Application of an orcinol-ferric chloride colorimetric assay in barley and wheat accessions for water-extractable and total arabinoxylan

Arabinoxylan is an important hemicellulose potentially affecting wheat baking qualities, barley malt quality, and may impart prebiotic benefits. Water-extractable (WEAX) and total arabinoxylan (TOAX) were characterized in 204 wheat and barley accessions, respectively, using an orcinol-ferric chloride assay. WEAX measurement accuracy was optimum when glucose concentration was greater than 12–13 times pentose concentration. The modified method removed enough excess glucose spectral absorbance to make the corrected and uncorrected lines different, but still significantly correlated (p = 0.009, R = 0.94). Mean WEAX (expressed as percentage WEAX of TOAX) for the wheat accessions was 15.90%, ranging from 8.82% to 24.87%, and for barley accessions WEAX the mean was 7.10%, and ranged from 2.98% to 13.86%. Conclusions are 1) the assay is useful for a breeding program because of its semi-high throughput design for the simultaneous analysis of 16 (WEAX) to 40 (TOAX) barley lines or 24 (WEAX) to 40 (TOAX) wheat lines, 2) the trichromatic measurement reduces the impact of glucose, and 3) the broad range of WEAX measured showed that barley and wheat accessions vary in their extractable and unextractable components.     

短时低温对柑橘大实蝇1~4级蛹恒温代价的弥补效应

柑橘大实蝇Bactrocera minax(Enderlein)为我国重要的柑橘类害虫。为了解短时低温对柑橘大实蝇1~4级蛹恒高温代价的弥补效应,以25℃恒高温为基础,研究了相对低温10、15、20℃短时(2、4、8h)变温处理柑橘大实蝇1~4级蛹后其成虫羽化情况。相对于恒温25℃,经15℃和20℃短时(2~8h)变温处理1级蛹后成虫羽化增长率为14%~47%,经10℃和15℃短时(2、4、8h)变温和20℃短时(4h)变温处理2~3级蛹后成虫羽化增长率为2%~45%,经10、15℃和20℃短时(2、4、8h)变温处理4级蛹后成虫羽化增长率为28%~46%,均表现为正增长,产生了恒温代价弥补正效应。4级蛹经10、15、20℃变温处理2h和8h,对其恒温代价弥补正效应均较2~3级蛹的大。总之,特定时长低温对特定蛹级产生恒温弥补正效应,不同蛹级间效应有差异。本研究结果为室内柑橘大实蝇保存,及春季快速回暖或田间倒春寒情况下柑橘大实蝇种群动态的预测预报提供依据。     

The effect of papermill wastewater irrigation and gypsum soil amendments on sodium accumulation by cottonwood and soil

Gypsum soil amendments affected the concentrations of sodium in the stems and leaves of Populus seedlings irrigated with pulpmill effluent. Concentrations of sodium in the sapling tissues increased with gypsum applications which gave total calcium application rates of 175 mg Cal⁻¹ wastewater (ww) and decreased as calcium application rates were increased to 625 mg Cal⁻¹ ww. Conversely, stem biomass production decreased as calcium application rates increased to 175 mg Cal⁻¹ ww and then increased as calcium application increased to 625 mg Cal^t1̄ ww. This resulted in no significant differences across treatment in either total sodium uptake or removal of sodium from the soil by the Populus seedlings. Total sodium uptake by Populus was about 0.002% of wastewater inputs. Infiltration rate increased with the increasing gypsum application. Gypsum application rate was not associated with differences in the concentration and distribution of sodium in the soil profile but increased application rates were associated with decreased soil pH.