排序方式： 共有10条查询结果，搜索用时 15 毫秒
1
1.
Effects of deficit irrigation strategies on cluster microclimate for improving fruit composition of Moscatel field-grown grapevines 总被引：1，自引：0，他引：1
Tiago Pedreira dos Santos Carlos M. Lopes M. Lucília Rodrigues Claudia R. de Souza Jorge M. Ricardo-da-Silva João P. Maroco João S. Pereira M. Manuela Chaves 《Scientia Horticulturae》2007
The grapevine plays a very important role in the economic, social and cultural sectors of many regions; however vineyards are often grown in regions under stressful conditions and thus they are vulnerable to climate change. The objective of this research was to investigate the effect of partial root-zone drying (PRD) irrigation on vine water relations, vegetative growth, plant microclimate, berry composition and yield components, compared to conventional deficit irrigation (DI, 50% ETc), full irrigation (FI, 100% of ETc) and non-irrigated vines (NI). The study was undertaken in mature ‘Moscatel’ grapevines (Vitis vinifera L.) grown in Pegões, South of Portugal. Compared to the other irrigated treatments, PRD vines showed a better microclimate at the cluster zone with higher incident photosynthetic photon flux density (PPFD). Within the more open canopies of NI and PRD treatments, berry temperatures were higher than those of denser ones (DI and FI). Compared to the conventional irrigation technique the better microclimate observed in PRD vines was a consequence of a reduction in vine growth, where lower values of leaf layer number, leaf area, canopy wideness, water shoots and shoot weight were observed. In PRD vines we observed a tendency to a development of a deeper root system, while DI and FI showed a more homogeneous root distribution throughout the different soil layers. PRD showed an improvement in berry quality with higher values of flavour precursors, and total phenols concentration without any significant yield reduction compared to DI and FI. 相似文献
2.
Deficit irrigation based on drought tolerance and root signalling in potatoes and tomatoes 总被引：1，自引：0，他引：1
Christian R. Jensen Adriano Battilani Georgios Psarras Franciszek Janowiak Zorica Jovanovic Xuebin Qi Sven-Erik Jacobsen 《Agricultural Water Management》2010,98(3):403-384
Agriculture is a big consumer of fresh water in competition with other sectors of the society. Within the EU-project SAFIR new water-saving irrigation strategies were developed based on pot, semi-field and field experiments with potatoes (Solanum tuberosum L.), fresh tomatoes (Lycopersicon esculentum Mill.) and processing tomatoes as model plants. From the pot and semi-field experiments an ABA production model was developed for potatoes to optimize the ABA signalling; this was obtained by modelling the optimal level of soil drying for ABA production before re-irrigation in a crop growth model. The field irrigation guidelines were developed under temperate (Denmark), Mediterranean (Greece, Italy) and continental (Serbia, China) climatic conditions during summer. The field investigations on processing tomatoes were undertaken only in the Po valley (North Italy) on fine, textured soil. The investigations from several studies showed that gradual soil drying imposed by deficit irrigation (DI) or partial root zone drying irrigation (PRD) induced hydraulic and chemical signals from the root system resulting in partial stomatal closure, an increase in photosynthetic water use efficiency, and a slight reduction in top vegetative growth. Further PRD increased N-mineralization significantly beyond that from DI, causing a stay-green effect late in the growing season. In field potato and tomato experiments the water-saving irrigation strategies DI and PRD were able to save about 20-30% of the water used in fully irrigated plants. PRD increased marketable yield in potatoes significantly by 15% due to improved tuber size distribution. PRD increased antioxidant content significantly by approximately 10% in both potatoes and fresh tomatoes. Under a high temperature regime, full irrigation (FI) should be undertaken, as was clear from field observations in tomatoes. For tomatoes full irrigation should be undertaken for cooling effects when the night/day average temperature >26.5 °C or when air temperature >40 °C to avoid flower-dropping. The temperature threshold for potatoes is not clear. From three-year field drip irrigation experiments we found that under the establishment phase, both potatoes and tomatoes should be fully irrigated; however, during the later phases deficit irrigation might be applied as outlined below without causing significant yield reduction:
- •
- Potatoes
- °
- After the end of tuber initiation, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.
- •
- Fresh tomatoes
- °
- From the moment the 1st truce is developed, DI is applied at 85-80% of FI for two weeks. In the middle period, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.
- •
- Processing tomatoes
- °
- From transplanting to fruit setting at 4th-5th cluster, the PRD and DI threshold for re-irrigation is when the plant-available soil water content (ASWC) equals 0.7 (soil water potential, Ψsoil = −90 kPa). During the late fruit development/ripening stage, 10% of red fruits, the threshold for re-irrigation for DI is when ASWC = 0.5 (Ψsoil = −185 kPa) and for PRD when ASWC (dry side) = 0.4 (Ψsoil, dry side = −270 kPa).
3.
采用计算机和N16251数据采集卡为硬件核心,以LabVIEW为软件开发平台,设计一个实时振动测量系统。该系统通过振动传感器采集现场振动信号,由开发的软件平台分析和处理采集信号,对振动数据进行实时测量和采集。同时将来集的数据存储,已备进行查阅和分析。测试结果表明,该系统界面友好,测量精度高,安全可靠,易于操作. 相似文献
4.
