death of 43%, 73% and 76% of the plants in the plum, and the ‘Mit Ghamre’ and ‘Balady’ peaches, respectively, indicating that the plum is more tolerant to salinity than the peach. The plants of the salinity treatments showed various symptoms of salt injury, such as leaf burn, defoliation, shoot die-back and finally death. In the peaches, salt injury started to occur in the first growing-season, whereas the salt injury appeared in the plum in the second growing-season. The symptoms were more pronounced in the 4000 p.p.m. treatment than in the 2000 p.p.m. treatment and were more pronounced at the high water table level. The salinity level was the predominant factor and the effect of the water table on the vegetative growth diminished with increase in the salinity level of the irrigation water.     

洞庭1号无籽西瓜套种棉花高产高效模式的研究与应用

根据西瓜、棉花两者生长发育特点进行套种试验,研究其高产高效栽培模式。试验示范结果表明,以西瓜行株距4.5m×0.65m,棉花行株距1.5m×0.45m的种植密度,西瓜与棉花之间互颉作用最小,西瓜和棉花的产量和产值在3个套种模式中位居第1,在5个处理中经济效益最高。     

Primary culture and identification of mouse PASMCs and effects of hypoxia on proliferation and apoptosis of PASMCs

AIM：To establish a fast, accurate and economical technique for culturing mouse pulmonary arteriolar smooth muscle cells (PASMCs), and to explore the effects of hypoxia on the proliferation and apoptosis of the PASMCs. METHODS：In sterile condition, the pulmonary artery was isolated from the male BALB/c mice by digesting with collagenase I, and the cells were cultured in fetal bovine serum-coated flask. Centrifugal procedure was not used during the cell passage. The cell morphology was observed under an inverted phase-contrast microscope. α-Smooth muscle actin was identified by immunocytochemistry and immunofluorescence. The effects of hypoxia on the proliferation and apoptosis of the PASMCs were detected by CCK-8 assay and TUNEL assay. RESULTS：PASMCs were identified by the methods of immunocytochemistry, immunofluorescence staining and observation of morphology. Unlike the rat PASMCs with typical subcultured peak-vally pattern, the mouse PASMCs showed a lot different without a peak-vally pattern. The cells could be subcultured after 5 d to 7 d and there was 3 to 5 generations depending on the activity of the cells. CCK-8 assay demonstrated that the A values of PASMCs exposed to hypoxia increased after 24 h (P＜0.05) as compared with normoxia. TUNEL result showed that the apoptotic index of the PASMCs in hypoxia decreased after 24 h (P<0.05). CONCLUSION：This technique for obtaining cultured mouse PASMCs is simple, fast, accurate and economical. The digestion time is easy to control. Hypoxia promotes the proliferation and inhibits the apoptosis of PASMCs.     

世界及中国鳄梨产销概况与展望

依据联合国粮食及农业组织(FAO)数据库、联合国商品贸易统计数据库(UN Comtrade)中的数据,围绕鳄梨种植面积、产量、迚出口市场、主产国生产情况、主要迚出口国贸易情况等斱面,对世界及中国鳄梨的生产与贸易迚行回顾、分析与展望,幵在此基础上,对中国鳄梨产业的发展提出建议。     

Storability of onion seeds and effects of packaging and storage conditions on viability and vigour

Fresh onion seeds desiccated to 6.0% seed moisture content (SMC) were stored in various packaging materials under different storage conditions. Seeds packed in aluminum-laminated pouches beside those stored with silica gel at 25 °C maintained satisfactory germinability and vigour after 12 months. Desiccated seeds stored in moisture impervious containers produced more vigourous seedlings. Germination potential of onion seeds increased with reduced SMC besides storage in moisture impervious packets along with desiccants as physiological and biochemical attributes are regulated. Seed viability and vigour decreased with accelerated ageing due to increased lipid peroxidation, decreased activities of several free radical and peroxide scavenging enzymes. Electrical conductance of seed leachates also increased with ageing. Thus, adoption of appropriate storage temperature and moisture control techniques would significantly affect onion seed quality, which was due to minimum accumulation of free peroxide radicals and enhanced activity of free radical scavenging enzymes.     

