宫内伊予柑果实发育期间色泽和色素的变化

 以宫内伊予柑为试材, 对果实发育期间色泽、色素种类及含量, 尤其是类胡萝卜素组分进行了研究。结果表明, 幼果中高含量的叶绿素使果实呈现青绿色, 采前8周起类胡萝卜素开始积累, 采前4周起随叶绿素含量下降黄色得以显现。果实类胡萝卜素主要存在于果皮中, 成熟果实果皮类胡萝卜素含量达囊瓣的16.62倍, 总量占整果的83.62%。用高效液相色谱—二极管阵列检测(HPLC - PDAD) 技术,对采前12周至采收期的果皮类胡萝卜素组成进行了分析, 共分离出类胡萝卜素组分23种, 其中7种得到鉴定。在采收期果皮中, 已鉴定的类胡萝卜素中以β - 隐黄质和玉米黄素较丰富, 占总类胡萝卜素的8.00%和6.78%; β - 胡萝卜素不足总类胡萝卜素的1% , 没有检测出α - 胡萝卜素和番茄红素。果实成熟过程中β - 隐黄质及玉米黄素含量上升, 并伴随α - 胡萝卜素、叶黄质和β - 胡萝卜素含量下降, 暗示类胡萝卜素的β主链合成能力和β环羟化活性急剧增强, 与此同时, 阿朴类胡萝卜素的出现则表明类胡萝卜素的裂解能力随果实成熟而上升。     

Presence of diverse ratios of lycopene/β-carotene in five pink or red-fleshed citrus cultivars

Pink or red-fleshed fruit mutations are commonly found in grapefruit, sweet orange, and occasionally in lemon, which combine novel appearance with fine eating quality. In order to identify the major coloured pigments, high performance liquid chromatography (HPLC) with ultraviolet detection was applied for the separation and characterization of carotenoids from five pink or red-fleshed citrus cultivars. As a result, both lycopene and β-carotene with similar HPLC profiles were detected in the five citrus cultivars, ‘Fengdu’ red-fleshed pomelo (Citrus grandis (L.) Osbeck), ‘Guanxi’ sweet pomelo red mutant, ‘Hirado Buntan’ pomelo, ‘Cara Cara Navel’ orange (C. sinensis (L.) Osbeck) and ‘Star Ruby’ grapefruit (C. paradisi Macf.). ‘Star Ruby’ contained the highest lycopene and β-carotene content in its flesh. However, although the significant correlation between the concentrations of lycopene and β-carotene was detected with a coefficient of 0.9692 (P < 0.01), ratios of lycopene/β-carotene were different among the cultivars. Post-harvest biosynthesis verified that the flesh itself synthesized carotenoids rather than acquiring them via transport from other tissues. In addition, a product feedback regulation mechanism might be involved in the process of carotenoid biosynthesis.     

红肉脐橙果肉中主要色素的定性及色素含量的变化

 运用薄层层析法及二极管阵列检测器与高效液相色谱联用的方法, 确定红肉脐橙果肉中含有番茄红素和β- 胡萝卜素两种主要色素, 它们在液相色谱图中占总峰面积(计溶剂峰) 的73. 57 %～77. 78 % , 番茄红素占55. 36 %～58. 49 % , β- 胡萝卜素占18. 21 %～19. 93 %。利用反相高效液相色谱仪以及番茄红素和β- 胡萝卜素标样制作标准曲线, 测定果实发育及室温贮存过程中色素的变化动态, 结果表明, 该脐橙果肉中的番茄红素在成熟期含量最高, 达109. 67μg·g^-1DM, β- 胡萝卜素此时也达到最高值(15. 52μg·g^-1DM) ; 番茄红素的含量在采收后基本呈下降趋势(但采后30 d 有显著升高) , 说明果肉中存在类胡萝卜素采后合成的现象; 贮存4 个月后, 番茄红素含量急剧降低至最高时的1/ 10。     

Expression of lycopene cyclase genes and their regulation on downstream carotenoids during fruit maturation of Guoqing No. 1 Satsuma mandarin and Cara Cara navel orange

