影响大麦叶肉原生质体分离和培养的一些因子（简报）

从大麦幼苗分离叶肉原生质体，５ｄ苗龄的较４ｄ及６ｄ以上苗龄的得率高。提高Ｃａ＾２＋浓度有利于原生质体的分离，浓度为１０ｍｍｏｌ／Ｌ时的得率最高。在以添加０．５ｍｇ／Ｌ２，４－Ｄ、１．０ｍｇ／Ｌ ＮＡＡ及０．５ｍｇ／Ｌ ＺＴ的改良ＭＳ培养基和微弱的光照条件下，原生质体能持续分裂，并形成小细胞团。     

The effect of Tyrophagus putrescentiae on Fusarium poae transmission and fungal community in stored barley in a laboratory experiment

The effect of Tyrophagus putrescentiae on Fusarium poae transmission and fungal community composition was studied in nonsterile barley grain. The experiments included following treatments： control barley without mites; barley containing l0 or 50 mites without preincubation on E poae （Tpl0 and TpS0）; barley containing 10 or 50 mites after preincubation on E poae （FTp 10 and FTp50）. The number of mites, suc cessful transfer of E poae, and changes in the fungal communities were examined after 21 d of experiment. Increase of deoxynivalenol （DON） content in the barley was chosen as a criterion of successful Epoae transfer. The preincubation of T. putrescentiae on Epoae increased DON level approximately to 800 and 300μg/kg of grain for FTpl0 and FTpS0, respectively. T. putrescentiae population growth in FTpl0 was lower than in Tpl0, while no difference was found between FTp50 and Tp50. Fungal communities were compared by amplification, cloning and sequencing of ITS fragments, and operational taxonomic units （OTU） analysis. The OTU analysis did not support the transfer ofF. poae via mites. From the analyzed clones, only 13 cloned sequences clustered with E poae in an OTU defined at distance level 0.07. The related clones originated from FTpl0, Tpl 0, Tp50 and control treatments, but not from FTp50. However, the presence of E poae in FTp50 was confirmed by PCR amplification with specific primers. The observation may be explained by different effect of mite population density, that is, in the high density, （FTp50 treatment） the fungus was overgrazed, while the lower population density （FTp 10） supported E poae transfer.