Mibei Elias K, Ambuko Jane, Giovannoni James J, Onyango Arnold N, Owino Willis O
Department of Food Science and Technology Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya.
Department of Plant Science and Crop Protection University of Nairobi Nairobi Kenya.
Food Sci Nutr. 2016 Apr 18;5(1):113-122. doi: 10.1002/fsn3.370. eCollection 2017 Jan.
African eggplants ( and . ) are among the most economically important and valuable vegetable and fruit crops. They are a major source of biologically active nutritional substances and metabolites which are essential for plant growth, development, stress adaptation and defense. Among these metabolites are the carotenoids which act as accessory pigments for photosynthesis and precursor to plant hormones. Though African eggplants are known to be resistant to various abiotic stresses, the effect of these stresses on secondary metabolites has not been well defined. The objective of this study was to establish the effect of drought stress on carotenoid profiles of nineteen African eggplant accessions selected based on leaf and fruit morphological traits. Stress was achieved by limiting irrigation and maintaining the wilting state of the crops. Fresh leaves were sampled at different maturity stages; before stress, 2 weeks and 4 weeks after stress for carotenoid analysis. The fresh harvested leaf tissues were immediately frozen in liquid nitrogen and ground. Analysis was carried out using a Dionex HPLC machine coupled to Photo Array Detector and Chromeleon software package (Thermo Fisher Scientific Inc, Waltham, Massachusetts, USA). Major carotenoids viz;. Xanthophylls (neoxanthin, violaxanthin, zeaxanthin and lutein) and carotenes (-carotene and -carotene), phytofluene, lycopene, phytoene as well as chlorophylls (chlorophyll-b and Chlorophyll-a) were targeted. The carotenoids increased with maturity stage of the crop. Although the stressed crops reported significantly decreased amount of carotenes, chlorophylls, neoxanthin and violaxanthin, the concentration of zeaxanthin increased with stress whereas lutein had no significant change. Chlorophyll-a was significantly high in all the control accessions. Two accessions reported significantly higher contents of carotenoids as compared to the other accessions. The results of this study indicate that water stress has significant impact on the concentration of some carotenoids and photosynthetic pigments. This will definitely add value to the study of stress tolerance in crops.
非洲茄子（和. ）是经济上最重要且最有价值的蔬菜和水果作物之一。它们是生物活性营养物质和代谢产物的主要来源，这些物质对植物生长、发育、胁迫适应和防御至关重要。这些代谢产物中的类胡萝卜素作为光合作用的辅助色素和植物激素的前体。尽管已知非洲茄子对各种非生物胁迫具有抗性，但这些胁迫对次生代谢产物的影响尚未明确界定。本研究的目的是确定干旱胁迫对基于叶片和果实形态特征选择的19份非洲茄子种质类胡萝卜素谱的影响。通过限制灌溉并维持作物的萎蔫状态来实现胁迫。在不同成熟阶段采集新鲜叶片；胁迫前、胁迫后2周和4周进行类胡萝卜素分析。新鲜收获的叶片组织立即在液氮中冷冻并研磨。使用与光电阵列检测器和Chromeleon软件包联用的戴安高效液相色谱仪（美国马萨诸塞州沃尔瑟姆的赛默飞世尔科技公司）进行分析。主要类胡萝卜素即；叶黄素（新黄质、紫黄质、玉米黄质和叶黄素）和胡萝卜素（β-胡萝卜素和α-胡萝卜素）、八氢番茄红素、番茄红素、六氢番茄红素以及叶绿素（叶绿素b和叶绿素a）是目标分析物。类胡萝卜素随着作物成熟阶段而增加。尽管受胁迫作物的胡萝卜素、叶绿素、新黄质和紫黄质含量显著降低，但玉米黄质的浓度随胁迫增加，而叶黄素没有显著变化。所有对照种质中的叶绿素a含量都显著较高。与其他种质相比，有两份种质的类胡萝卜素含量显著更高。本研究结果表明，水分胁迫对某些类胡萝卜素和光合色素的浓度有显著影响。这肯定会为作物胁迫耐受性的研究增添价值。
