不同颜色果袋对‘云红梨2号’果皮色泽形成的影响

研究了不同颜色果袋对‘云红梨2号’果实着色的影响,比较了不同套袋处理下果皮外观着色、叶绿素、类黄酮、总酚、花色素苷含量以及花色素苷合成相关酶活性的差异.结果表明: 发育期的黑暗处理有利于解袋后梨果皮着色;不同套袋处理中,采前解袋自然光照射下梨果皮中花色素苷含量最高,着色最好,白色纸袋次之.不同套袋处理显著影响果皮中叶绿素、类黄酮、总酚和花色素苷含量,从而影响梨果皮的外观色泽.不同套袋处理的花色素苷合成酶活性差异显著;相关性分析表明,果皮中花色素苷含量与二氢黄酮醇-4-还原酶(DFR)和类黄酮3-O-葡萄糖基转移酶(UFGT)活性呈显著正相关,而与苯丙氨酸解氨酶(PAL)活性相关性不显著.     

子莲新品种‘武植子莲1号’和‘武植子莲2号’产量与营养品质分析

对子莲（Nelumbo nucifera Gaertn.）新品种‘武植子莲1号’和‘武植子莲2号’与其他12个主栽子莲品种的莲子产量和品质性状进行分析,并通过隶属函数分析法对他们的营养品质性状进行综合评价。结果显示：不同子莲品种的产量和营养品质性状差异显著,同一品种在不同发育时期莲子的可溶性糖和淀粉含量等营养指标差异较大;鲜莲子的可溶性糖含量显著高于成熟莲子,而蛋白质和淀粉含量显著低于成熟莲子。与12个主栽子莲品种相比,‘武植子莲1号’在产量上较为突出,成熟莲子的淀粉含量达52.15%,是生产天然淀粉的优良品种;‘武植子莲2号’鲜莲子的直链淀粉和支链淀粉含量低,可溶性糖含量达23.43%,适合鲜食。隶属函数分析结果表明,‘武植子莲1号’和‘武植子莲2号’的综合营养品质较好,具有很高的应用价值。     

杨品种‘普瑞’和‘107’对模拟酸雨胁迫的生理响应

通过测定杨(Populus×euramericana)抗硫新品种‘普瑞’和‘107’在3种梯度酸雨胁迫下的各项生理指标,研究酸雨胁迫对2个杨品种影响的差异。结果显示,在酸雨胁迫下,‘普瑞’叶片受伤害程度明显轻于‘107’,可以维持较稳定的光合作用,显示出较强的抗酸雨胁迫能力。酸雨胁迫下,‘107’光合作用强度显著下降,非气孔因素是其下降的主要原因。酸雨在一定程度上破坏了2个杨品种的水分平衡,尤其对‘107’的影响程度更为明显,但气孔关闭不是引起其光合作用强度下降的主要原因。研究结果表明杨品种‘普瑞’在酸雨环境下具有更强耐受性。     

Procyanidin B2 catabolism by human fecal microflora: Partial characterization of ‘dimeric’ intermediates

The catabolism by human fecal microflora of pure procyanidin B2 ((-)-epicatechin-4β → 8-(-)-epicatechin) has been investigated using a static in vitro culture model. For the first time, 24 catabolites were detected by LC-MS⁽ⁿ⁾ with M_r greater than 290 indicating that they could not have formed from just one of the epicatechin units in the procyanidin structure. Structures have been assigned on the basis of the fragmentation in the ion trap mass spectrometer and with regard to catabolic pathways known to occur in fecal microorganisms. Twenty of these ‘dimeric’ catabolites produced fragment ions characteristic of flavanols and/or proanthocyanidins. One catabolite was identified tentatively as either 6- or 8-hydroxy-procyanidin B2. Thirteen were characterized as having been microbially reduced in at least one of the epicatechin units. Five contained an apparently unmodified epicatechin unit but in at least one case this was shown to consist of the B-ring of the “upper” epicatechin unit and the A-ring of the “lower”. These ‘dimeric’ catabolites were detected up to 9 h after the start of the incubation and collectively accounted for ∼20% of the substrate.