Effect of Low Temperature Storage on Seed Germination and Seedling Growth of Dragon Fruit

In order to explore the best storage temperature and storage period of dragon fruit seeds,with the constant-humidity germplasm cold storage of Guangxi Academy of Agricultural Sciences as a platform and storage temperature as an environmental factor,the germination characteristics of dragon fruit seeds and seedling growth characteristics under low temperature storage(8,4,-1,-10℃)and room temperature storage(25-30℃)over time were explored.The results showed that with the extension of the storage time,the seed germination rates,germination index,healthy seedling rates,seedling heights and fresh weights of 10 seedlings of the three dragon fruit varieties showed basically the same trends,showing a downward trend.After 367 d of cold storage,the germination rate decreased from 100%to 92.33%-98.00%,and the room temperature treatments decreased to 54.00%-86.30%;and the healthy seedling rates of cold-stored seeds decreased from 96.33%-98.00%to 77.33%-97.3%,and the values of the room temperature treatments dropped to 12.00%-68.33%.The germination rates,germination index,healthy seedling rates and seedling heights of the three dragon fruit varieties stored at low temperatures were basically significantly higher than those of the room temperature treatments within 367 d of storage.The germination rates of the three varieties stored at 8℃had no significant differences from other low temperature treatments,but the germination index was significantly lower than other low temperature treatments at 367 d.It showed that low temperature storage at-10-8℃could significantly prolong the vigor and storage time of dragon fruit seeds.Considering cost and other factors,it is better to store dragon fruit seeds in a dry environment at 4℃.The seeds stored at 4℃for 1 year showed a germination rate maintained over 90%and a healthy seedling rate over 85%.

Rice seed storage proteins:Biosynthetic pathways and the effects of environmental factors

Rice(Oryza sativa L.)is the most important food crop for at least half of the world’s population.Due to improved living standards,the cultivation of high-quality rice for different purposes and markets has become a major goal.Rice quality is determined by the presence of many nutritional components,including seed storage proteins(SSPs),which are the second most abundant nutrient components of rice grains after starch.Rice SSP biosynthesis requires the participation of multiple organelles and is influenced by the external environment,making it challenging to understand the molecular details of SSP biosynthesis and improve rice protein quality.In this review,we highlight the current knowledge of rice SSP biosynthesis,including a detailed description of the key molecules involved in rice SSP biosynthetic processes and the major environmental factors affecting SSP biosynthesis.The effects of these factors on SSP accumulation and their contribution to rice quality are also discussed based on recent findings.This recent knowledge suggests not only new research directions for exploring rice SSP biosynthesis but also innovative strategies for breeding high-quality rice varieties.

Study on Seed Vigor of Rice Photo-ThermoSensitive Genic Male Sterile(PTGMS) Line with Low Temperature Storage

To explore the change rule of seed vigor and seed application technology of rice PTGMS lines with low temperature storage,Zhun S,Y58S,Feng S and Guangzhan 63-4S stored in the seed bank with the temperature of 8-10 ℃ and with the relative humidity of 55% for different years were used as the materials to study the properties of seed vigor,growth and development in the field, etc. The re- sults showed that the germination potential, germination rate, germination index and vigor index of rice PTGMS lines seeds showed downward trends as the time of low temperature storage prolonged,and all of the germination rates of the seeds within five years were over 60%. The conductivity in the soaked solution of seeds was significantly increased with the prolonged low temperature storage time. Seedling rate,root length,white root number,base stem width and seedling dry weight of seeds showed downward trends as the time of low temperature storage prolonged. There was no significant difference between two integral seedling qualities of seeds within 4-6 years in low temperature storage. Compared with the germination rate of low temperature storage seeds soaking for 6,12 and 24 h,the appropriate soak time of long time low temperature storage or low vigor seeds was 12 h. A serious natural aging phenomenon occurred in low temperature storage seeds after out of the storage. The germination rate of seeds placed under natural condition for 50 d decreased obviously. The duration from seeding to heading of Zhun S,Y58S and Feng S shortened as the time of low temperature storage prolonged, while the vari- ation of panicle duration of all PTGMS lines was not obvious. In conclusion, rice PTGMS line seeds with low temperature storage in 5 years could still be used nor- mally. However.seeds after low temperature storage should be sowed as soon as possible, and the soaking time of low vigor seeds should be shortened,and the possibility that the decreased duration from seeding to heading should also be con- sidered.

