Studies on Amylase and Degradation of Starch and Pigment of Tobacco Leaf During Process of Flue-Curing

The changes in the activity of amylase and amylase-isoenzyme and the degradation of starch and pigment of tobacco leaf during flue-curing were studied by using the electricheated flue-curing barn designed and made by the Henan Agricultural University. The temperature and humidity of the barn were controlled automatically. The results indicated that starch in tobacco leaf decreased rapidly and leveled off after 48h of cutting, in the meantime, the content of soluble sugar increased accordingly and reached a peak at the stage of color-fixing. Both of them had a rapid-changing stage in the first 36 hours of yellowing. The changes of starch and soluble sugar contents had highly significant negative-correlation at 1% level (rNC89=-0.8962**, rYY85=-0.9704**). The activity of amylase increased with the proceeding of curing and reached a peak after 36 hours of curing, then decreased. But the activity of amylase kept at a high level when the humidity of curing-environment was very low, even if the tobacco leaf had been dried. The rapid degradation of starch showed a significantly negative correlation with the increase of activity of amylase at 5 % level (rNC89=-0.8495*, rYY8*=-0.7839*). The degradation of starch and pigment had the same regulation and had highly significant correlation at 1% level (rNC89=0.9649**, rYY85=0.9428**). There were mainly three amylase-isoenzyme bands -A, B, C respectively, in tobacco leaf during flue curing. They were identified as α-AMY, -AMY, R-AMY, and the activity of β-AMY was the highest. The changes in amylase activity and contents of starch and pigment were affected by the tobacco leaf moisture and environmental humidity during curing.     

几种花卉常见侵染性病害的防治技术

<正>一、白粉病病菌主要侵染嫩芽、嫩叶、嫩梢、花蕾和花梗等处。刚染病时,受害部位出现褪绿斑点,日渐扩大,以后逐渐变成白色粉斑,受害叶和茎梢生长畸形并向上卷曲萎缩,整株花卉生长衰弱,开花小而少或花有畸形。发病后期,白色粉斑逐渐变成大小不等的褐色或黑色斑点,叶片变黄、卷曲而最终脱落。这类病菌随气流传播,如环境湿度大、氮肥施用过多、通风透气不良则更易蔓延。白粉病在花卉中较常见,以气温较高的     

普洱茶发酵清洁化车间的设计及环境湿度的控制

 传统的普洱茶发酵是采用人工在车间内自然渥堆发酵,这种发酵方式不能保证普洱茶发酵过程中湿度的均匀性,对普洱茶生产厂房和发酵车间进行设计和研究,将微生物技术、机械加工技术和电气控制技术融为一体,使普洱茶的生产规范化,并具有科学性。普洱茶发酵清洁化车间结合了传统发酵的技术,采用现代化的检测控制技术及设备,由湿度传感器、PLC主控设备、计算机处理系统、加湿设备和监控系统等构成。本文通过构建普洱茶发酵清洁化车间,对车间内的环境湿度进行控制,使普洱茶在发酵过程中的环境稳定,并在这种环境下进行了生产试验,得到试验的相关数据并进行处理,从试验数据中找出普洱茶发酵湿度对普洱茶品质形成影响的一些规律,为普洱茶发酵的规模化生产提供相应的科学参数。     

草地螟选择大画眉草而非藜产卵的证据及原因

为了阐明草地螟对产卵寄主的选择性,为改善其测报、防治技术提供科学依据,笔者于2008年8月在河北康保对草地螟的产卵寄主植物进行了系统的调查。主要结果为:在所调查的9科23种植物中,查到有草地螟产卵的有7科13种。成虫对禾本科的大画眉草[Eragrostis cilianensis(All.)Link ex Vignolo-Lutati]具有显著的偏好。大画眉草的单株着卵量、有卵株率、卵密度及相对着卵量均显著高于藜(Chenopodium album Linnaeus)等其他产卵寄主的对应值,并比藜上的对应值多10倍到100倍以上。对此次草地螟成虫主要选择大画眉草产卵的可能原因进行了探讨分析。     

环境湿度对火麻单纤维力学性能的影响

火麻韧皮纤维束强度高,韧性好,其力学性能主要由单纤维决定。研究采用离析法从火麻韧皮纤维束中提取出单纤维,利用纤维微拉伸测试技术对其开展了力学测试,同时考虑了环境湿度对单纤维力学参数的影响。结果表明,环境湿度从20%增加到70%的过程中,火麻单纤维的弹性模量和抗拉强度随环境湿度的增加逐渐降低,断裂应变则随着环境湿度的增加而逐渐增加,其中,弹性模量从29.88 GPa下降至8.30 GPa,抗拉强度从427.32 MPa降至150.58 MPa,而断裂应变则从2.26%增加至2.93%。     

如何防止鸭舍潮湿

鸭舍易潮湿是养鸭业的难题，同时电是鸭发病的主要诱因之一。潮湿的环境不仅为蚊、蝇、细菌、病毒等致病微生物繁衍孳生创造条件，也为鸭皮肤病、腿病、各种细菌感染增加了机会。因此，如何有效控制鸭舍的环境湿度是每个养鸭场、养鸭户考虑的实际问题。现结合工作实践体会，认为以下方法较为切实可行。     

高压喷雾加湿系统在蚕种催青上的应用

蚕种催青、蚕种保护等环节对环境湿度要求较高,通常情况下当空气湿度低于目的湿度时,就需要向空气补充水分,即加湿.     

雏鹅网床电热育雏技术要点及注意事项

雏鹅生产是养鹅过程中的重要环节,育雏效果的好坏决定着育成期中鹅的体况、数量及鹅群均匀度,对于养鹅业快速发展具有重要的意义。网床电热育雏具有温度控制稳定,受热均匀,减小环境湿度,提高空气质量等优点,有效提高育雏成活率,降低劳动强度,减少能源浪费和饲料污染,增加经济、社会和生态效益。论文旨在介绍网床电热装置的建设,应用中的注意事项及优点,以期为广大养鹅户的育雏工作提供参考。     

环境湿度对白桦木材尺寸稳定性的影响

对白桦木材在不同环境湿度下的尺寸稳定性进行了试验研究,试验表明:白桦小试件的含水率随环境湿度变化的时间较短,在正常的湿环境中1~2d内就与周围的环境达到平衡;较大尺寸的家具拼板材在干燥的环境中解吸速度较慢,需要较长的时间,同样在潮湿的环境中吸湿较慢,要达到与周围的环境相平衡同样需要比小试件更长的吸湿时间。     

专家热线

广东读者韦春华问：怎样运用生态养蛇技术？ 1．温度：蛇体温随着自然界的气温升降而变化，其活动也随着气温的升降而增减。在28～35℃时活动量最大，食量大。生长快；18℃以下食量减少，13℃以下不吃食物。因此，要控制好局部环境温度。2．空气相对湿度：湿度利于蛇类脱皮和生产。湿度大，蛇类易发病，湿度小，蛇类易掉膘。控制好局部环境湿度才能养好生态蛇。