“灵武长枣”的介电特性和内在品质的关系

以宁夏地方特色农产品"灵武长枣"为研究对象,在货架期间利用LCR测试仪在特征频率223.8kHz(105.35 kHz)下测试了长枣并联等效电容(Cp)、电导(G)、阻抗相角(θ)、复阻抗(Z)等电学指标;并对与长枣的果皮破裂强度、脆度、果肉坚实度等物理力学品质指标和水分含量、可滴定酸含量、可溶性固形物含量等化学品质指标进行了比较分析,以筛选出相关性强的特征电学参数;在此基础上对电学参数与品质指标的变化规律进行了回归分析,以探讨基于介电特性的"灵武长枣"无损检测、品质评价的可行性。结果表明:"灵武长枣"的品质指标(果皮破裂强度、脆度、果肉坚实度、水分含量、可溶性固形物含量)与电学参数(Cp、G、θ、Z)具有很强的相关性,达到差异显著水平(P<0.05),对其品质指标所建立的电参数模型可有效预测长枣品质;利用"灵武长枣"的介电特性参数预测评价长枣的内在品质是可行的。     

利用电学参数和机器学习无损检测番茄可溶性固形物含量

利用电学参数和机器学习建立番茄可溶性固形物含量的预测模型。使用LCR测试仪检测0.1、1、10、100、1 000 kHz频率下的番茄并联等效电容、并联等效电阻、品质因子等9项电学参数,利用皮尔逊相关系数分析并确定电学特性的特征变量,基于特征变量构建番茄可溶性固形物含量的3种无损检测模型：BP神经网络(BpNN)、多元线性回归(MLR)、支持向量回归(SVR)。结果表明,在10kHz频段下,品质因子、损耗因子、偏转角、并联等效电容及并联等效电阻5个电学参数与番茄可溶性固形物含量相关性显著。将这5个电学参数作为模型输入变量,可溶性固形物含量作为输出变量,经验证SVR模型对可溶性固形物含量的预测效果最好,决定系数R²为0.951,均方根误差RMSE为0.122,平均绝对误差MAE为0.082。本研究为番茄采后可溶性固形物含量快速无损检测提供了一种新方法。     

新红星苹果高CO_2处理的最佳指标研究

试验以定量式气调手段,研究新红星苹果高 CO_2处理的直接效应和残留效应。两年的研究结果表明:新红星苹果通风库 MA 贮藏的高 CO_2处理的最佳指标是25%-30%CO_2处理46天。处理后的果实于通风库内 MA(自发气调)贮藏5个多月(采后194天)。果实无CO_2伤害,品质好,果肉硬度高达6.2kg/cm~,虎皮病指数为零,贮效极显著地高于对照。     

钙对新红星苹果果实品质的影响

新红星苹果(starkrimson)是我国近年发展起来的颇受欢迎的品种,由于其在生产上大面积栽植,迫切需要建立相应的处理手段,以保证果品的采后保鲜及运输销售。许多试验结果证明钙能有效地延缓果实后熟衰老,延长果实的贮藏寿命,本研究以新红星苹果为试材,探讨了钙对果实可溶性蛋白质、氨基酸含量及果实品质的影响。     

不同品种授粉对鲁丽苹果坐果及果实品质的影响

以自然授粉作为对照,研究6个授粉品种对鲁丽苹果的坐果率及果实品质的影响。结果表明：6个授粉品种的鲁丽苹果坐果率均高于65%,较对照均有明显提高;6个授粉品种对鲁丽苹果的单果重、果形指数、可溶性固形物、可滴定酸及糖组分含量均有不同程度影响。新红星授粉后,可以改善鲁丽的果形指数,提高果糖葡萄糖含量。红玛瑙可提高鲁丽的可溶性固形物含量,果糖、蔗糖含量,降低可滴定酸含量,增强固酸比,改善了风味。乙女授粉后果实单果重最高。综合考虑,建议采用新红星、红玛瑙作为鲁丽的授粉品种,具有较好的坐果率和果实品质。     

