利用白色杜洛克×二花脸资源家系定位影响猪肉硬实度的QTL

为定位影响猪背最长肌和半膜肌硬实度的数量性状基因座(QTL),本研究测定了白色杜洛克×二花脸资源家系中490头F_2代猪的背最长肌和半膜肌硬实度,检测了3代个体在19条染色体上194个微卫星的基因型,并据此进行了QTL定位分析.共检测到9个QTLs,包括影响背最长肌硬实度的4个QTLs,分别位于SSC1、SSC2、SSC7和SSC10,其中SSC1和SSC7的QTLs达到1%基因组显著水平;影响半膜肌硬实度的5个QTLs分别位于SSC1、SSC7、SSC10、SSC12和SSC14,其中SSC7和SSC14的QTLs分别达到5%和1%基因组显著水平.     

EFFECT OF VARIOUS FOLIAR SPRAYS ON SOME FRUIT QUALITY ATTRIBUTES AND LEAF NUTRITIONAL STATUS OF THE PEACH CULTIVAR ‘ANDROSS’

The effect of various products applied as foliar sprays on some fruit quality attributes and leaf nutritional status of the peach cultivar ‘Andross’ for a three year period is reported. Foliar application of all calcium (Ca) products plus boron (B), did not affect mean fruit weight compared to the control. Application of profical plus calcium phosphite plus power 7-B resulted in an increase of flesh firmness. Low flesh firmness was measured at the potassium nitrate (KNO₃) and Chelan-K treatments. Foliar application of all Ca and K products did not alter significantly total soluble solids, total titratable acidity, and length and width of pits in comparison to the control. The highest amount of compact pits (without visual split) for the three year period was measured after foliar application of silene-K. Profical plus calcium phosphite plus power 7-B, and calcium chloride (CaCl₂) plus power 7-B gave also good results for the three years. Foliar application of agriphos, chelan-K, silene-K, and KNO₃ resulted in an increase of K concentration of leaves compared to the control. Foliar application of CaCl₂, bcazin, power-Ca, profical and calcium phosphite plus profical resulted in an increase of Ca concentration of leaves compared to the control for all the years. The efficacy of the foliar sprays varied from year to year indicating the influence of the climatic conditions on tree nutrition.     

Nitrogen and Potassium Fertilization Affect Apple Fruit Quality in Southern Brazil

Abstract

Nitrogen (N) and potassium (K) are usually found in higher concentrations than other macronutrients in apple (Malus x domestica Borkh) fruits and are most frequently associated with changes in fruit quality. The aim of this article was to evaluate the effects of N and K fertilization on some fruit quality attributes of Fuji apple. The experiment was conducted at São Joaquim, State of Santa Catarina, Brazil, during 2004 and 2005. A factorial design was used with N and K annual fertilizer rates (0, 50, 100, and 200 kg ha^?1 of N and K₂O) replicated in three orchards. Fifteen days prior to harvest, three fruit samples were collected from each treatment and site. One sample was used for total soluble solid content (TSS), titratable acidity, pulp firmness, and fruit color parameter analyses, and the other samples were refrigerated in a conventional atmosphere for 3 and 6 months for subsequent determination of fruit quality. Nitrogen fertilization negatively affected fruit color, flesh firmness, and TSS content. These same variables were positively affected by K fertilization, except for flesh firmness.     

Possible implication of metalloproteinases in post-mortem tenderization of fish muscle

ABSTRACT: It is suspected that the proteolytic breakdown of extracellular matrix proteins is responsible for the postmortem tenderization of fish muscle during chilled storage. In order to identify the type(s) of proteinases involved in this phenomenon, the effect of proteinase inhibitors, EDTA (ethylenediamine tetraacetic acid), 1,10-phenanthroline, ρ-APMSF [(ρ-amidinophenyl) methanesulfonyl fluoride hydrochloride] and E-64 [ L - trans -epoxysuccinyl-leucylamido-(4-guanidinobutane)] on tenderization was investigated by using Japanese flounder. Proteinase inhibitor solution was injected into a blood vessel in a caudal portion of live flounder and the firmness of muscle was then evaluated as a shear force value at 0 h and 6 h after death. Metalloproteinase inhibitors, EDTA and 1,10-phenanthroline, significantly suppressed postmortem tenderization. These findings suggest that metalloproteinases are candidates for proteinases involved in the postmortem tenderization of fish muscles. Although not significantly, p -APMSF, a serine proteinase inhibitor, partially suppressed muscle tenderization, which suggests that serine proteinases are also implicated in postmortem tenderization. A cysteine proteinase inhibitor, E-64, showed no effect, suggesting that cysteine proteinases are not involved.     

不同裂果易感性石榴品种果皮质构特性分析与显微结构观测

以不同裂果程度的4个石榴品种（‘大青皮甜’‘岗榴’‘秋艳’‘黑金刚’）为试验材料,利用质构仪和显微镜观察测定其果皮质构特性和组织结构特点,解析果皮质构特性和细胞结构在石榴裂果中的作用,为防治石榴裂果提供理论依据。结果表明,采用质构仪测定石榴果皮内外侧破裂力,其外侧破裂力为1050.28~1927.24 g,内侧破裂力为686.01~1526.31 g,同一品种果皮外侧破裂力显著高于内侧破裂力,内外侧破裂力比越小的品种越不易发生裂果;并且果皮紧实度越大越容易产生裂果,其中,‘秋艳’果皮紧实度最低,为85.20 g,石榴果皮紧实度与其裂果性呈负相关的关系;4个石榴品种果皮表层细胞厚度为2.23×10^-2~3.58×10^-2mm,表层细胞面积为6.76×10^-4~10.30×10^-4mm²,表层细胞厚度和面积与石榴品种裂果性无明显相关性;裂果与果皮厚度呈明显的负相关性,即果皮厚的品种容易裂果,果皮薄的品种抗裂果。     

Effect of low-pressure storage on the quality of green capsicums (Capsicum annum L.)

