植物工厂不同LED光照模式对生菜幼苗生长及光合特性的影响

通过研究不同LED光照模式对植物工厂中生菜(Lactuca sativa L.)幼苗生长及光合特性的影响,筛选适于植物工厂内生菜育苗的LED光照模式。本试验使用白色LED(W)、红色LED(R)和蓝色LED(B)为光源,光源与光照天数相结合组成9种处理,分别为:W19、R19、B19、W12B7、W12R7、B12W7、B12R7、R12B7、R12W7,以W19为对照。研究结果表明:W19、B19、W12B7、W12R7、B12W7、B12R7处理下生菜幼苗的茎长显著短于其它处理。R19、W12R7和B12R7处理下生菜幼苗的地上部干鲜重、叶面积以及整株光合速率均显著高于对照;硝酸盐含量显著低于对照。W19、R12W7和B12W7;B19、W12B7和R12B7处理下生菜幼苗的叶绿素、花青素含量均高于R19、W12R7和B12R7。B19、W12B7和R12B7处理下生菜幼苗的单叶光合速率和气孔导度均显著高于其他处理。在供试的处理中,W12R7和B12R7处理下生菜幼苗的地上部干鲜重和叶面积较高、茎长短、硝酸盐含量低、整株光合速率高,表现出明显的生长优势,较其它处理更适用于植物工厂生菜育苗。     

根区温度对水培生菜生长和矿质元素含量的影响

在水培条件下,研究了5个根区温度对生菜(Lactuca sativa L.)生长和矿质元素含量的影响。结果表明:随着根区温度的升高,生菜单株产量呈先增加后减少的趋势,在25℃时达到最大值,且干物质含量最高;根区温度对生菜叶片净光合速率和矿质元素含量的影响与对产量的影响相似,即在25℃时达到最大值。35℃根区温度处理下,根叶生长和地上部矿质元素的积累受到严重阻碍,生菜叶片硝酸盐含量显著下降。在5个根区温度处理中,25℃对水培生菜的生长及矿质元素的吸收最为适宜。     

Detection of Japanese flounder-specific DNA from gut contents of potential predators in the field

ABSTRACT:   Predation by invertebrates may be one of the major factors influencing the mortality of released flounder juveniles in the field. We developed a polymerase chain reaction (PCR)-based technique for the detection of Japanese flounder material from the gut contents of potential predators in the field. The PCR primers used here are flounder specific and encompass a 153 bp region from the right domain of the mitochondrial control region. With these oligonucleotide primers, PCR reactions yielded specific amplification products from the gut contents of some putative predators, including Matuta lunaris , Portunus gladiator , Sepioteuthis lessoniana , Suggrundus meerdervoorti , Platycephalus sp. and Rhyncopelates oxyrhynchus . Many animals with gut contents of unidentified fish material showed indication of predation on the flounder after release of hatchery reared flounder juveniles. The technique developed in the present study is useful not only for the survey of predation on the flounder by known species, but also for the search for novel potential predatory species in the field.