二氧化氯对青椒采后生理和贮藏品质的影响

【目的】研究二氧化氯(ClO2)对青椒的保鲜作用，为青椒的贮藏提供新方法。【方法】用二氧化氯气体(0、5、10、20、50 mg·L-1)处理青椒，研究二氧化氯对青椒采后生理和贮藏品质的影响。【结果】5、10、20、50 mg·L-1的ClO2处理对青椒的腐烂有明显的抑制作用，40 d时其腐烂率均小于对照的50%；其中50 mg L-1的处理对腐烂的抑制效果最明显，贮藏到30 d时才有腐烂发生，40 d只有对照的1/4。20、50 mg L-1ClO2可显著抑制青椒的呼吸(P<0.05)，5、10 mg·L-1对呼吸的抑制作用不显著(P>0.05)。除50 mg·L-1外，5、10、20 mg L-1ClO2处理使MDA含量低于对照，但无显著差异(P>0.05)。5 mg·L-1的处理可以减缓青椒叶绿素的降解，10、20、50 mg·L-1的处理使青椒叶绿素含量低于对照，但无显著影响(P>0.05)。ClO2可保持青椒的营养成分，对青椒VC、可滴定酸和可溶性固形物含量有一定的保留作用；对青椒的风味无影响。【结论】二氧化氯可以有效延缓青椒的采后生理变化，保持青椒的品质。     

Selenium supplementation improves nutrient intake and digestibility,and mitigates CH4 emissions from sheep grazed on the mixed pasture of alfalfa and tall fescue

Low selenium (Se) in soil and forage can adversely affect on the quality of animal-derived foods, and hence on human health. Lambs grazed on mixed pastures of alfalfa (Medicago sativa) and tall fescue (Festuca arundinacea) were supplemented with five levels of Se [0, 3, 6, 9 and 12 µg/kg body weight (BW)]. The intake of dry matter (DM) and organic matter (OM) varied with the level of Se supplementation, with a peak at 6 µg Se per kg BW (p ≤ 0.05). Gross energy (GE) intake, digestive energy (DE) intake and metabolic energy (ME) intake were higher at 6 µg Se per kg BW than at other Se levels (p < 0.01); in addition, methane energy (CH₄-E) output was lower at 6 µg Se per kg BW. Supplementation with Se significantly increased nitrogen (N) intake, faecal N and urine N, for which the peak values were 20.2 g N/, 5.62 g N/day and 7.92 g N/day, respectively, at 6 µg Se per kg BW. Se intake, blood Se, faecal Se, urine Se and retained Se were negatively correlated with forage crude protein (CP) content (p < 0.001) but were positively correlated with the content of neutral detergent fibre (NDF) (p < 0.001) and acid detergent fibre (ADF) (p < 0.001). Thus, we recommend the addition of 6 µg Se per kg BW to sheep grazed on pastures in regions with low soil Se.     

不同生育期水稻干物质量与产量的关系研究

为明确不同生育期的干物重对粤晶丝苗2号、粤农丝苗、合美占3个水稻(Oryza sativa L.)品种的产量及产量构成因素的影响,设置了早造和晚造两次不同氮肥梯度随机区组栽培试验。结果表明,叶片干物质的分配比例在拔节孕穗期时最高,且其随着生育进程逐渐降低,在乳熟期达到最低值;茎干物质的分配比例在乳熟期降至最低;齐穗期的穗干物质分配比例不到20%,而乳熟期的穗干物质量将近占总干物质量的43%;早造和晚造水稻的结实率差异极显著,总干重差异显著,而穗数、每穗粒数、千粒重、产量差异不显著;齐穗期以后,结实率和千粒重均与干物重呈负相关,而叶干重与穗数呈显著正相关,且相关性较大,茎干重与各产量性状密切相关,总干重与产量呈正相关。水稻干物重是决定高产的重要因素。     

不同氮肥处理对荞麦干物质积累、农艺性状及产量的影响

为探索陕甘宁黄土高原地区栽培荞麦高产最适施氮量,以甜荞品种——西农9976为试验材料,设置4个氮肥水平,2016年施肥水平为:0 (N0)、45 (N45)、135 (N135)和225kg/hm2(N225);2017年施肥水平为:0(N0)、90(N90)、180(N180)和270kg/hm2(N270),比较不同施氮量下荞麦产量和主要农艺性状,分析叶绿素含量和各器官干物质积累的动态变化规律。试验结果表明,不同氮肥处理均能提高荞麦的株高、一级分枝数、二级分枝数、单株花簇数、千粒重和单株粒数,使其产量显著上升;荞麦主茎叶片的叶绿素含量(SPAD)随施氮量增加先上升后降低;荞麦各器官干物质积累量与施氮量呈正相关,但在苗期和初花期,荞麦各器官干物质积累量随施氮量增加呈抛物线。因此,生产上建议陕甘宁黄土高原地区荞麦生长过程中投入180kg/hm2的氮肥,且注重施氮比例及时期,以此达到最佳的生产效益。     

