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为比较V形水平叶幕和V形下垂叶幕对香百川葡萄光能截获和利用的影响，测定2种叶幕类型下叶绿素含量、生长季的叶片光合能力、叶面积及光能和光谱截获率。结果表明，与V形水平叶幕相比，V形下垂叶幕显著提高了4～20节位叶片的叶绿素含量，提高了4～16节位叶片的叶面积，提高了叶幕投影范围内的光能截留率和400～800 nm波长范围的光谱截获率。下垂叶幕放缓了中上部节位叶片发育速度，生长前期下垂叶幕12～16节位叶片光合能力低于水平叶幕，随后光合能力迅速提高，至花后14周6～16节位叶片的净光合速率显著高于水平叶幕。 相似文献
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为探究臭氧（O3）胁迫及恢复过程中葡萄叶片光系统活性的响应,以1年生‘赤霞珠’葡萄（Vitis vinifera L.‘Cabernet Sauvignon’）为试材,设置臭氧 + 弱光（90 nL · L-1 O3 + 10 μmol · m-2 · s-1）、臭氧 + 适光（90 nL · L-1 + 800 μmol · m-2 · s-1）、臭氧 + 强光（90 nL · L-1 + 1 600 μmol · m-2 · s-1）3种处理,均处理3 h,以大气臭氧浓度、适光处理（10 nL · L-1 + 800 μmol · m-2 · s-1）作为对照,分别测定处理后1、5、9和13 h的叶片气体交换参数,同时利用Dual-PAM100荧光仪测定叶片PSⅠ及PSⅡ光系统活性分析臭氧胁迫及恢复过程中光系统活性的响应。结果表明：臭氧胁迫可以降低葡萄净光合速率和气孔导度,同时降低了叶片的Y(Ⅰ)和Y(Ⅱ)值,在相同臭氧浓度下,随着光照增强叶片受到的伤害加大。恢复13 h后,臭氧弱光和臭氧适光处理的叶片净光合速率、Y(Ⅰ)和Y(Ⅱ)值回升,但臭氧强光处理的叶片伤害不断加深,光系统活性不能得到恢复。 相似文献
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以盆栽‘赤霞珠’葡萄为试验材料,浇施浓度为100 nmol·L~(-1)的外源褪黑素(melatonin)后,在110 n L·L~(-1)臭氧浓度胁迫下,测定葡萄叶片气体交换参数和叶绿素荧光快速诱导动力学曲线,并结合叶绿素荧光淬灭分析葡萄叶片光合性能的变化。结果表明:浇施褪黑素提高了臭氧胁迫下叶绿素a、b和类胡萝卜素的含量以及叶绿素a/b的比值,提高了叶片净光合速率(P_n)和叶片单位面积有活性反应中心的数量(RC/CSm),以及捕获的激子将电子传递到Q_A以后的其他电子受体的概率(Ψ_o),从而缓解了臭氧胁迫下的光抑制程度。结论:外源褪黑素缓解了臭氧胁迫下葡萄叶片叶绿素的降解,通过调节光系统的能量分配,缓解了臭氧胁迫对光合作用的伤害。 相似文献
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“厂字”架式对“赤霞珠”葡萄光合效率和果实品质的影响 总被引：3，自引：0，他引：3
以5年生"赤霞珠"葡萄为试材,研究了不同叶幕高度的"厂字"架式对酿酒葡萄光合效率和果实品质的影响,以提高贺兰山东麓酿酒葡萄的果实品质。结果表明:与"独龙蔓"架式相比,"厂字"架式处理提高了酿酒葡萄叶片比叶重和叶绿素含量,120cm和150cm叶幕高度的"厂字"架式处理显著提高了叶片光合效率、果实中总糖、花色素和总酚含量,没有显著影响平均单果重和可滴定酸含量,使果实品质得到显著提高。因此,在宁夏酿酒葡萄产区,120cm叶幕高度"厂字"架式可通过调节叶片的发育和光合效率,进而显著提高了酿酒葡萄果实的品质。 相似文献
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《中国果树》2017,(5)
为了提高感染卷叶病毒的酿酒葡萄品质,试验以感染卷叶病毒的‘蛇龙珠’葡萄为试材,研究叶面喷施不同浓度水杨酸对葡萄叶片光合作用、果实品质的影响。结果表明:水杨酸处理不能显著抑制葡萄叶片中卷叶病毒的侵染,但可以提高叶片叶绿素含量和净光合速率,提高果实中转化酶活性,促进糖分积累;葡萄谢花后20 mg/L水杨酸处理显著提高了叶片叶绿素含量和1,5-二磷酸核酮糖羧化/加氧酶(Rbuisco)活性,叶片净光合速率显著升高,同时也显著提高了果实中转化酶活性,提升果实品质。因此,葡萄谢花后适宜浓度的水杨酸处理可以通过提高叶片光合能力和果实中糖分积累相关酶活性来提高感染卷叶病毒葡萄的果实品质。 相似文献
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二氧化硫和臭氧对巨峰葡萄酶促褐变的影响 总被引：7，自引：0，他引：7
采用CT2号葡萄保鲜剂和臭氧在 (0± 1)℃下贮藏巨峰葡萄 ,结果表明 ,利用臭氧多次处理能有效地防止葡萄腐烂 ,果实外观无伤害 ,但与CT2号葡萄保鲜剂处理相比 ,加速了果实抗坏血酸和单宁等物质的氧化及可滴定酸的消耗 ,促进了果肉组织的酶促褐变 ,但没有SO2 残留。而CT2号保鲜剂处理可减少果肉可滴定酸、抗坏血酸和单宁物质的损失 ,降低果肉组织的酶促褐变率 ,但部分果实受到SO2 漂白伤害且果肉组织有SO2 残留 相似文献
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为探明山葡萄叶片低温伤害的生理机制,以抗寒性差异明显的‘双丰’(山葡萄种内杂交种)和‘左优红’(种间杂交种)为试材,对低温处理过程中叶绿素荧光参数和活性氧代谢的相关指标进行测定。结果表明,随低温胁迫加剧,两个品种叶片的叶绿素含量、Chl.a/b、Fv/Fm值均呈显著下降趋势,1–qp值及MDA含量明显增加;整个胁迫过程中NPQ值较稳定的‘双丰’其叶片遭受低温伤害程度较轻,NPQ值一直下降的‘左优红’叶片伤害程度较重,‘双丰’的NPQ值始终显著高于‘左优红’。‘双丰’叶片的SOD和APX活性始终较‘左优红’高。说明低温使山葡萄叶片叶绿素分解,PSⅡ电子传递受阻,激发能增加,造成叶绿体膜脂过氧化损伤;热耗散及抗氧化酶共同作用减轻了活性氧对叶片PSⅡ的伤害程度。由此可见,热耗散NPQ值及活性氧清除酶SOD和APX活性的差异可能是造成两个山葡萄品种叶片低温伤害程度不同的重要原因。 相似文献
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This paper introduces a method to study the temporal relationship between the distribution of trees in cities and the residents’ income, rate of home ownership and level of education. Through photo-interpretation methods, it documents tree cover percentages in five inner city Local Government Areas in Melbourne. A 10-year time frame (2001–2011) is examined. Prior socioeconomic indicators are juxtaposed against future tree cover levels to investigate relationships. This study demonstrates that tree cover inequity is increasing over time in Melbourne. The study indicates that prior income level is a fair precursor to future canopy cover. By comparing different tree policy approaches of the five adjacent local government areas in Melbourne, it is identified that progressive policy helps generate positive outcomes for the urban forest. 相似文献