Lycopene β-cyclase (LCYb) and lycopene ?-cyclase (LCYe) are believed to be crucial genes to lycopene cyclization and downstream carotenoid accumulation. To illuminate the gene expression profiles and their regulation on downstream carotenoids, expression profiles of these two genes and contents of several corresponding carotenoids were determined by real-time PCR and HPLC, respectively, in relative shorter intervals during breaker and maturation stage of Guoqing No. 1 satsuma mandarin (Citrus unshiu Marcow) and Cara Cara navel orange (Citrus sinensis Osbeck). Data showed that the expression profiles of these two cyclase genes and their relative expression levels between the peels and the pulps at the same stage all varied with cultivars. But in general, accumulation of lutein and β-carotene experienced a similar tendency in both cultivars and were up-regulated by expression of LCYb and LCYe in spite of poor correlation in the pulps. Meanwhile, lycopene abundance was negatively correlated with the expression of LCYe as expected, but hardly correlated with LCYb in the pulps of Cara Cara navel orange, indicating that LCYe might exert a more prominent influence on lycopene cyclization and downstream carotenoids formation. Results of carotenoids accumulation suggest that the biosynthetic process of carotenoids would shift from upstream β, ?- or β, β-carotenoids such as lutein and β-carotene to downstream β, β-carotenoids during fruit development.     

Separierung der spektralen Absorption einzelner Fruchtpigmente am Beispiel von Mango in der Frischhaltung

Breakdown and synthesis rates of green and yellow fruit pigments are well correlated with ripeness of tropical fruits and can be analysed precisely and cost-efficiently by spectrophotometry. In the present study postharvest observations of mango fruits (Mangifera indica L. ‘Kent’) and their varying maturity and quality related contents of chlorophylls, carotenoids and xanthophylls have been used to evaluate a new method for analysing spectral data by an iterative multiple regression algorithm (iMLR). The main objective was to establish this method as a laboratory application analysing fruit extracts in organic solvents and, furthermore, for non-destructive quality tests on fruit and vegetables. It is shown that varying contents of chlorophyll a and b as well as beta-carotene and violaxanthin could be calculated in a nonpolar solution of mango pigments using iMLR. As a mixture of mango pigments were determined using sets of linear equations, the error was higher compared to results of iMLR. The content of violaxanthin in overripe fruit exocarp was computed with 18.04 µg/g DW and thus significant higher than the content in unripe fruit exocarp (8.63 µg/g DW). The content of ß-carotene did not change during the time of storage. For analysing non-destructively recorded fruit spectra iMLR is applicable within limits. In diffusive tissue, corrections regarding the varying optical sample properties are needed. The measuring uncertainty was low for chorophyll, but high for single carotenoids.     

Expression of carotenogenic genes during the development and ripening of watermelon fruit

Five watermelon varieties with different flesh colors: “ZAOHUA” (red); “96B41” (pink); “307CHAOFENG” (yellow); “UNKNOWN” (orange); and “SANBAI” (white) were used to investigate the relationship between carotenoid profiles and expression of carotenoid-related genes during fruit development and ripening. In mature fruit, “ZAOHUA” and “96B41” accumulated high level of lycopene, “SANBAI” contained trace amounts of carotenoids. Through HPLC and dot blot hybridization, carotenoid content was analyzed and compared to the expression of carotenoid-related genes including Psy, Pds, Zds, CrtIso, Lcyb, Chyb, Nced1, Nced2, Nced3 during fruit development. All genes examined were expressed in all five watermelon varieties. In red and pink color varieties, the decrease of gene expression for Lcyb and Chyb at stage C (30 d after pollination) may be consistent with the high accumulation of lycopene and β-carotene. In the yellow variety, expression of the detected genes increased markedly with the onset of maturation, but little carotenoid accumulation was detected, which may be due to high level of carotenoid cleavage dioxygenases. Expression of all detected genes decreased rapidly in the white color variety upon fruit ripening, which may be attributed to a reduction in metabolic flux in the carotenoid pathway. These results imply the complex regulation of the carotenoid biosynthetic pathway in watermelon.     

Preferential accumulation of orange-colored carotenoids in Ponkan (Citrus reticulata) fruit peel following postharvest application of ethylene or ethephon

To avoid winter frost, Ponkan (Citrus reticulata Blanco cv. Ponkan) fruit in Zhejiang Province, China, is frequently harvested early, while chlorophylls are still present in the peel. Postharvest degreening of Ponkan fruit, through either ethylene fumigation or ethephon dipping, was carried out to study the effects of both treatments on color development and carotenoid accumulation. An earlier and deeper orange color development after treatments was indicated by a decline in hue angle (H°) and an increase in the citrus color index (CCI). Total carotenoid content increased, while chlorophyll content decreased during storage at 10 °C, and these changes were accelerated by both treatments. The treatments stimulated preferential accumulation of carotenoids with orange color (β-carotene and β-cryptoxanthin) while reducing the abundance of carotenoids with yellow color (lutein, violaxanthin and 9-cis-violaxanthin). Gene expression of β-carotene hydroxylase (BCH) was inhibited by both treatments, which could be related to the changes in composition of these differently colored carotenoids.     