‘华硕’苹果采收期判定及其对贮藏品质的影响

【目的】明确‘华硕’苹果采收期的有效判定方法,并确定‘华硕’苹果的最佳采收期。【方法】对不同采收成熟度的‘华硕’果实进行淀粉染色,分析品质指标参数之间的差异性和相关性;同时对不同采收期‘华硕’苹果进行低温与货架期贮藏,测定主要品质变化情况。【结果】乙烯释放速率、淀粉染色指数与糖酸比是可以判定‘华硕’苹果采收成熟度的可靠指标。采收期Ⅱ的‘华硕’苹果在采收时以及冷藏和货架期均表现出较好的品质。货架末期,采收期Ⅱ的果实硬度、可溶性糖含量和可滴定酸含量分别为1.52 N·cm~(-2)、9.50 g·100 g~(-1)和0.58 g·100 g~(-1),均高于其他2个采收期,早采或晚采都不适宜‘华硕’苹果采后果实品质的维持。【结论】采收期Ⅱ是‘华硕’苹果适宜的采收期,该采收期果实的淀粉染色等级为3～4级,乙烯释放速率为(10.65±0.60)μL·kg~(-1)·h~(-1),淀粉指数为(3.40±0.20),糖酸比为(10.57±0.14)。     

不同授粉品种对高原红富士着果率及品质的影响

针对昭通"红富士"苹果果形指数不高,偏斜果比率大,单产和优果率低,果实品质下降等问题,本研究以云贵高原昭通红富士品种为研究对象,选取昭通生产栽培品种"新红星""昭锦""双帅"和专用授粉品种"红玛瑙"等4个为红富士授粉品种,调查比较其花期、花粉萌发率,以及人工授粉对红富士苹果着果率、果实品质的影响。选用的4个授粉品种对红富士进行人工授粉后,其花序着果率及花朵着果率均明显高于自然授粉,花序着果率依次为新红星95.51%红玛瑙94.57%双帅92.13%昭锦92.11%;花朵着果率依次为红玛瑙87.08%双帅81.56%新红星76.92%昭锦75.66%;花粉萌发率昭锦74.5%红富士73.24%红玛瑙72.34%新红星69.94%双帅44.88%;红富士苹果偏斜度(DD)为自然授粉0.251新红星授粉0.179昭锦授粉0.168红玛瑙授粉0.154双帅授粉0.150,均达显著水平差异。试验结果表明,不同的授粉品种对红富士苹果果实的硬度、可溶性固形物含量、着色度、单果质量、果形指数等果实外观品质有显著性影响,差异水平因品种不同而有所不同。云南昭通红富士苹果栽培授粉品种配置不足,授粉受精不良是造成红富士苹果果实偏斜的重要原因之一;4个品种均可作为昭通红富士苹果授粉树,综合表现以专用苹果授粉品种红玛瑙最佳。     

2,4-滴丙酸对苹果树采前落果的控制与果实贮藏的效应

以90%2,4-DP结晶体、2,4,5-TP粉剂、10.8%2,4-DPNa,29%2,4-DPN(C_2H_2OH)_3配平平加乳化剂,稀释成所需浓度(清水对照含有相同浓度的平平加乳化剂),在果实采收前对新红星和元帅苹果进行全树喷布。结果表明,新红星在采前12、20、27天喷布20ppm2,4-DP或20ppm2,4,5-TP对控制采前落果有显著效果,都能显著的推迟采前落果时间、明显的减轻采前落果强度,对采收单果重和果实贮藏品质无不良影响,对果实贮藏中的合计损耗率有减少趋势。元帅在采前21天喷布一次20ppm2,4-DP,也显著的控制了采前落果,不影响单果重和果实品质,但同期喷布一次相同浓度的2,4-DPN(C_2H_2OH)_3或2,4-DPNa,则对控制采前落果无显著效果。2,4-DP可以用来代替2,4,5-TP作为苹果树的控制采前落果剂使用。     