Green capsicums (Capsicum annum L.) were stored under low pressure (4 kPa) at 10°C for 5 and 11 days with 100% RH. The results showed that the incidence of stem decay under low-pressure storage for 5 and 11 days and storage at ambient atmosphere at 20°C for 3 days was lower compared to fruits that were stored at regular atmosphere at 10°C. Fruit that had been stored at low pressure at 10°C had no symptoms of flesh rots for up to 11 days, whilst fruit which had been stored at regular atmosphere at 10°C had 6% flesh rots after 11 days storage at 10°C.There was no difference in flesh firmness and colour retention between fruits stored at low pressure and regular pressure at 10°C. Capsicums stored at low pressure had higher overall acceptability compared to fruit that were stored at regular atmosphere at 10°C. These results demonstrate the potential of low pressure storage as an effective technique to manage capsicum fruit quality, however, there was no additional benefit when fruits were stored at low pressure for more than 5 days.     

香蕉采后果肉硬度与淀粉代谢变化

为了弄清楚香蕉采后果实硬度与淀粉代谢的变化规律及相关性,以‘巴西’蕉(Musa sp. ‘Brazil’)果肉为试材,对香蕉采后果实淀粉代谢与果肉硬度变化进行分析。结果表明,贮藏过程中,果肉硬度逐渐下降,总淀粉含量呈下降趋势,总淀粉酶活性呈上升趋势,α-淀粉酶和β-淀粉酶活性呈先增后减的单峰型变化;相关性分析发现,香蕉采后果肉硬度下降与总淀粉含量变化呈极显著正相关,与总淀粉酶活性变化呈极显著负相关,与α-淀粉酶和β-淀粉酶活性变化相关性不显著。香蕉采后果肉硬度下降可能主要涉及到总淀粉含量的下降和总淀粉酶活性的上升。     

Key minerals influencing apple quality in Chinese orchard identified by nutritional diagnosis of leaf and soil analysis

We investigated the correlation between leaf/soil minerals and fruit quality in apple trees grown in orchards,with the ultimate goal of improving the latter.Leaf mineral nutrients;soil nutrients in the 0-20,20-40,and 40-60 cm layers;and fruit quality traits in 32 apple orchards in China were monitored for 2 years.Significant factors associated with fruit quality were identified via correlation analysis.An analysis of leaf data revealed that leaf nitrogen(N) and leaf magnesium(Mg) levels were extremely high in 75 and 89%of the orchards,respectively.In the Bohai Gulf region,94%of the orchards showed significantly higher values than the standard.The soil pH values of the orchards in eastern China like eastern Shandong or Liaoning were lower than 7.0,while the pH values in the Loess Plateau of northwestern China like Shaanxi were much higher than 7.Soil alkali-hydrolyzable N levels in 47%of the orchards were lower than the optimal level of 70 mg kg~(-1).Generally,the soil alkali-hydrolyzable N levels of orchards in the Bohai Gulf region were significantly higher than those in the Loess Plateau region.The available P levels in the orchards of the Bohai Gulf region were up to three times higher than those of the Loess Plateau region.However,although the available potassium(K) in most orchards was sufficient(51.39-309.94 mg kg~(-1)),leaf K content in 73%of the orchards was low,possibly due to fruit bagging or fruit overload.Approximately 63%of the orchards in Shandong and 29%of the orchards in Shannxi showed leaf Fe deficiencies.In the Loess Plateau,most orchards showed high leaf Ca levels,a strong correlation was observed between leaf and soil phosphorus/potassium(P/K)content and fruit organic acid content.The amounts of fruit soluble sugar or fructose were positively correlated with soil calcium/potassium(Ca/K) levels and leaf calcium/boron(Ca/B) levels in most orchards.The excessive leaf N levels caused by the extensive application of N fertilizers had a negative effect on fruit quality in most apple orchards in China.P,K,Ca,and B were key minerals associated with fruit quality.     

不同条件下美锦桃果实硬度变化规律研究

研究了美锦桃在树上、常温和冷藏条件下果实硬度的变化规律。结果表明:美锦桃果实在室温、冷藏及树上,其果实硬度均呈下降趋势,其中,冷藏条件下果实硬度下降最慢,室温条件下果实硬度下降最快。美锦桃为高硬度、长采收期和长货架期品种。美锦桃在树上采收持续期可达30 d,在室温条件下贮藏期为10 d以上,冷藏条件下可贮藏30 d以上。     

草地切根施肥补播开沟装置的设计与试验

为克服草地土壤坚实度高、残茬根系量大带来的开沟问题,在草地切根改良的基础上实现施肥补播,采用破土刀齿破茬-种沟双圆盘开沟器开沟覆土-肥沟双圆盘开沟器压土成沟并覆盖种沟的工艺构建种床与肥床,设计分层交错式覆土开沟装置,建立种沟与肥沟双圆盘开沟器需满足的参数关系。基于土壤扰动造成土壤坚实度下降理论,通过对比试验,确定种沟开沟器距切根沟缝的距离对土壤坚实度的影响,得到将种沟开沟器布置在距离切根沟20mm处,可使开沟器入土处的土壤坚实度下降62%。将分层交错式覆土开沟装置应用于9QFB-2.4型破土切根施肥补播复式作业机,田间试验结果表明:该装置能够实现稳定开沟,形成深47.3mm、宽29.1mm的肥床与深44.7mm、宽19.5mm的种床,施肥和播种深度合格率分别达到80%和83%,且对土壤的扰动程度小于14%,有利于草场植被的保护。