Effects of Different Storage Conditions on Physiological and Biochemical Characteristics of Polygala tenuifolia Willd. Seeds

[Objectives] Taking Polygala tenuifolia Willd. seeds as experimental material, the changes of physiological and biochemical characteristics of seeds under different storage temperatures and seed moisture contents were studied. [Methods] The seeds of P. tenuifolia Willd. with moisture contents of 3%, 5% and 15% were stored at-10 ℃, 0 ℃, 20 ℃ and 36 ℃, respectively, and the storage time was one year. The physiological and biochemical characteristics of the seeds, such as conductivity, SOD activity, POD activity, and soluble sugar content were studied.[Results] After one-year storage, as the storage temperature and seed moisture content increased, the relative conductivity, MDA content and soluble sugar content of P. tenuifolia Willd. seeds increased, while the SOD activity, POD activity, and protein content declined. This phenomenon was most obvious in the P. tenuifolia Willd. seeds with moisture content of 15%. [Conclusions] This study will provide reference for seed storage of medicinal plants.

Experiments on rockburst proneness of pre-heated granite at different temperatures: Insights from energy storage, dissipation and surplus

Many underground engineering projects show that rockburst can occur in rocks at great depth and high temperature, and temperature is a critical factor affecting the intensity of rockburst. In general, temperature can affect the energy storage, dissipation, and surplus in rock. To explore the influence of temperature on the energy storage and dissipation characteristics and rockburst proneness, the present study has carried out a range of the uniaxial compression(UC) and single-cyclic loading-unloading uniaxial compression(SCLUC) tests on pre-heated granite specimens at 20℃-700℃. The results demonstrate that the rockburst proneness of pre-heated granite initially increases and subsequently decreases with the increase of temperature. The temperature of 300℃ has been found to be the threshold for rockburst proneness. Meanwhile, it is found that the elastic strain energy density increases linearly with the total input strain energy density for the pre-heated granites, confirming that the linear energy property of granite has not been altered by temperature. According to this inherent property, the peak elastic strain energy of pre-heated granites can be calculated accurately. On this basis, utilising the residual elastic energy index, the rockburst proneness of pre-heated granite can be determined quantitatively. The obtained results from high to low are: 317.9 k J/m^(3)(300℃), 264.1 k J/m^(3)(100℃), 260.6 k J/m^(3)(20℃), 235.5 k J/m^(3)(500℃), 158.9 k J/m^(3)(700℃), which are consistent with the intensity of actual rockburst for specimens. In addition, the relationship between temperature and energy storage capacity(ESC) of granite was discussed, revealing that high temperature impairs ESC of rocks, which is essential for reducing the rockburst proneness. This study provides some new insights into the rockburst proneness evaluation in high-temperature rock engineering.

A Study of Estimating the Safe Storage Life, Self-accelerating Decomposition Temperature and Critical Temperature of Thermal Explosion of Double-base Propellant Using Isothermal and Non-isothermal Decomposition Behaviours

A method of estimating the safe storage life （τ）, self-accelerating decomposition temperature （TsADT） and critical temperature of thermal explosion （Tb） of double-base propellant using isothermal and non-isothermal decomposition behaviours is presented. For double-base propellant composed of 56±1wt% of nitrocellulose （NC）, 27±0.5wt% of nitroglycerine （NG）, 8.15±0.15wt% of dinitrotoluene （DNT）, 2.5±0.1wt% of methyl centralite, 5.0±0.15wt% of catalyst and 1.0±0.1wt% of other, the values of r of 49.4 years at 40℃, of TSAOT of 151.35℃ and of Tb of 163.01℃ were obtained.