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Bugbee B 《HortScience : a publication of the American Society for Horticultural Science》1992,27(7):770-776
This paper describes the use of a commercial growth chamber for canopy photosynthesis, respiration, and transpiration measurements. The system was designed to measure transpiration via water vapor fluxes, and the importance of this measurement is discussed. Procedures for continuous measurement of root-zone respiration are described, and new data is presented to dispel myths about sources of water vapor interference in photosynthesis and in the measurement of CO2 by infrared gas analysis. Mitchell (1992) has described the fundamentals of various approaches to measuring photosynthesis. Because our system evolved from experience with other types of single-leaf and canopy gas-exchange systems, it is useful to review advantages and disadvantages of different systems as they apply to various research objectives. 相似文献
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Remote sensing data are typically collected at a scale which is larger in both grain and extent than traditional ecological measurements. To compare with remotely sensed data on a one-to-one basis, field measurements frequently must be rescaled to match the grain of image data. Once a one-to-one correspondence is established, it may be possible to extrapolate site based relationships over a wider extent. This paper presents a methodology for rescaling the grain of ecological field data to match the grain of remotely sensed data and gives an example of the method in verification of remote sensing estimates of canopy water content in a tidal salt marsh. We measured canopy water content at 169 points on a semi-regular grid in the Petaluma Marsh, CA. A variogram describing the spatial correlation structure of the canopy water content was calculated and modeled. Ordinary kriging estimates of the canopy water content were calculated over blocks corresponding to image pixels acquired by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). A water content index was determined from the reflectance data by calculating the area of a water absorption feature at 970 nm. A regression developed between the blocks and the pixels at the site was extrapolated over the image to obtain an estimate of canopy water content for the entire marsh. The patterns of canopy water content at the site and landscape levels suggest that different processes are important for determining patterns of canopy water content at different spatial extents. The errors involved in the rescaling procedures and the remote sensing interpretation are discussed. 相似文献
