Floridean Starch and Floridoside Metabolic Pathways of Neoporphyra haitanensis and Their Regulatory Mechanism under Continuous Darkness

Floridean starch and floridoside are the main storage carbohydrates of red algae. However, their complete metabolic pathways and the origin, function, and regulatory mechanism of their pathway genes have not been fully elucidated. In this study, we identified their metabolic pathway genes and analyzed the changes in related gene expression and metabolite content in Neoporphyra haitanensis under continuous dark conditions. Our results showed that genes from different sources, including eukaryotic hosts, cyanobacteria, and bacteria, were combined to construct floridean starch and floridoside metabolic pathways in N. haitanensis. Moreover, compared with those in the control, under continuous dark conditions, floridean starch biosynthesis genes and some degradation genes were significantly upregulated with no significant change in floridean starch content, whereas floridoside degradation genes were significantly upregulated with a significant decrease in floridoside content. This implies that floridean starch content is maintained but floridoside is consumed in N. haitanensis under dark conditions. This study elucidates the “floridean starch–floridoside” metabolic network and its gene origins in N. haitanensis for the first time.     

黑暗对矮牵牛幼苗叶片抗氧化生理指标的影响

以矮牵牛梦幻系列红色（Petunia hybrida ‘Dreams Red’）为试验材料,从幼苗抗氧化酶、可溶性蛋白质、丙二醛（MDA）及过氧化氢（H2O2）入手,探讨了黑暗对幼苗叶片衰老的影响及其在恢复过程中物质含量的变化。结果表明：黑暗处理1、4、15d后。可溶性蛋白含量分别降低13．3％、18．4％、22．9％、MDA、H2O2含量持续升高,MDA含量分别增加28．4％、78．4％及196．4％,H2O2含量分别上升了18．2％、31．3％及33．3％。过氧化物酶（POD）、超氧化物歧化酶（SOD）活性先升后降。黑暗处理后恢复过程中,各值均基本恢复到对照水平,且处理4d的植株叶片恢复较快,处理15d植株叶片膜系统受到一定损伤,但仍可缓慢恢复。     

基于计算机视觉的鱼体色明暗程度量化方法

当前．鱼类行为学在养殖生产中的应用还不普遍，但已经引起人们的重视。借助于现代技术手段监涸鱼的行为，研究不同应激条件下鱼的行为特点以及鱼的行为与水产养殖环境的关系。从而实现基于鱼行为变化的应激自动报警。是很有意义的。为此。利用计算机视觉技术近似量化水中鱼体色的明暗程度。将图像转换到HSV空间得到鱼体的明度值，与经校准后的无色玻璃覆盖的灰级各阶的明度值进行比较和线性擂值。近似用明度阶值表示鱼体色的亮暗程度。     

船舶压载舱黑暗条件对青岛大扁藻种群的生态影响

为阐明船舶压载舱的黑暗密闭环境对绿藻生长的影响,以青岛大扁藻为模式生物,设置不同的初始密度(5 cells/m L、50 cells/m L、5×10~2cells/m L、5×10~3cells/m L和5×104~cells/m L),研究青岛大扁藻在黑暗条件下的相对生长抑制率及在不同生长期和初始密度处理下的种群响应。并对黑暗处理后的青岛大扁藻进行光照恢复研究,探索在不同的起始密度下,未经黑暗与经黑暗处理后的扁藻种群密度变化的差异。结果表明,经过黑暗处理的低密度(3 cells/m L)的青岛大扁藻在光恢复两周后仍然可以达到较高的种群密度水平(1×10~3);经黑暗处理的青岛大扁藻在光恢复初始密度为3及3×10~4cells/m L时的种群恢复能力较未经黑暗处理的弱,且存在显著差异(P0.05)。     

Effect of initial darkness duration on the pathogenicity of Calonectria pseudonaviculata on boxwood

Light is an important environmental stimulus that regulates many physiological activities within plants and pathogenic fungi. Boxwood blight (causal agent: Calonectria pseudonaviculata) is a newly emergent disease in the United States and a significant threat to the boxwood industry. A disease‐forecasting model has been developed to aid boxwood growers in their management decisions, but light is not included as a variable within the programme. Growth chamber experiments were conducted to evaluate the effect of an initial dark period on disease severity, mycelial growth and conidial germination of C. pseudonaviculata. Treatments varied by darkness duration (0, 6, 12 or 24 h dark), and were followed by a 14 h day length at a 25/21 °C day/night temperature. Neither boxwood blight severity nor fungal colony development was enhanced by an initial dark period. However, darkness duration was associated with a significant increase in conidial germination in vitro. This study suggests the predictive performance of the current boxwood blight disease‐forecasting model would not be improved by inclusion of photoperiod.     