新型1-MCP缓释粉剂对新红星苹果贮藏效果研究

以新红星苹果为试材,研究了不同浓度(0.8、1.0、1.5μL/L)0.03%1-MCP袋装缓释粉剂和对照药剂0.014%1-MCP缓释片剂对新红星苹果贮藏效果的影响。结果表明:1.5μL/L0.03%1-MCP袋装缓释粉剂对新红星苹果保鲜效果与常用1.0μL/L 0.014%1-MCP缓释片剂相当,在常温和冷藏条件下均能延缓果实硬度、可滴定酸含量和可溶性固形物含量下降,保持较好的果实品质,在冷藏条件下适宜贮藏期180天,20℃条件下适宜贮藏期40天;0.8、1.0μL/L 0.03%1-MCP袋装缓释粉剂对新红星苹果贮藏效果不如对照药剂。     

果形剂美果灵提高新红星和红富士苹果果形指数试验

以新红星和红富士苹果为试材,进行了美果灵对果实外观品质的影响试验,结果表明,于盛花初期喷与宝丰灵浓度相同（500倍液）的美果灵,对增进新红星和红富士苹果果形指数、增大果个和改善果实外观品质的效果与宝丰灵相同,而在保质期、使用费用等方面均明显优于宝丰灵。     

Benchmarking electrical methods for rapid estimation of root biomass

Background

To face climate change and subsequent rainfall instabilities, crop breeding strategies now include root traits phenotyping. Rapid estimation of root traits in controlled conditions can be achieved by using parallel electrical capacitance and its linear correlation with root dry mass. The aim of the present study was to improve robustness and efficiency of methods based on capacitance and other electrical variables, such as serial/parallel resistance, conductance, impedance or reactance. Using different electrode configurations and stem contact electrodes, we have measured the electrical impedance spectra of wheat plants grown in pots filled with three types of soil.

Results

For each configuration, parallel capacitance and other linearly independent electrical variables were computed and their quality as root dry mass estimator was evaluated by a ‘sensitivity score’ that we derived from Pearson’s correlation coefficient r and linear regression parameters. The highest sensitivity score was obtained by parallel capacitance at an alternating current frequency of 116 Hz in three-terminal configuration. Using a clamp, instead of a needle, as a stem electrode did not significantly affect the capacitance measurements. Finally, in handheld LCR meter equivalent conditions, capacitance had the highest sensitivity score and determination coefficient (r ² = 0.52) at 10 kHz frequency.

Conclusion

Our benchmarking of linear correlations between different electrical variables and root dry mass enables to determine more coherent practices for ensuring a sensitive and robust root dry mass estimation, including in handheld LCR meter conditions. This would enhance the value of electrical capacitance as a tool for screening crops in relation with root systems in breeding programs.

     

Water relations of lettuce. I. Internal physical aspects for two cultivars

Experiments were performed to assess physical aspects of internal water relations (reported in this paper), and the gas exchange properties as affected by drought (reported in a second paper). A Dutch cultivar (‘Amanda Plus’) and a French cultivar (‘Sucrine’) were used. Water was withheld from plants for 5 or 9 days, and the latter group was rewatered to observe the pattern of recovery 1 day after rewatering. Measurements were made of plant water potential (hygrometry), sap osmotic potential (hygrometry and cryoscopy), sap electrical conductivity, and plant relative water content (RWC). Hygrometry was found suitable for measurement of plant water and sap osmotic potentials, although equilibration time for the former parameter was long. With suspension of irrigation, all the parameters decreased except for the electrical conductivity which increased. Leaf water and osmotic potentials were lower in ‘Amanda Plus’ than in ‘Sucrine’, but pressure potential in the former was better maintained. Significant parabolic regressions existed for RWC and osmotic potential on plant water potential. The significant linear regressions of plant water and sap osmotic potentials on sap electrical conductivity were thought to provide easy methods for measurements of the 2 former parameters.     