Effect of matrix thermal properties on laser-induced plasma

The matrix thermal properties have an important impact on laser-induced plasma,as the thermal effect dominates the interaction between ns-pulsed laser and matter,especially in metals.We used a series of pure metals and aluminum alloys to measure plasma temperature and electron density through laser-induced breakdown spectroscopy,in order to investigate the effect of matrix thermal properties on laser-induced plasma.In pure metals,a significant negative linear correlation was observed between the matrix thermal storage coefficient and plasma temperature,while a weak correlation was observed with electron density.The results indicate that metals with low thermal conductivity or specific heat capacity require less laser energy for thermal diffusion or melting and evaporation,resulting in higher ablation rates and higher plasma temperatures.However,considering ionization energy,thermal effects may be a secondary factor affecting electron density.The experiment of aluminum alloy further confirms the influence of thermal conductivity on plasma temperature and its mechanism explanation.

贮藏温度对火棘鲜果采后生理及功效活性成分的影响

以重庆彭水野生火棘鲜果为试材,研究贮藏温度对火棘功效活性成分原花青素、黄酮、总酚和VC含量的影响,分析相关抗性酶超氧化物歧化酶(superoxide dismutase,SOD)、苯丙氨酸解氨酶(shenylalanine ammonia lyase,PAL)活性和次生代谢产物丙二醛(malondialdehyde,MDA)含量及腐损率变化趋势。结果表明:-5、-3、-1、1、3、5℃贮藏60 d原花青素保持率分别是初始含量的72.97%、65.43%、48.12%、29.76%、21.33%和19.22%;黄酮保持率分别为77.25%、76.27%、72.01%、60.39%、56.96%和35.19%;总酚保持率分别为83.66%、82.61%、62.80%、55.69%、48.51%和43.11%;VC保持率分别为87.17%、86.43%、75.46%、54.83%、36.06%和24.35%;SOD活性保持率分别为81.56%、79.78%、66.32%、27.86%、15.83%和11.25%;PAL活性保持率分别为57.43%、50.05%、42.00%、19.69%、15.62%和14.12%;MDA累积程度与初始含量相比,分别为2.19、2.59、4.51、6.52、7.52倍和8.54倍;腐损率与5℃贮藏60 d相比,分别低88.10%、87.94%、81.09%、54.25%和12.53%。-5、-3℃贮藏与5、3、1、-1℃贮藏相比均可有效保持原有功效成分、降低腐损率、减少MDA累积程度、保持较高SOD和PAL活性,但-5℃和-3℃贮藏差异不显著,-3℃可作为优选贮藏温度。

聚氨酯型固-固相变储能材料对沥青调温效果的影响研究

聚氨酯型固-固相变储能材料可以有效提高沥青的相变储能能力,从而在调节路面温度的同时,减小温度波动。基于上述背景,针对聚氨酯型固-固相变储能材料对沥青调温效果的影响展开研究。确定相变材料的分类标准,并分别研究其储能原理及具体应用情况,完成对聚氨酯型固-固相变储能材料特性的分析。在此基础上,定义周期性储热边界条件,根据沥青调温过程中内聚能密度的变化形式,推导相变储能材料的能量变化规律,从而确定聚氨酯型固-固相变储能材料对沥青调温效果的影响能力。

基于温度循环加速退化试验的光纤连接器寿命评估

针对光纤连接器在温度交替变化下寿命评估难的问题,提出一种基于修正Coffin-Manson模型的寿命评估方法。首先,分析了光纤连接器失效模式、机理。接着,开展光纤连接器多个加速应力水平下的温度循环加速退化试验,基于插入损耗加速退化数据建立幂函数退化轨迹模型。然后,结合插入损耗的失效阈值,通过假设检验推导不同加速应力水平下光纤连接器的伪失效寿命。最后,引入修正Coffin-Manson加速模型,进而外推空间环境下光纤连接器寿命。本方法评估的某光纤连接器在实际应力水平下的寿命与实际寿命比较接近,验证了修正Coffin-Manson模型方法对光纤连接器寿命评估的有效性和可行性。