黑暗培养对苹果组培快繁及叶片再生的影响

为明确暗培养在苹果组培中的作用,研究了适当黑暗培养对苹果组培快繁及叶片再生的影响。新红星苹果茎尖外植体接种和生根阶段,1周暗培养有利于茎尖分化和不定根诱导。M26继代苗接种10d后进行10～15d的黑暗培养,可显著增加有效苗数量。乔纳金、王林苹果叶片再生经3周左右暗培养,可将再生率提高3倍多,再生芽数增加4～6倍。生理代谢分析表明,除淀粉含量外,暗培养试管苗的可溶性糖、氨基酸、蛋白质的含量均比光培养苗高。     

Effects of darkness on stem elongation in tulip

Effects of darkness during the growing-period on the internode elongation of tulips were investigated. The last internode was the longest one when grown under natural light conditions, while continuous darkness caused the first internode to elongate the most. Application of a 5-day dark treatment to growing tulips during the phase of rapid stem extension resulted in significant increase in the length of the first internode. It was effective in obtaining taller tulips owing to increased elongation of the first internode, and may be effectively applied to tulip cut-flower production.     

光照强度对樱桃谷肉鸭c-fos、生物钟基因表达及褪黑激素的影响

【目的】研究持续黑暗下给予樱桃谷肉鸭不同强度的瞬时光照,对下丘脑、间脑、垂体和中脑中c-fos基因及相关生物钟基因的表达及血浆和肝脏中褪黑激素含量的影响。【方法】选用144只健康且体重接近的1日龄樱桃谷肉鸭饲养至21日龄,22日龄时随机分为2组,每组6个重复,持续黑暗7 d,期间自由采食和饮水,分别采用10 Lx和80 Lx的LED白光刺激1.5 h,暗适应1.5 h后立即从每个重复选取1只接近平均体重的肉鸭,检测下丘脑、间脑、垂体和中脑c-fos和生物钟基因的表达量,检测血浆和肝脏褪黑激素含量。【结果】10 Lx组的下丘脑和中脑c-fos表达量显著高于80 Lx光照组(P<0.05),间脑中c-fos的表达量显著低于80 Lx光照组(P<0.05),两组垂体组织中c-fos表达无显著影响(P>0.05)。与80 Lx组相比,10 Lx组下丘脑生物钟基因Bmal1、Bmal2、Clock和Per2表达量均显著提高(P<0.05),Cry1表达量也有提高的趋势。10 Lx组间脑Bmal1的表达量显著提高(P<0.05),Bmal2、Clock、Per2和Cr...     

光暗处理对水稻叶片光合关键酶的效应

稻苗置暗中24h后,Rubisco含量及Rubisco与可溶性蛋白的比值随光强的增加而提高;经2h光照后再置黑暗中,Rubisco含量在最初20min下降迅速,说明苗期Rubisco蛋白在光暗交替下周转较快.Rubisco的初始活力在光照下迅速增加,其上升倍数大大高于量的增加,光强越大达到最大活力所需的时间越短.照光后把稻苗置暗中,Rubisco初始羧化活力很快下降,说明Rubisco的光下活化及暗中失活迅速.Rubisco活化酶的含量随光照增加而逐渐上升,光照处理后再置暗中Rubisco活化酶含量不断下降,但速率不如Rubisco.Rubisco活化酶的活化只依赖低光强,光照处理后再置黑暗中,Rubisco活化酶活力迅速下降.     

黑暗条件下不同贮藏方式和温度对辣椒穴盘苗质量的影响

以中椒22号辣椒为试材,在黑暗条件下研究不同贮藏方式及25、15、7℃温度对辣椒秧苗主要形态及生理指标的影响。结果表明:在贮藏过程中,辣椒秧苗的干重/鲜重、根冠比、根系活力、叶绿素含量明显下降,且7℃处理的下降幅度小于15℃和25℃处理;穴盘秧苗贮藏的横放效果好于竖放。贮藏结束后(9 d),15℃和25℃处理秧苗顶端会出现褐化现象。当秧苗定植到大田后,7℃处理的秧苗整体较其它处理生长速度快。表明7℃处理更适宜辣椒穴盘秧苗的贮藏。