复方新诺明对甜瓜种子萌发及活力的影响

以甜瓜种子为试材，通过SMZ-TMP预处理，研究了SMZ-TMP对甜瓜种子萌发质量及相关生理特性的作用。结果表明：较低浓度预处理明显促进了甜瓜种子萌发和生长，其萌发指数、发芽势、发芽率、根冠比和生物学产量等指标呈显著增长趋势，其中以0．4mg／L处理的效果极为显著。不同浓度的SMZ-TMP溶液均可降低甜瓜的相对电导率和MDA含量，但相对电导率和MDA含量的下降幅度随SMZ-TMP浓度的增加而减少。SMZ-TMP浸种使甜瓜萌芽的蛋白质和氨基酸总量都有显著提高。     

The influence of spatial configuration of green areas on microclimate and thermal comfort

It has been shown that the spatial configuration of a green area can strongly influence its cooling effect. However, the specific correlation has not been sufficiently studied. To systematically clarify the correlation between the spatial configuration and the cooling effect of green areas, 25 idealized scenarios are designed and simulated using the microclimate model ENVI-met. These 25 scenarios represent green areas with five different spatial configurations (integrated green area, sparse dotted green areas, dense dotted green areas, belt-shaped green areas parallel to wind direction, and belt-shaped green areas vertical to wind direction) and five vegetation types (trees with big canopies, trees with small canopies, hedges and shrubs, 50 cm grass, and 10 cm grass). The human thermal comfort of each scenario is evaluated by means of physiologically equivalent temperature (PET) using Rayman. The results reveal the influence of the fragmentation degree (quantified by the patch density and edge density), shape complexity (quantified by the land shape index), orientation of green belt, and vegetation type on the cooling effect of a green area. The spatial configuration and the vegetation type of green areas were found jointly affecting the efficiency of the green areas’ cooling effect. The highest cooling effect appears at 2 pm, reaching 6.3 K in the scenario of belt-shaped green areas parallel to the wind direction and with big canopy trees. The conclusions of this paper can provide suggestions for the climate-adaptive design and planning of urban green areas in the future.     

Light-emitting diodes as a radiation source for plants

Development of a more effective radiation source for use in plant-growing facilities would be of significant benefit for both research and commercial crop production applications. An array of light-emitting diodes (LEDs) that produce red radiation, supplemented with a photosynthetic photon flux (PPF) of 30 micromoles s-1 m-2 in the 400- to 500-nm spectral range from blue fluorescent lamps, was used effectively as a radiation source for growing plants. Growth of lettuce (Lactuca sativa L. Grand Rapids') plants maintained under the LED irradiation system at a total PPF of 325 micromoles s-1 m-2 for 21 days was equivalent to that reported in the literature for plants grown for the same time under cool-white fluorescent and incandescent radiation sources. Characteristics of the plants, such as leaf shape, color, and texture, were not different from those found with plants grown under cool-white fluorescent lamps. Estimations of the electrical energy conversion efficiency of a LED system for plant irradiation suggest that it may be as much as twice that published for fluorescent systems.     

脱锻炼期间白皮松针叶的电阻抗图谱参数和生理指标的相关性

 2007年3—5月, 对北京十三陵苗圃的北京蟒山、山西孝义和甘肃两当3个种源的9年生白皮松( Pinus bungeana Zucc. ) 针叶进行了电阻抗图谱( EIS) 分析, 测定其未冷冻针叶的EIS参数, 以及超氧化物歧化酶( SOD) 活性、过氧化物酶( POD) 活性、丙二醛(MDA) 含量、可溶性蛋白质、脯氨酸和干物质含量等生理指标的变化, 比较脱锻炼期间不同种源白皮松针叶的EIS参数和生理指标之间的相关性。结果表明: (1) 脱锻炼期间未冷冻针叶的EIS参数β和胞外电阻率r_e与针叶的脯氨酸含量之间存在负相关;细胞膜时间恒量τ_m与针叶的可溶性蛋白质含量存在正相关; (2) 胞内电阻率r_i与MDA, τ_m与干物质含量的变化趋势相同, 而r_e和β在脱锻炼前期与可溶性蛋白质含量的变化趋势类似; (3) 冷冻处理后用τ_m和r_e求出的抗寒性与脯氨酸含量相关。     

石油烃污染对三种灌木植物生理及叶绿素荧光参数的影响

通过盆栽试验,研究了不同浓度的石油烃胁迫对连翘、大花水桠木、紫穗槐生理及叶绿素荧光特性的影响。结果表明:在石油烃胁迫下,3种植物的MDA含量、电导率和叶绿素荧光参数与对照相比均有显著变化。3种植物的生理指标和叶绿素荧光参数的变化存在种间差异。石油烃含量在3 g/kg土和6 g/kg土2个处理中,连翘的生理指标和叶绿素荧光参数的变化幅度要小于大花水桠木和紫穗槐,对石油烃胁迫的抗性更强;石油烃含量在12 g/kg土时,3种植物的生长均受到最大抑制。     