红肉脐橙番茄红素β-环化酶基因的克隆及在大肠杆菌中的功能表达

以'红肉脐橙'（Citrus sinensis Osbeck 'Cara Cara'）果实中分离的mRNA为模板,经RT-PCR扩增到约1.6 kb的番茄红素 β-环化酶（lycopene β-cyclase,Lcyb）cDNA片段。序列分析表明,该cDNA长1654 bp,包含两个转录本Lcyb1和Lcyb2,最大开放读码框均为1512 bp,可编码504个氨基酸。通过PCR方法获得红肉脐橙Lcyb1和Lcyb2 cDNA编码区全长,构建了Lcyb1和Lcyb2的原核表达载体pET-CitLcyb1和pET-CitLcyb2,并通过颜色互补试验证实表达的融合蛋白6×His-Lcyb1和6×His-Lcyb2均可将番茄红素转化为β-胡萝卜素。     

早熟优质蜜柚新品种——红肉蜜柚的选育

红肉蜜柚系琯溪蜜柚优变芽系选育而成。果大、无子、空心、皮薄;风味酸甜适口,肉质细嫩化渣,总糖、总酸、维生素C含量分别为8.76%、0.74%、0.38mg/g;汁胞呈红色,色素成分主要为β-胡萝卜素与番茄红素,含量分别达(72.15±17.13)、(41.10±2.24)μg/g,叶黄素微量;成熟期9月下旬至10月初;盛产树666.7m2产量2000kg以上。     

超量表达欧李ChPSY基因促进转基因番茄类胡萝卜素合成的研究

将从欧李果实中分离的ChPSY cDNA经过序列分析、酶切之后,连接到植物表达载体PMV,构建了植物重组载体pBI-ChPSY,并通过根瘤农杆菌EHA105介导转化番茄,获得了12株抗性植株。PCR检测和Southern杂交结果显示,12株抗性植株均为阳性,说明外源基因ChPSY整合到转化植株的基因组中。RT-PCR分析表明,ChPSY基因在转化植株果实中得到表达。HPLC分析表明,转ChPSY基因番茄果实中总类胡萝卜素含量增加了1.62 ~ 3.04倍,八氢番茄红素、番茄红素、β–胡萝卜素和α–胡萝卜素含量分别增加了4.87、2.10、2.59和3.25倍。转化植株中内源类胡萝卜素合成基因的表达也受到广泛的影响。ChPSY基因超量表达有效促进了番茄果实中类胡萝卜素的合成和积累。     

欧李番茄红素β–环化酶基因ChLCYb的分离与功能鉴定

利用RACE技术和RT-PCR相结合,从欧李[Cerasus humilis(Bge)Sok]果实中克隆获得长度为1798 bp的番茄红素β–环化酶(lycopeneβ-cyclase)基因ChLCYb的cDNA全长序列,开放读码框为1515 bp,编码503个氨基酸。序列分析发现,ChLCYb具有植物LCYb保守区(Plant LCYb conserved region)、FAD/NAD(P)结合区(Dinucleotide-binding signature)、"Cyclase motif 1"、"Cyclase motif 2"和"lycopeneβ-cyclase motif"等典型结构特征,在N–端存在1~84个氨基酸残基组成的转运肽信号序列,在85~106、209~227、373~391和460~480氨基酸区域包含4个跨膜结构域。荧光定量PCR结果表明,ChLCYb在叶中表达量最高,其次是幼果,在根中最低;在欧李果实发育过程中,果皮中ChLCYb表达量高于果肉,果皮中ChLCYb表达量先升高,在花后90 d左右表达量最高,然后呈缓慢下降趋势,而果肉中ChLCYb表达量相对平稳。ChLCYb表达模式与果皮和果肉中β–胡萝卜素含量的积累呈显著正相关(r=0.824和r=0.712,P0.05)。利用大肠杆菌工程菌体系诱导表达了ChLCYb蛋白,并证实其可催化工程菌株中番茄红素向β–胡萝卜素转化,其转化效率达71.22%。在番茄中超量表达ChLCYb促进果实中番茄红素向β–胡萝卜素的转化和积累,转基因株系L-11号果实中的β–胡萝卜素含量高达692.18μg·g~(-1) DW,是非转基因对照的4.42倍。     