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Urban trees provide a wide range of ecosystem services for city residents, with tall, mature trees with wide crowns generally regarded as preferable. The tree biomass which is responsible for shading, pollution removal, rain runoff retention etc. gets periodically reduced by the municipal tree management practice of pruning. This is a necessary activity, which reduces the risk of infrastructure damage and falling branches, but many estimates of ecosystem service provision in cities do not consider its impact explicitly. Tree mortality is also higher in cities, preventing trees from attaining and remaining at large sizes. This study used extensive field measurements of tree structure to estimate the impact of pruning on 8 tree species in two Italian cities: Taranto and Florence. Crown widths were reduced by 1.6 m on average, however there is large variation between species variation with branches more often being removed for thinning crowns resulting in larger gap fractions, which increased by 15% on average. No significant differences were observed for crown widths or gap fraction between trees pruned 3 and 4 years previously, suggesting that tree crowns structurally recover from pruning after 3 years. A deterministic model revealed that current urban forest pruning rates (every 6 years) and mortality (1%) may create a situation in which a city dominated by the species studied benefits from 93.5% of the maximum ecosystem services possible. This work will allow more nuanced estimates of urban forest services to be calculated. 相似文献
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Urban stormwater is a major contributor to surface water degradation in the United States, prompting cities to invest in ways to naturally capture, store, and slowly release runoff through green infrastructure (GI). An often overlooked, yet integral, component of GI is urban tree canopy, which functions as GI through the process of rainfall interception (i.e., rainfall captured and stored within the canopy prior to returning to the atmosphere via evaporation). Nine trees from three native species commonly found in urban areas in the southeastern United States were studied in three parks in Knoxville, TN, USA to quantify interception. Throughfall (rainfall that passes through the canopy) and stemflow (rainfall that travels down the trunk) data were collected with continuous measurements by a network of automatic rain gauges positioned underneath each tree canopy. Data were collected from January 2018 to May 2019 which resulted in 98 storm events collected for each red maple (Acer rubrum) and willow oak (Quercus phellos), and 97 storm events collected for each white pine (Pinus strobus). Annually, red maples, white pines, and willow oaks intercepted 24.4%, 52.4%, and 33.2% of gross throughfall, respectively. Seasonally, white pines performed the most consistently with interception varying only from 49.2% to 57.0% between seasons compared to an interception range of 13.2–39.7% and 17.5–54.2% for red maples and willow oaks, respectively. Results demonstrated the effect of event duration, rainfall intensity, and seasonality on the interception potential of each species. Overall, these observations are a step toward allowing the storage capacity of urban trees to be properly credited as part of efforts to reduce stormwater runoff. 相似文献