岳明明 《拖拉机与农用运输车》2014,(1):11-14,18
针对大功率拖拉机传动系室内试验的特点和难点,提出了可行的解决方案。基于NI LabVIEW虚拟仪器平台建立了传动系仿真试验系统,找到了实现差速器"电轴"连锁的控制方法,并通过试验进行了技术验证。 相似文献
5.
四川松茸的特殊生态研究 总被引：7，自引：0，他引：7
四川松茸生态特殊。经研究表明:产菇地海拔高1900—3900米,坡度陡,可达70度;属山地寒温带湿润(或半湿润)气候,旱雨季分明,产菇于雨季,光照强,气温低、年较差小,日较差大;植被不为松、杉乔木,而多为栎,栲矮灌丛(或高灌丛、乔木)。由于特殊生态环境,松茸发生时间在7—9月,比日本早2—3个月上市,少病虫害、香味特浓,经济性状好。四川松茸特殊生态的发现,扩大了我国松茸的分布地区及松茸的共生植物范围,为此菌的生态研究提供了新内容,为开发松茸新产区及半人工栽培研究提供了依据。 相似文献
6.
Li-Ping Hu Fan-Zhen Meng Shao-Hui Wang Xiao-Lei Sui Wei Li Yu-Xia Wei Jian-Lei Sun Zhen-Xian Zhang 《Scientia Horticulturae》2009
Levels of carbohydrates and activities of metabolic enzymes were examined in leaves (source), phloem sap (flow) and mesocarp tissues (sink) in the course of cucumber (Cucumis sativus L.) fruit development, from 2 days before anthesis to 20 days after anthesis. While total sugar levels increased in all the three sampling organs, starch levels declined in leaves and mesocarp tissues as fruit development progressed. Glucose and fructose were the primary contributors to the soluble sugar pools in mature leaves. Stachyose was found as the most important component of the phloem sap extracts, followed by sucrose and raffinose. However, the primary sugars accumulated in mesocarp tissues were glucose and fructose, not stachyose or sucrose. Activities of sucrose synthesizing enzymes (sucrose phosphate synthase plus sucrose synthase in the synthesizing direction) exceeded that of sucrose degrading enzymes (acid invertase, neutral invertase plus sucrose synthase in the degrading direction) in leaves, which might cause a sucrose pool utilized in raffinose and stachyose biosynthesis. While alkaline a-galactosidase form I activity declined, stachyose synthase activity showed a rapid increase until 12 days after anthesis and only subsequently decreased in leaves. Activities of sucrose degrading enzymes were always much higher than that of sucrose synthesizing enzymes in mesocarp tissues. Thus, sucrose accumulation could not occur in mesocarp tissues. While stachyose synthase activity steadily decreased, alkaline a-galactosidase form I activity showed a moderate increase before decrease in mesocarp tissues. The relationship between levels of soluble sugars and activities of relative enzymes was also discussed. 相似文献
7.
甘蔗是一种重要的经济作物,在全球蔗糖生产中占主导地位。当前研究者们正致力于通过揭示蔗糖代谢的复杂性而提高蔗茎蔗糖分。为研究探讨甘蔗工艺成熟期不同阶段早熟（高糖）品种和晚熟（低糖）品种的叶片转化酶活性,测定了早熟和晚熟甘蔗品种光合作用很强的第3叶的可溶性酸性转化酶、中性转化酶活性以及叶片酸性转化酶与中性转化酶活性。结果表明,低糖甘蔗品种叶片的酸性转化酶活性较高,而中性转化酶活性较低。相关分析结果表明,叶片酸性转化酶活性与蔗糖分呈负相关,而与己糖含量呈正相关;相反,叶片中性转化酶与蔗糖分呈正相关,与己糖含量呈负相关。研究结果说明,不管甘蔗品种的熟性表现如何,其叶片转化酶在甘蔗糖分调节中均起主导作用。 相似文献
8.
针对电子电路相关课程中工程实践教育面临的问题，结合具体实例介绍了NI新推出的便携式教学设备．NImyDAQ专为课堂和实验室之外的实验而设计，可以让学生随时随地进行工程实践．该实践创新平台不仅有助于提高学生的工程实践能力，让学生从书本理论过渡到工程实践，而且有利于学生工程创新意识的培养． 相似文献
9.
李梦军 《河北北方学院学报(自然科学版)》2011,27(6):29-31,35
针对电子电路相关课程中工程实践教育面临的问题，结合具体实例介绍了NI新推出的便携式教学设备．NImyDAQ专为课堂和实验室之外的实验而设计，可以让学生随时随地进行工程实践．该实践创新平台不仅有助于提高学生的工程实践能力，让学生从书本理论过渡到工程实践，而且有利于学生工程创新意识的培养． 相似文献
10.
NI Multisim 10是目前各种电子电路辅助分析与设计软件中最优秀的软件之一,具有模拟和数字电路的设计、分析、仿真功能.为探讨NI Multisim 10在单片机控制系统设计方面的应用,提出一种基于NI Multisim 10软件、用单片机控制交通信号系统的电路设计方案,并对电路系统进行仿真与调试,旨在为NI Multisim 10软件在控制系统中的应用提供有益参考. 相似文献
1