套袋对‘三红蜜柚’果实着色的影响

【目的】‘三红蜜柚’[Citrus maxima(Brum.)Merr.‘Sanhongmiyou’]的海绵层和果肉红色,外果皮橙黄色,经套袋后也呈现紫红色,但套袋对外果皮呈色的作用机制尚不清楚。因此,本研究通过分析不同套袋对外果皮色素积累的影响,筛选出最适套袋方案,指导生产,也为今后进一步研究果面色泽形成机理提供研究基础。【方法】以’三红蜜柚’果实为试材,分别选用3种不同的果袋对果实进行套袋,以不套袋作为对照,测定果实在发育期间的外果皮色泽参数、叶绿素和类胡萝卜素含量,使用超高效液相色谱法测定外果皮番茄红素、β-胡萝卜素和玉米黄素的含量。【结果】3种套袋处理的果皮亮度值L*、红绿色度值a*、黄蓝色度值b*和色泽饱和度在果实发育过程中均呈上升趋势,显著高于对照组;在3种套袋处理间,L*值无显著差异,处理A和处理B的果实比处理C的果实更早退绿,更早着色。相比较于对照组,套袋处理能够显著提高成熟果实果皮的番茄红素含量,不同处理间的果皮番茄红素含量差异显著,其中,处理A的果皮番茄红素含量最高,达44.54 mg·kg^-1。在果实发育过程中,套袋处理果实的果皮β-胡萝卜素、玉米黄素、叶绿素a、叶绿素b和类胡萝卜素的含量均呈下降趋势,显著低于对照组。【结论】套袋显著降低‘三红蜜柚’果实的果皮叶绿素含量,促使果皮提前退绿;双层和三层果袋显著提高成熟期果实的果皮番茄红素含量,增加果皮的红色成分,有效提高‘三红蜜柚’果实的果面着色效果。     

Interaction of Crop Load and Irrigation on Yield,Fruit Size,Color and Stem-end Splitting Ratio of Apple c.v. ‘Gala,Galaxy’

In this study, the interaction between crop load and irrigation level on yield, fruit size, skin color and stem-end splitting fruit ratio in the apple cultivar ‘Gala, Galaxy’ grafted on rootstock M9 were investigated. Six irrigation programs were applied during the whole growth season: deficit irrigation (rates of 0.25 kc, 0.50 kc, 0.75 kc), full irrigation (rate of 1.00 kc), excess irrigation (rate of 1.25 kc) and non-irrigation (rates of 0.00 kc of “Class A” pan evaporation coefficient). Four crop loads in each irrigation application were performed by hand thinning after the June drop as a- a low crop load (3 fruits cm^?2 TCA), b- a medium crop load (5 fruits cm^?2 TCA), c- a heavy crop load (7 fruits cm^?2 TCA), and d- an un-thinned crop load (>?7 fruits cm^?2 TCA). The total tree yield increased with crop load and irrigation levels. Fruit size was significantly increased by the low crop load. Irrigation increased the fruit size compared to non-irrigation treatment. Further 0.75 kc, 1.00 kc and 1.25 kc irrigation treatments significantly increased the fruit length. Irrigation reduced the fruit flesh firmness. While the low crop load increased the skin red color, it decreased the fruit skin brightness. The yellowness of skin decreased with increasing in the irrigation amount. Irrigation reduced the skin brightness and yellowness, but it increased red color. Crop load and irrigation significantly affected the stem-end splitting fruit ratio. While the splitting fruit ratio increased with a decrease in the crop load, it decreased with an increase in irrigation amount, relatively. Consequently, the low and medium crop load treatments would be beneficial to increase the ratio of marketable fruits without any significant losses in yield for ‘Gala’ apple, especially under 0.75 kc deficit irrigation treatment.     

两种不同肉色枇杷果实类胡萝卜素积累及合成#br# 相关基因的表达

 以‘早钟6 号’（黄肉）和‘白玉’（白肉）两类枇杷为材料,测定不同发育阶段果实果皮 和果肉中类胡萝卜素含量,并对15 个生物合成相关基因的表达进行了分析。随着果实发育成熟,β–胡 萝卜素含量在黄肉‘早钟6 号’果皮和果肉中增加,到成熟期达到最高值,分别为68.53 和11.92 μg ? g-1 FW; 在白肉的‘白玉’果皮中也呈增加趋势,到成熟期最高,为38.89 μg ? g-1 FW,但果肉中略有下降,从最 初的0.47 μg ? g-1 FW 降低至0.29 μg ? g-1 FW。两个品种果皮和果肉的β–隐黄质含量表现为持续增加,均 在成熟期达到最高值。叶黄质含量在‘早钟6 号’果皮中表现为下降,在果肉中则持续上升;在‘白玉’ 果皮中表现为先降后升,在果肉中变化不大,维持较低水平。‘早钟6 号’进入转色期后,与‘白玉’相 比,在果皮中的PSY 和CYCB 表达量较高,而在果肉中CYCB 和BCH 的表达量较高,提示枇杷不同发育 阶段类胡萝卜素的积累主要受PSY、CYCB、BCH 基因的共同调控。     

