Vascular function in berries of Vitis vinifera (L) cv. Shiraz

Anatomical studies on the movement of a xylem tracer dye were combined with functional studies on changes in grape berry volume during final stages of berry ripening to gauge xylem effectiveness. Movement of a xylem tracer dye into pre-veraison fruit was compared with movement into post-veraison fruit by feeding a solution of acid fuchsin to excised shoots with bunches still attached, and then sectioning fruit for photo-microscopy. Those comparisons confirmed published studies showing an apparent blockage to dye movement along major vessels within the brush tissue of post-veraison fruit. However, our functional approach yielded a different impression of vascular activity. A continuation of xylem transport in ripening fruit was inferred from comparisons of berry volume where pedicels were either girdled (phloem interrupted, but xylem intact) or excised (both phloem and xylem interrupted). Volume changes in manipulated berries were compared with immediately adjacent intact control berries within the same bunch. Control fruit lost volume subsequent to 78 days after flowering (DAF) while manipulated fruit lost volume from the first day of treatment at 67 DAF. By harvest time at 95 DAF, both control fruit and girdled fruit had fallen to 91% and excised fruit to 46% of maximum volumes recorded around 78 DAF. Berry volume loss in girdled fruit was further enhanced by deficit irrigation. We conclude that xylem flow into those Shiraz berries must have continued beyond veraison despite dye evidence of a vessel blockage within the brush region of analogous post-veraison fruit.     

螺旋藻多糖生物活性及应用研究

螺旋藻多糖是从螺旋藻中分离提取一种生物活性物质,具有很多生物学活性。该文仅就近年对螺旋藻多糖生物学活性研究进展作一综述报道。     

Bacillus subtilis B2产1-脱氧野尻霉素（DNJ）发酵条件优化

为探索制备含有1- 脱氧野尻霉素(1-deoxynojimycin,DNJ)的降血糖功能性食品的新方法,以产DNJ 的菌株Bacillus subtilis B2 为初始菌株,以价廉的农产品加工副产物豆渣为原料,通过对发酵条件的优化,获得富含功能因子DNJ 的发酵液。结果表明：接种量对α- 葡萄糖苷酶抑制活性影响不明显,当接种量大于104 个/mL 时,发酵液的α- 葡萄糖苷酶抑制活性均在20 以上。而豆渣浓度、发酵温度、培养基初始pH 值及发酵时间对发酵液α- 葡萄糖苷酶抑制活性影响较大,在豆渣质量浓度30mg/mL,初始pH 值6～8,发酵温度40℃的条件下发酵48h,发酵液表现出较高的α- 葡萄糖苷酶抑制活性。以Bacillus subtilis B2 发酵豆渣的发酵液为原料开发含DNJ 的降糖功能食品,可以大大提高豆渣的利用价值,为降糖功能食品的开发利用开辟新途径。