新疆椒麻鸡腿的品质变化及货架期预测

为了探究新疆椒麻鸡腿贮藏期间品质变化并对其货架期进行预测。本文以新疆椒麻鸡腿为研究对象,以酸碱度值(Potential of hydrogen,pH)、色泽、硫代巴比妥酸值(Thiobarbituric acid reactive substances,TBARS)、挥发性盐基氮(Total volatile basic nitrogen,TVB-N)、菌落总数、大肠菌群及感官品质为评价指标,利用加速性破坏实验,研究不同贮藏温度(35℃和45℃)下椒麻鸡腿的品质变化,以感官得分70分或菌落总数接近国家标准作为货架期终点,并预测出常温(25℃)下椒麻鸡腿的货架期。结果表明:不同贮藏温度下的椒麻鸡腿随着贮藏时间的不断延长,pH呈先下降后上升趋势,L^(*)值整体呈下降趋势,而a^(*)值、b^(*)值、TBARS值、TVB-N含量和菌落总数均呈上升趋势,感官评分则不断下降,在贮藏期且45℃的变化速率高于35℃,在35℃贮藏温度下,理论货架期为24 d,在45℃贮藏温度下,理论货架期为9 d,在货架期终点样品品质出现不可接受的损失。根据Q_(10)模型计算出Q_(10)=2.6,根据模型预测出常温(25℃)条件下理论货架期为62 d。

不同保鲜处理对青皮核桃贮藏品质的影响

为探究不同保鲜处理对青皮核桃贮藏效果的影响,该研究以青皮核桃为试验材料,采用4种不同保鲜方法进行处理:0℃冷水浸泡5 min、150 mg/L ClO_(2)浸泡20 min、100 mg/L赤霉素浸泡20 min和赤霉素(100 mg/L)+咪鲜胺(有效成分含量450 g/L)混合处理20 min,以不做处理的青皮核桃为对照,在0±0.3℃的低温条件下贮藏,研究其贮藏期间褐变指数、水分含量、色差、呼吸强度、硬度、叶绿素含量、丙二醛(malondialdehyde,MDA)含量、多酚氧化酶(polyphenol oxidase,PPO)和过氧化物酶(peroxidase,POD)活性,总酚和总黄酮含量。结果表明,在贮藏期间,处理组青皮核桃与对照组相比,处理组显著(P<0.05)延缓了其水分含量的降低和色差的变化,延缓褐变指数、呼吸强度和PPO活性的上升,抑制了硬度、叶绿素、总酚、总黄酮含量的下降,降低了贮藏期MDA的生成量,更好的保持POD活性。由试验可知,赤霉素+咪鲜胺处理的青皮核桃水分含量、硬度、叶绿素含量、总酚和总黄酮含量最高,褐变指数和色差上升最缓慢,呼吸强度最低,丙二醛含量和PPO、POD活性最低,保鲜效果最佳。

冰温贮藏结合生物保鲜剂对虹鳟鱼肉品质特性影响的研究

虹鳟鱼肉质鲜美,营养丰富,是我国重要的经济鱼类,但其在贮藏、运输、销售过程中极易发生腐败变质,影响食用价值。为研究虹鳟鱼在贮藏过程中的高效保鲜方案,延长货架期,以4℃冷藏为对照,通过测定不同实验工况下鱼肉的汁液流失率、pH值和挥发性盐基氮(TVB-N)等指标,研究0℃冰温贮藏以及0℃冰温贮藏+生物保鲜剂(壳聚糖、茶多酚、柠檬汁质量分数分别为1.75%、0.25%、4.98%)对鱼肉品质的影响。结果表明:0℃冰温贮藏组的各项指标及随时间的上升幅度均优于4℃冷藏,可有效减缓虹鳟鱼肉的腐败进程;第12 d时,4℃冷藏的pH值和TVB-N值分别为6.86和51.89 mg/100 g, 0℃冰温贮藏的pH值和TVB-N值分别为6.56和31.82 mg/100 g,而0℃冰温贮藏+生物保鲜剂组的pH值、TVB-N值仅为6.32和16.96 mg/100 g,该方案对虹鳟鱼肉的保鲜效果更佳,可有效延长其货架期。