Effects of day length on flowering and yield production of Salicornia and Sarcocornia species

Salicornia is a new vegetable crop that can be irrigated with highly saline water, even at salt concentrations equivalent to full-strength seawater. During leafy vegetable cultivation, the onset of the reproductive phase is an undesired phenomenon that reduces yield and quality and prevents year-round cultivation. Knowledge about the regulation of floral induction in the members of the tribe Salicornieae, however, is lacking. To establish year-round cultivation, we studied the flower induction of five Salicornia and two Sarcocornia varieties. Plants were grown under two day lengths, 13.5 h and 18 h, and harvested by a repetitive harvest regime. A 13.5-h day length prevented flower induction in the Israeli Salicornia varieties, but a longer day length was required to prevent flower induction in two species originating from more northern latitudes. The onset of the reproductive phase under suboptimal short day length conditions severely reduced vegetative growth and yields in Salicornia. In Sarcocornia, the repetitive harvest regime prevented flowering, making it a promising candidate for year-round cultivation. Irrigating the plants with full-strength seawater (electrical conductivity 48 dS m⁻¹) vs. water with moderate salinity (electrical conductivity 10 dS m⁻¹) did not change the general flowering pattern of the studied Salicornieae members.     

Changes in nutrient concentrations and leaf gas exchange parameters in banana plantlets under gradual soil moisture depletion

Changes in mineral nutrient concentration, growth, water status and gas exchange parameters were investigated in young banana plants (Musa acuminata cv. ‘Grand Nain’) subjected to gradual soil moisture diminution. Experiments were performed in glasshouse under controlled temperature, and water stress was imposed by ceasing irrigation for 62 days. The data showed a parallel decrease of leaf gas exchange parameters and soil moisture initiated few days after the imposition of water stress. However, the leaf relative water content (RWC) showed a minor decrease in response to drought. The onset of growth reduction evaluated as plant height, pseudostem circumference, number of newly emerged leaves, leaf area, and leaf and root biomass took place approximately between 34 and 40 days after the beginning of the stress period. In addition, drought did not modify nitrogen and phosphorus concentrations in foliar and root tissues; however, it increased potassium, calcium, magnesium, sodium and chloride in leaves, and only calcium, sodium and chloride in roots. Collectively, the data reveal that banana plants show a drought avoidance mechanism in response to water stress. After a prolonged drought period, leaf RWC was hardly reduced, while gas exchange and growth parameters were reduced drastically. Increasing leaf mineral concentration could have help to maintain leaf RWC due to osmotic adjustment mechanism.     

Mitigation of severe water stress by fruit thinning in ‘O’Henry’ peach: Implications for fruit quality

Fruit thinning can be used to relieve water stress in peach but it is not known how fruit quality will respond under water limited conditions. To elucidate this, we applied, over the growing seasons of 2003 and 2004, irrigation and fruit thinning treatments to ‘O’Henry’ peach at the onset of Stage III of fruit development. The treatments were full irrigation (FI) and no irrigation (NI) with each receiving three crop load levels: light, commercial and heavy. Fruit size and fruit skin colouration were lower in NI than in FI but the following were higher in NI fruit: firmness, juice titratable acidity and electrical conductivity, and concentrations of dry matter and soluble solids. All the quality parameters were significantly correlated with tree water status, expressed as midday stem water potential. NI fruit matured 5–10 days later than FI fruit. The increased dry matter concentration, juice acidity, and electrical conductivity in NI fruit were indicative of lower quality at harvest. Choosing a light crop load was not effective in improving NI fruit quality except for the size. Since fruit size is the most important fruit quality attribute, its increase might compensate for yield losses resulting from heavy fruit thinning. Nevertheless, when heavy thinning is performed for mitigation of water stress in Stage III, the overall fruit quality will suffer if severe water stress is inevitable because of shortage or lack of irrigation water.