Compensatory Growth Responses During Reproductive Phase of Cowpea after Relief of Water Stress

Unpredictable drought affects growth and yield of dryland cowpea ( Vigna unguiculata [L.] Walp.) during rainy season. With the objective of identifying compensatory growth responses after relief of water stress, pot-grown plants (cv. C-752) were water-stressed at flowering, and physiological responses, short term dry matter partitioning upon relief of water stress, and productivity at maturity were studied. Water stress decreased, to varying degrees, leaf water potential, stomatal conductance, photosynthesis rate and transpiration rate. Recovery in assimilation lagged behind that in water relations. Assimilate supply seemed to be limiting early pod growth upon relief of water stress due to low photosynthesis rate, reduced leaf area per pod, and increased partitioning to leaf expansion. However, later pod growth was not limited by assimilate supply and final dry matter per pod was similar in both non-stressed and stress-affected plant. Cowpea exhibited the following growth responses during pod-fill stage upon relief of water stress: 1. increase in leaf area, 2. shift in dry matter partitioning in favour of leaf expansion, 3. extended green leaf duration, and 4. increase in pod number. These partially compensating physiological responses probably ensure reasonable productivity of dryland cowpea during rainy season.     

Sources of resistance to Verticillium wilt in Capsicum

Summary A total of 125 novel accessions of Capsicum annuum L. and Capsicum baccatum L. were screened for sources of resistance to Verticillium wilt (Verticillium dahliae Kleb). A soil infestation method with 2000 microsclerotia of V. dahliae per gram of planting medium, and a soil temperature of 25±3°C, identified 27 Capsicum accessions with resistance to Verticillium wilt. P.I. 215699 (a mixture of Capsicum baccatum var. microcarpum and Capsicum annuum), P.I. 535616 (Capsicum annuum), and P.I. 555614 (Capsicum annuum), had the lowest disease severity and the highest percentage of resistant plants.     

大豆籽粒干物质积累规律及与产量关系的研究

讨论了新疆高产春大豆品种新大豆1号和石大豆1号在不同种植密度及施肥水平处理下,籽粒干物质的积累规律及其与产量的关系.结果表明:不同品种、施肥水平、种植密度及冠层间的籽粒干物质积累均存在较大差异;植株中、上层籽粒干物质积累量与最后的产量形成关系密切,2个品种中层籽粒的干物质积累与产量形成达显著或极显著正相关.     

辣椒植株水浸液对辣椒和番茄种子萌发的自毒作用

采用室内生物测定的方法,研究了辣椒全株、根、茎、叶水浸液的化感效应.结果表明,辣椒全株、根、茎、叶水浸液对辣椒和番茄种子萌发的影响依供体部位、水浸液浓度和受体不同而有差异,辣椒植株水浸液对辣椒和番茄种子发芽存在自毒作用.辣椒植株全株、根、茎、叶水浸提液对辣椒和番茄种子发芽表现为抑制作用,并随着浓度的增大,抑制作用增强,这表明辣椒植株水浸液对辣椒和番茄种子发芽有较强的自毒作用.综合而言,辣椒全株、根、茎、叶水浸液对辣椒的自毒作用强弱依次为叶>根>茎>全株,对番茄的自毒作用强弱依次为叶>全株>根>茎.显示辣椒叶水浸液的自毒作用最强.     

白胡椒加工过程中的风味物质分析

为研究白胡椒加工过程中风味物质的变化,探讨异味物质的形成,以胡椒鲜果为原料,静水和换水浸泡2 种方式加工白胡椒,采用顶空固相微萃取和水蒸气蒸馏法萃取白胡椒粒风味物质,气相色谱-质谱联用仪检测分析浸泡3 天、6 天以及终极产品中风味物质组成及差异。白胡椒粒中共检测出167 种化合物,β-石竹烯相对含量最高,达到总组分的20.64%~28.31%,其次是柠檬烯,相对含量为6.89%~11.24%。在静水浸泡的白胡椒中检测到异臭物质3-甲基吲哚。白胡椒精油中共检测出31 种化合物,3-蒈烯(21.94%~24.64%)、β-石竹烯(17.51%~22.21%)、柠檬烯(18.04%~19.26%)、β-蒎烯(9.63%~10.67%)、α-蒎烯(4.46%~5.65%)、水芹烯(6.70%~7.53%)和月桂烯(3.44%~3.84%)等萜类化合物是白胡椒的主要风味物质。胡椒鲜果静水浸泡3天即能产生异臭味,而采用换水加工的白胡椒未检出异臭物质。     

辣椒病毒病检测技术和抗性鉴定技术研究进展

本文主要介绍了生物学方法、电镜观察、免疫学、分子生物学技术方面在植物病毒检测方面的特点和应用情况,同时介绍了辣椒材料抗性鉴定的方法和评价标准。