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101.
102.
为了研究在相同立地和养分供给条件下,不同桉树的生物量和营养元素(N、P、K)累积量及其分配特征,以1年生9种桉树(尾叶桉、窿缘桉、细叶桉、大叶桉、赤桉、巨桉、粗皮桉、托里桉、大花序桉)为材料,通过测定树根、树干、树皮、叶片、树枝5个器官的生物量以及氮、磷、钾含量,了解养分吸收和分配情况,揭示生物量构成特点。结果表明:9种桉树总生物量最大的是赤桉,为711.20 g·株-1,其次是托里桉、粗皮桉、巨桉、大叶桉、细叶桉、尾叶桉和大花序桉,窿缘桉的生物量最小,为69.20 g·株-1。不同器官生物量分配规律为树干或叶片最大,树根、树枝、树皮次之。不同器官营养元素含量为叶片最高,树干最低。9树种营养元素累积总量由高到低排序为赤桉(29)托里桉(29)巨桉(29)大叶桉(29)粗皮桉(29)细叶桉(29)尾叶桉(29)大花序桉(29)窿缘桉,各树种对3种元素累积量均为N最多,其次是K,P最少;9树种对N、P和K的吸收效率范围为分别为0.80%~7.69%,0.11%~1.32%和0.61%~10.38%;吸收效率最高的为赤桉,最低的为大花序桉,而其他桉树对各元素的吸收效率规律各不相同。 相似文献
103.
文章将木材预干的方法分为三类,并分别阐述了各类预干法的概念、特点,并从木材内部水分子移动的规律及外部空气自然循环着手,对木材预干的机理进行了论述。针对采用气干预干法操作的企业提出了几点注意事项。就北方林区预干法的使用提出了具体建议。 相似文献
104.
通过一系列的调查、统计及数据分析,其结果证明了赣县在长防林工程实施后森林资源显著增长,水土流失大幅度减少,生态环境不断改善. 相似文献
105.
In this paper the optimal model of repaying debt combined with operational research and technology economics was presented. It is for solving the problem to increase the benefit of project in terms of planning to repay capital with interest. 相似文献
106.
采用不同方法对猪屎豆种子进行处理,并测定了种子的硬实率、吸水率和发芽率.结果表明:猪屎豆种子有较高的硬实率,砂纸摩擦5 min可显著提高种子的吸水率;砂纸摩擦1~7 min均可提高种子的萌发率,摩擦5 min的发芽率达36%,而未摩擦种子发芽率只有11.3%.丙酮处理种子1、2、3、4h不能提高种子的发芽率,时间越长,种子的发芽率越低;过氧化氢处理对种子的催芽没有显著的效果;摩擦后种子在室温(10 ~27℃)、15、25、30、35℃条件下均能萌发;光照对种子的萌发没有显著的影响,说明猪屎豆种子是中光种子. 相似文献
107.
Far-red(FR) light regulates phytochrome-mediated morphological and physiological plant responses.This study aims to investigate how greenhouse tomato morphology and production response to different durations of FR light during daytime and at the end of day(EOD).High-wire tomato plants were grown under intra-canopy lighting consisting of red(peak wavelength at 640 nm) and blue(peak wavelength at 450 nm) light-emitting diodes(LEDs) with photosynthetic photon flux density(PPFD) of 144 μmol m–2 s–1 at 10 cm away from the lamps,and combined with overhead supplemental FR light(peak wavelength at 735 nm) with PPFD of 43 μmol m–2 s–1 at 20 cm below the lamps.Plants were exposed to three durations of FR supplemental lighting including: 06:00–18:00(FR12),18:00–19:30(EOD-FR1.5),18:00–18:30(EOD-FR0.5),and control that without supplemental FR light.The results showed that supplemental FR light significantly stimulated stem elongation thereby resulting in longer plants compared with the control.Moreover,FR light altered leaf morphology toward higher leaf length/width ratio and larger leaf area.The altered plant architecture in FR supplemented plants led to a more homogeneous light distribution inside the canopy.Total plant biomass was increased by 9–16% under supplemental FR light in comparison with control,which led to 7–12% increase in ripe fruit yield.Soluble sugar content of the ripe tomato fruit was slightly decreased by longer exposure of the plants to FR light.Dry matter partitioning to different plant organs were not substantially affected by the FR light treatments.No significant differences were observed among the three FR light treatments in plant morphology as well as yield and biomass production.We conclude that under intra-canopy lighting,overhead supplemental FR light stimulates tomato growth and production.And supplementary of EOD-FR0.5 is more favorable,as it consumes less electricity but induces similar effects on plant morphology and yield. 相似文献
108.
LI Feng YAO Li ZHANG Xi-hong XIA Yu-hong CHENG Jie LOU Xue-ling JIANG Qiu-hui 《园艺学报》2016,32(12):2251-2255
AIM: To examine the expression of miRNA-22 in the ovarian tissues and the effect of miRNA-22 over-expression on the proliferation, migration and invasion in SKOV-3 cells. METHODS: The expression levels of miRNA-22 in different ovarian tissues and SKOV-3 cells were determined by qPCR. miRNA-22 was over-expressed by transfection of miRNA-22 mimic. The cell viability was examined by CCK-8 assay. The cell migration was measured by wound healing test. The cell invasion was analyzed by Transwell assay. The protein expression levels of VEGF and P53 were determined by Western blot. RESULTS: Compared with the normal ovarian tissue, the expression level of miRNA-22 was remarkably decreased in the ovarian tumor tissues. After transfection with miRNA-22 mimic, the expression level of miRNA-22 in the SKOV-3 cells was significantly increased, while the cell viability, migration and invasion were obviously decreased. Moreover, the protein expression of VEGF and P53 was dramatically inhibited after over-expression of miRNA-22. CONCLUSION: The decreased miRNA-22 expression may be correlated with the development of ovarian can-cer. Over-expression of miRNA-22 decreases the cell viability, migration and invasion by reducing the protein expression of VEGF and P53. 相似文献
109.
跨区作业经济效益影响因素剖析 总被引:4,自引:0,他引:4
根据2004年跨区作业调查,计算了联合收割机跨区机收的经济效益,并着重指出了跨区作业经济效益下降的实际问题;通过深入分析其中的原因,指出影响跨区作业经济效益的两大主要因素,是信息系统不完善和散机的无序流动。 相似文献
110.
针对近年来商用车侧翻事故的凸现,提出了一种利用空气悬架提高车辆倾翻阀值,减小车辆倾翻危险的方法,编写了控制器,在MATLAB中SIMULINK下建立了七自由度车辆模型,并进行了仿真。仿真结果表明,半主动空气悬架能够有效提高车辆倾翻阀值,提高车辆抗侧翻能力。 相似文献