遮荫对茶树新梢叶绿素及其生物合成前体的影响

研究了遮阳网遮荫处理对鸠坑、龙井43、水古新梢叶绿素生物合成前体物质和新梢叶绿素积累的影响。结果显示：遮荫降低光照强度,茶树新梢叶绿素含量显著增加;同时叶绿素生物合成的前体物质δ-氨基酮戊酸（aminolevulinic acid, ALA）、卟啉胆色素原（porphobilinogen, PBG）、尿卟啉原Ⅲ（Urogen Ⅲ）等含量降低,而原卟啉Ⅸ（protoporphyrin Ⅸ, ProtoⅨ）、镁原卟啉Ⅸ（magnesium protoporphyrin Ⅸ, Mg-ProtoⅨ）、原叶绿素酸酯（protochlorophyllide, Pchlide）含量升高。     

Precision phenotyping of imidazolinone-induced chlorosis in sunflower

Chlorosis level is a useful parameter to assess imidazolinone resistance in sunflower (Helianthus annuus L.). The aim of this study was to quantify chlorosis through two different methods in sunflower plantlets treated with imazapyr. The genotypes used in this study were two inbred lines reported to be different in their resistance to imidazolinones. Chlorosis was evaluated by spectrophotometrical quantification of photosynthetic leaf pigments and by a bioinformatics-based color analysis. A protocol for pigment extraction was presented which improved pigment stability. Chlorophyll amount decreased significantly when both genotypes were treated with 10 μM of imazapyr. Leaf color was characterized using Tomato Analyzer^® color test software. A significant positive correlation between color reduction and chlorophyll concentration was found. It suggests that leaf color measurement could be an accurate method to estimate chlorosis and infer chlorophyll levels in sunflower plants. These results highlight a strong relationship between imidazolinone-induced chlorosis and variations in leaf color and in chlorophyll concentration. Both methods are quantitative, rapid, simple, and reproducible. Thus, they could be useful tools for phenotyping and screening large number of plants when breeding for imidazolinone resistance in this species.     

DIFFERENTIAL TRANSLOCATION OF 59IRON IN IRON SUFFICIENT AND DEFICIENT SORGHUM PLANTS

Radioactively labeled iron (⁵⁹Fe) was used to study differential uptake in sorghum plants in the recovery stage of chlorosis. Radio-labeled ⁵⁹Fe was supplied through root feeding in nutrient solution experiment (48 hrs, pH 6.2) to non-chlorotic and chlorotic plants. Chlorotic plants were further treated with foliar spray [ferrous sulfate (FeSO₄), FeSO₄ + thiourea (TU), FeSO₄ + citric acid (CA), FeSO₄ + thioglycollic acid (TGA)] to study the uptake of radio-labeled ⁵⁹Fe through root feeding during recovery process of chlorosis. Under iron deficiency, the differential uptake of ⁵⁹Fe was markedly increased in leaves and stem of chlorotic control (-Fe) sorghum plants as compared to non-chlorotic control (+Fe) and foliar sprayed (FeSO₄, FeSO₄ + TU, FeSO₄ + CA, and FeSO₄ + TGA) plants. The lowest uptake of ⁵⁹Fe was observed in younger leaves (24.33 nmol, g^?1 fresh weight h^?1) and stem (1.98 nmol, g^?1 fresh weight h^?1) of non-chlorotic control followed by foliar sprayed plants in comparison to chlorotic control, respectively. Similarly less ⁵⁹Fe uptake was observed in the older leaves of FeSO₄ + CA sprayed (21.70 nmol, g^?1 fresh weight h^?1) plants in comparison to chlorotic control (35.60 nmol, g^?1 fresh weight h^?1). The highest differential ⁵⁹Fe uptake through nutrient medium was in the roots of plants, which were foliar sprayed with FeSO₄ along with TU. The role of iron alone and along with citric acid and thiol compounds is discussed in recovery of chlorosis.     