超快速冷却对生鲜羊肉中糖酵解酶表达量的影响

以不同降温速率处理和不同温度条件下贮藏的羊背最长肌为样品,比较分析宰后不同时间生鲜羊肉的pH值、葡萄糖含量、糖酵解潜力和5个糖酵解酶的表达量,明确超快速冷却过程中两个环节对糖酵解的影响,从蛋白质表达量的角度完善超快速冷却对糖酵解速率的调控机制。结果显示,超快速冷却显著延缓了pH值下降和糖酵解速率上升,上调了醛缩酶、糖原磷酸化酶和磷酸丙糖异构酶的表达量,下调了磷酸果糖激酶(phosphofructokinase,PFKM)和磷酸甘油酸激酶(phosphoglycerate kinase,PGK)的表达量。降温处理后采用冷藏和冰温贮藏通过抑制PGK的表达量延缓糖酵解,不改变超快速冷却的作用。不同温度条件下,PFKM的表达量与糖酵解速率呈正相关。不同代谢酶对温度变化的响应不同,超快速冷却通过改变代谢酶的表达量影响能量供需,其中高表达量的PFKM与快速糖酵解相关,可以视为超快速冷却过程中的关键酶。

淀粉魔芋豆腐的品质变化及货架期预测

为研究绿豆淀粉魔芋豆腐在贮藏期内的品质变化及货架期预测,采用两种不同类型的灭菌方式处理纯魔芋豆腐(K0)和绿豆淀粉魔芋豆腐(KL),以感官评分、硬度、持水力、水分含量、p H值、菌落总数为评价指标,利用货架期加速试验,研究不同贮藏温度(27、37、47℃)下绿豆淀粉魔芋豆腐的品质变化,以感官评分小于60或菌落总数超过国家标准为货架期终点,预测低温(5℃)和室温(23℃)下绿豆淀粉魔芋豆腐的货架期。结果表明:经煮沸灭菌后,随着贮藏时间的延长,绿豆淀粉魔芋豆腐的菌落总数呈上升趋势,而感官评分、硬度值、持水力、水分含量、p H值呈现出先上升后下降的趋势。在贮藏期内,K0在27、37、47℃的货架期终点为16、12、8 d,KL的货架期终点分别为28、24、16 d。经高压蒸汽灭菌后,随着贮藏时间的延长,绿豆淀粉魔芋豆腐的菌落总数始终达标,而感官评分、硬度值、持水力、水分含量、p H值呈现出先上升后下降的趋势,K0在不同温度下的货架期分别是84、76、68 d,KL的货架期分别为100、92、80 d。经Q_(10)预测模型可知,煮沸灭菌后的K0、KL贮藏在室温(23℃)条件下的货架期分别是21、42 d,贮藏在低温(5℃)条件下的货架期分别是44、88 d。高压蒸汽灭菌后的K0、KL贮藏在室温(23℃)条件下的货架期分别是89、112 d,贮藏在低温(5℃)条件下的货架期分别是108、144 d。由此可知高压蒸汽灭菌效果更好,灭菌产品货架期更长,且绿豆淀粉魔芋豆腐货架期更长。

高压气瓶非接触压力测量系统设计

常规状态下气瓶压力测量,在气瓶出口管路上开口进行引压测量,对于高压气瓶在长期贮存的情况下,开口引压存在开口部位压力泄漏的隐患;为克服气瓶开口引压泄漏问题,对气瓶非接触压力测量系统进行分析研究,基于气瓶壁在压力下产生形变的情况,通过对气瓶壁进行应变测量关键技术,建立气瓶壁的应变量与内部压力之间的关系计算模型,经多次实验验证,积累不同温度及压力下的相关数据参数,运用数据模型拟合具有温度补偿的压力计算公式,通过编程写进便携式测试仪,实现对高压气瓶在不接触介质的情况下非接触压力测量的目的,并满足了气瓶在高压下进行长期贮存时随机测量的应用需求。

