Close planting of dwarf varieties is currently the main cultivation direction for pear trees,and the screening of excellent dwarf varieties is an important goal for breeders.In this study,the dwarfing pear variety‘6...Close planting of dwarf varieties is currently the main cultivation direction for pear trees,and the screening of excellent dwarf varieties is an important goal for breeders.In this study,the dwarfing pear variety‘601D’and its vigorous mutant‘601T’were used to show their biological characteristics and further explore the dwarfing mechanism in‘601D’.The biological characteristics showed that‘601D’had a shorter internode length,a shorter and more compact tree body,thicker and broader leaves,lower stomata density,larger stomata size(dimension),and higher photosynthetic capacity.The biological characteristics of‘601T’showed notable contrasts.The results of endogenous hormone tests indicated that the contents of abscisic acid(ABA),ABA-glucosyl ester,and GA_(4) were higher in‘601D’,but the trans-zeatin content was lower.By transcriptomic analysis,significant differences were found in the biosynthetic and metabolic pathways of ABA.Related transcription factors such as bHLH,WRKY,and homeobox also participated in the regulation of plant dwarfing.We therefore examined three hormones with obvious differences with‘601T’,and found that only ABA could induce‘601T’to return to a dwarfing plant phenotype.Therefore,we conclude that the dwarfing of‘601D’is caused by an excessive accumulation of ABA.This study provides a new theoretical basis for breeding dwarf varieties.展开更多
文摘采用小鼠生物检测法和液相色谱-荧光检测法,分别对采自钦州湾的7种典型经济贝类中麻痹性贝类毒素(paralytic shellfish toxins,PSTs)组成成分与含量进行分析,同时参考我国渔政渔港监督管理局制订的贝类安全食用标准(400 MU/100 g或80μg/100 g STX_(eq))评价其食用安全性。结果如下,小鼠生物法分析表明小鼠在观察15 min内均不死亡,说明7种贝类中PSTs含量均小于400 MU/100 g或者不含有毒素;进一步对贝类样品进行液相色谱-荧光检测分析,表明7种贝类中可检测到麻痹性贝类毒素,毒素组成成分以高毒性的氨基甲酸酯类毒素为主如膝沟藻毒素4(gonyautoxin,GTX4)、膝沟藻毒素1(gonyautoxin,GTX1)、新石房哈毒素(neosaxitoxin,NEO)和石房蛤毒素(saxitxin,STX),其中异毛蚶中有最大毒素含量/毒性值,分别为0.27 nmol/g或13.1μg/100 g STX_(eq),低于安全标准80μg/100 g STX_(eq)。研究中有6种贝类可检测到毒素成分,检出率为86%。这说明,在钦州湾所采集的7种贝类中,尽管毒素含量低于食用安全标准规定的阈值,但多种贝类中仍可检测到麻痹性贝类毒素成分,因此其存在的安全性问题不容忽视,应加强该地区经济型贝类中麻痹性贝类毒素的监测,以防中毒事件的发生。
基金funded by the National Key Research and Development Program of China(2018YFD1000100)the Agricultural Improved Variety Project Program of Shandong Province,China(2019LZGC008)the National Key Research and Development Program of China(2019YFD1001404-3)。
文摘Close planting of dwarf varieties is currently the main cultivation direction for pear trees,and the screening of excellent dwarf varieties is an important goal for breeders.In this study,the dwarfing pear variety‘601D’and its vigorous mutant‘601T’were used to show their biological characteristics and further explore the dwarfing mechanism in‘601D’.The biological characteristics showed that‘601D’had a shorter internode length,a shorter and more compact tree body,thicker and broader leaves,lower stomata density,larger stomata size(dimension),and higher photosynthetic capacity.The biological characteristics of‘601T’showed notable contrasts.The results of endogenous hormone tests indicated that the contents of abscisic acid(ABA),ABA-glucosyl ester,and GA_(4) were higher in‘601D’,but the trans-zeatin content was lower.By transcriptomic analysis,significant differences were found in the biosynthetic and metabolic pathways of ABA.Related transcription factors such as bHLH,WRKY,and homeobox also participated in the regulation of plant dwarfing.We therefore examined three hormones with obvious differences with‘601T’,and found that only ABA could induce‘601T’to return to a dwarfing plant phenotype.Therefore,we conclude that the dwarfing of‘601D’is caused by an excessive accumulation of ABA.This study provides a new theoretical basis for breeding dwarf varieties.