绿茶汤呈色物质研究进展

绿茶汤色的碧绿稳定是茶饮料品质好坏的重要指标。作者综述了有关对绿茶饮料的色泽有贡献的化合物的研究现状,主要包括黄酮醇及苷、儿茶素的氧化产物,花青素和叶绿素;并结合作者的研究结果,探讨了茶汤存放过程中,呈色物质的转化规律,旨在为茶饮料护色方案的选择提供理论支持和新思路。     

Pigment Composition of Nine Brown Algae from the Iberian Northwestern Coastline: Influence of the Extraction Solvent

Brown algae are ubiquitously distributed in the NW coastline of the Iberian Peninsula, where they stand as an underexploited resource. In this study, five solvents were applied to the extraction of pigments from nine brown algae, followed by their determination and quantification by HPLC-DAD. A total of 13 compounds were detected: Six were identified as chlorophylls, six were classified as xanthophylls, and one compound was reported as a carotene. Fucoxanthin was reported in all extracts, which is the most prominent pigment of these algae. Among them, L. saccharina and U. pinnatifida present the highest concentration of fucoxanthin (4.5–4.7 mg∙g⁻¹ dry weight). Ethanol and acetone were revealed as the most efficient solvents for the extraction of pigments, showing a maximal value of 11.9 mg of total pigments per gram of dry alga obtained from the ethanolic extracts of H. elongata, followed by the acetonic extracts of L. ochroleuca. Indeed, ethanol was also revealed as the most efficient solvent according to its high extraction yield along all species evaluated. Our results supply insights into the pigment composition of brown algae, opening new perspectives on their commercial exploitation by food, pharmaceutical, and cosmeceutical industries.     

光照强度对菠菜光合色素的影响

本丈以400、240、50μmol·m^-2·s^-1 3种不同光照强度处理菠菜,测定菠菜叶片中叶绿素a、叶绿素b、β-胡萝卜素和叶黄素含量的动态变化。结果表明：菠菜叶绿素a、叶绿素b的含量随着光照强度的增强而逐渐升高,且在高光强（4000μmol·m^-2·s^-1）下．植株叶片中2种色素含量随处理时间的延长呈逐渐升高的趋势,对照（2400μmol·m^-2·s^-1）植株含量在处理期间无明显变化．低光强（500μmol·m^-2．s^-1）下,2种色素含量呈降低的趋势,30d时各处理间差异显著;β-胡萝卜素含量随着光照强度的降低呈升高的趋势,30d时低光强处理植株含量显著高于对照和高光强处理植株;叶黄素含量：低光强〉高光强〉对照,20d和30d时．低光强处理植株含量显著高于高光强和对照植株。可以推论,高光强有利于菠菜叶绿素的合成,低光强有利于类胡萝卜素的形成。     

光照敏感型新梢白化茶新品种‘御金香’春梢化学成分研究

用HLPC法检测了光照敏感型新梢白化茶品种‘御金香’春梢生物碱、儿茶素类、氨基酸类和光合色素类化合物含量,并以温度敏感型新梢白化茶品种‘白叶1号’和常规茶树品种‘福鼎大白茶’为对照。结果显示,‘御金香’咖啡碱和可可碱含量显著高于‘福鼎大白茶’和‘白叶1号’;儿茶素类总含量显著低于‘福鼎大白茶’和‘白叶1号。光照敏感新梢白化茶‘御金香’和温度敏感型新梢白化茶‘白叶1号’的氨基酸含量显著高于‘福鼎大白茶’,但叶绿素a和叶绿素b、β-胡萝卜素、黄体素和新黄质等光合色素含量显著低于‘福鼎大白茶’。‘御金香’呈现黄色叶片的白化现象主要是因为叶绿素含量低,而并非类胡萝卜素含量高所致。     

菠菜叶绿素的提取优化及其酪蛋白分散体系的研究

叶绿素是一种天然的色素添加剂,但因其疏水性及加工与贮存条件下的不稳定性在食品工业中的应用受到了限制。因此,本研究在优化菠菜叶绿素提取工艺的基础上,利用酪蛋白酸钠的双亲特性,采用反式溶剂法将菠菜叶绿素包封于酪蛋白分散体系中,并评价叶绿素和叶绿素-酪蛋白分散体系的稳定性。结果表明,以无水乙醇为提取溶剂,提取温度50℃,超声波300 W,提取时间30 min,叶绿素提取量可达最大值1.89 mg/g;酪蛋白可减少叶绿素的光降解,提高叶绿素溶液颜色稳定性,含有等浓度叶绿素的乙醇溶液和酪蛋白溶液经过光照(9 000 lx)处理后的叶绿素保留率分别是56.07%和62.96%;同等处理条件下,叶绿素-酪蛋白酸钠溶液总色差(ΔE)小于叶绿素乙醇溶液总色差;叶绿素-酪蛋白分散体系在光照过程中zeta绝对值范围是30.6～38.2 mV。综上所述,酪蛋白酸钠包封叶绿素提高了叶绿素在水体系中的稳定性。该研究结果为拓宽叶绿素的应用提供了依据。