不同贮藏方式对地果果实保鲜效果的影响

该研究以地果成熟的果实为材料,用柠檬酸、抗坏血酸、L-半胱氨酸和NaCl对果实进行浸泡处理,以果实褐变度为评价指标,基于正交试验筛选出最佳复合保鲜液配方,并在不同温度(25、15、4℃)条件下进行开放式和密封式贮藏,通过测定贮藏期间果实的形态、色度、硬度、质量损失率、皱腐率及生理生化指标,比较最佳复合保鲜液在不同贮藏方式及温度下对地果果实贮藏品质的影响。结果表明:地果成熟果实的最佳复合保鲜液配方为1.5%柠檬酸+0.5%抗坏血酸+0.15%L-半胱氨酸+0.5%NaCl,并且最佳复合保鲜液处理后进行密封式低温贮藏能显著抑制地果果实皱腐率、质量损失率和丙二醛(malondialdehyde,MDA)含量的上升,减缓果实硬度、果皮色差值、可溶性固形物(total soluble solids,TSS)含量、可滴定酸(titratable acidity,TA)含量和维生素C(vitamin C,VC)含量的下降。综合分析,最佳复合保鲜液浸泡处理后,低温密封式贮藏可以有效延长地果成熟果实的贮藏期,并能维持较好的贮藏品质,以4℃密闭式贮藏的保鲜效果最佳。

含水层储层多能互补系统的采热效果数值模拟分析

构建了一种基于含水层储层的多能互补系统,分析了含水层多能互补系统的地层温度响应特征和产水井温度变化规律,探讨了回灌温度、井底压差和井间距对产水井温度的影响规律,最后通过响应面法分析了各因素的显著性。结果表明,该系统可有效延长地热井使用年限,并实现将波动性能量通过地层内的热量交换和平衡最终输出稳定能量的功能。提高回灌温度可减缓产水井温度的下降幅度,增大井底压差会缩短平衡产热时间并加速产水井温度下降,增大井间距导致产水井稳定时间延长并减缓产水井温度下降幅度。采用响应面分析方法,分析出4个因素对产水井水温影响的主次顺序为井间距>井底压差>回灌温度>使用年限,交互作用中影响最大的为回灌温度与井间距。

三峡水库水面蒸发年内滞后效应分析

水面蒸发在季节变化上相比净辐射等气象要素的相位延迟反映了水体储热对水面蒸发的影响,量化这一对气象要素波动的滞后响应对理解和估算深水水库(湖泊)蒸发非常重要。三峡水库等河道型深水水库的水位和面积具有显著周期性变动,使得其水面蒸发的响应模式更为复杂,而目前对其认识非常薄弱。本文利用2013年8月—2020年7月三峡水库巴东站水面蒸发场和陆面蒸发场的蒸发和气象观测数据,分析了水面蒸发的季节变化及其年内滞后效应。结果表明:水面蒸发场蒸发量在年内的8和12月呈现双峰变化,与只有8月单峰值的陆面蒸发场蒸发量显著不同。水面蒸发场蒸发量相对净辐射、平均气温和水面温度分别存在4、3和2个月的滞后,而陆面蒸发场蒸发量相对滞后时间均在1个月以内;水面与陆面蒸发场相比,水温、蒸发量和水面与大气饱和差之间的滞后时间分别为1、3和4个月,而平均气温和净辐射之间不存在滞后。本文揭示出三峡水库巴东段水面蒸发年内滞后效应主要受到水库水温引起的水面与大气饱和差在季节上滞后的影响,需通过深入分析水温的时空变化来明确整个三峡水库的水面蒸发特征。

环境与荷载作用下大型钢筒仓力学性能研究进展

钢筒仓是工业、农业等领域不可缺少的储存装置。随着规模的不断扩大,大型钢筒仓的安全性、适用性、耐久性成为人们关注的重点,多位学者对钢筒仓展开了研究。文中综合分析了国内外对钢筒仓的研究现状,在储料作用方面,研究了储料静态侧压力,将规范结果同有限元计算结果进行对比,对储料的接触状态、温度、摩擦角、摩擦系数、本构模型选用,以及偏心卸料过程中的侧压力分布形式进行探讨;在太阳辐射及温度作用方面,对均匀温度作用下钢筒仓仓壁的应力应变及稳定性进行了评估,对太阳辐射作用下形成的不均匀温度场引入余弦分布的概念进行了模拟并深入探究;在地震作用方面,主要进行了有限元分析,输入不同地震波,并与规范计算结果相互比对,基于地震作用下储料作用对仓壁侧压力的影响进行研究。