小檗碱和壳聚糖抗蔬菜病原真菌活性测定及复合膜制备

研究了小檗碱和壳聚糖对几种常见蔬菜病原真菌的抑制活性,以及以小檗碱和壳聚糖为主料制备复合膜的方法,并测定了该膜的药物释放效果。试验表明:低浓度(0.234 mg/mL)小檗碱即可抑制辣椒炭疽病菌(Vermicularia capsici)等5种蔬菜病原真菌的生长。20 mg/mL浓度壳聚糖对番茄灰霉病菌(Botrytis cinerea)的抑制率高达65%,而对其余4种果蔬病原真菌也有一定的抑制作用。为了集成这2种天然化合物的优点,制备了小檗碱-壳聚糖复合膜,该膜具有缓释功能,在模拟外部环境(磷酸缓冲液,pH 6.8)条件下,20 d小檗碱累计释放率接近25%,提示其在果蔬贮藏抗菌中的应用价值。     

西瓜与粮油菜套种栽培试验

近年来,我省西瓜发展速度较快,到2004年全省西瓜栽培面积已达3万hm^2.由于我省耕地面积有限,大幅度扩大西瓜单种面积,不仅造成我省西瓜与粮油菜争地的矛盾,而且土地也未能得到充分有效的利用.为了解决这一生产中存在的实际问题,我们从2002年开始,进行了西瓜与粮油菜套种的栽培试验.历经4年的试验、示范,取得了显著的经济效益和社会效益.现将试验结果报告如下.     

热处理对果蔬采后品质及病虫害的影响

采后热处理是近年来快速发展的果蔬采后处理技术,广泛应用于改善果蔬贮藏期间的品质、增强抗逆性等 方面。从果蔬贮藏期间的生理生化、采后品质及防治病虫害等方面阐述了热处理的机理,讨论了热处理对果蔬衰老 方面的生理特征如色泽、风味、硬度(软化)、失重、呼吸、乙烯释放、酶活性等变化及与抗逆性有关的诱导蛋白质合成 及基因表达的影响,较全面阐述了热处理防治果蔬贮藏期间病虫害的机理如直接作用于病菌、害虫与提高果蔬的抗 病虫性等。     

陕西冬枣黑斑病和炭疽病病原菌的分离鉴定及特征比较

以大荔县冬枣种植区采集的发病枣果为试材,采用常规组织分离法进行病原菌的分离纯化,通过柯赫氏证病法则、形态学观察及分子生物学分析,研究鉴定了冬枣黑斑病和炭疽病的病原菌种类,并采用田间调查法对2种病害为害特征进行比较分析,以期为田间有效区分冬枣黑斑病和炭疽病为害症状,并快速判断其病原类型,及进一步深入开展精准防控提供参考和指导.结果表明:陕西大荔冬枣黑斑病的病原菌为细极链格孢(Alternaria tenuissima),炭疽病的病原菌为胶孢炭疽菌(Colletotrichum gloeosporioides).2种病害均主要为害枣果实,在枣果果腰或果肩上形成黑褐色病斑,可能同时存在且症状相近极易混淆,但在病斑表面、皮下及久置表型3个方面存在明显区别.     

钾肥在小白菜和萝卜上的施用效果

采用盆栽试验方法研究了施用钾肥对小白菜、萝卜生长发育、产量、品质及钾素含量的影响。结果表明 ,施用钾肥对小白菜和水萝卜的株高、叶片数无显著的影响 ,但可提高水萝卜块根的产量 ,提高幅度为 31.0 4 %～ 97.93%。施用钾肥可提高小白菜和萝卜的蛋白质和VC含量 ,降低硝酸盐含量 ,增加植株的钾素含量