Effects of 22S, 23S-Homobrassinolide and Gibberellic Acid on Occurrence of Physiological Disorders and Fruit Quality of ‘Summit’ and ‘Regina’ Sweet Cherries

Plant growth regulators play a vital role in fruit growth and development. However, effects of compounds belonging to the group of brassinosteroids have not been fully investigated in sweet cherries. One relatively new and one commonly applied growth regulator, 22S, 23S-Homobrassinolide and GA₃, respectively, were tested on ‘Summit’ and ‘Regina’ sweet cherries to determine the effects on fruit quality and physiological disorders. The substances were applied with a handgun sprayer at full bloom and at the beginning of fruit development (shuck split) for a 2-year period. GA₃ was applied at the concentrations of 25, 50, 100 mgL^?1 and 22S, 23S-Homobrassinolide at 0.05, 0.1, 0.5 mgL^?1. A combined application of 100 mgL^?1 GA₃ + 0.1 mgL^?1 22S, 23S-Homobrassinolide was also applied. Effects of GA₃ and 22S, 23S-Homobrassinolide on fruit weight and size were evident for the concentrations applied and between the seasons for both of the cultivars. Combination of the both growth regulators and 100 mgL^?1 GA₃ alone produced longer fruits compared to the control trees in ‘Regina’. The 22S, 23S-Homobrassinolide applications increased the firmness of the flesh slightly, but not to a great degree, compared to the GA₃ applications alone. The brightness of the red color was better with GA₃ applications in ‘Summit’ and ‘Regina’. Brassinosteroid caused the fruits to have comparably dull red color. Total soluble solid contents of the cultivars were influenced by the substances and the year of the application. Stem resistance to separation from the fruit was under the influence of both treatments and seasons. In general, 22S, 23S-Homobrassinolide provided better stem resistance than the GA₃ applications. There were no effects of the substances on the development of physiological disorders.     

无籽西瓜果实不同部位维生素C和番茄红素含量测定

为了研究西瓜不同部位维生素C、番茄红素含量,对6个红瓤和1个黄瓤无籽西瓜品种果实不同部位总维生素C(TAA)、还原型维生素C(AA)、氧化型维生素C(DHAA)和番茄红素含量进行测定,并检测红瓤无籽西瓜整瓜贮藏2个月后各成分损失率。结果表明,不同无籽西瓜品种之间果实TAA、AA和DHAA及番茄红素含量差异显著;果实不同部位TAA、AA和DHAA及番茄红素含量也有很大差异,中间部位均大于近皮部。TAA、DHAA和番茄红素含量相关性达到极显著水平,AA和DHAA含量相关性达到显著水平。室温下整瓜贮藏2个月后果实不同部位TAA、AA、DHAA和番茄红素含量损失率为20%～50%。     

金桂及其芽变花色表型及色素成分分析

以金桂及其芽变花为试验材料,利用英国皇家园艺学会比色卡(Royal Horticultural Society Color Chart,R.H.S.C.C.)和色差仪测量两种花的颜色表型,通过显色法和紫外—分光光度计初步确定了两种花的主要色素类型,并且利用高效液相色谱—光电二极管阵列(HPLC–DAD)测定花瓣中类胡萝卜素和总黄酮含量,利用高效液相色谱—大气压化学电离源—质谱联用技术(HPLC–APCI–MS)和标准品鉴定主要类胡萝卜素成分。结果发现,芽变枝条上的花色由母本的黄色(R.H.S.C.C.12B~13A)变为橙红色,且花瓣边缘和内部颜色不同(内侧R.H.S.C.C.23B,花瓣外缘R.H.S.C.C.N25A);两种花瓣中均含黄酮类化合物,不含花青素苷,且两者的类胡萝卜素含量存在一定差异;从两种花瓣中分离鉴定出主要的类胡萝卜素成分为α–胡萝卜素和β–胡萝卜素,这两种组分和类胡萝卜素总量在芽变花瓣中极显著高于母本,而两种花瓣的总黄酮含量无显著性差异。因此,最终可以确定引起芽变花色变化的主要色素成分为类胡萝卜素。     

高效液相色谱法测定苹果果皮的类胡萝卜素

用高效液相色谱法测定苹果果皮多种类胡萝卜素。以丙酮与石油醚提取色素 ,用NovapakC18(4 .6mm×15 0mm)色谱柱 ,乙腈∶甲醇∶二氯甲烷 (70∶2 0∶10 )流动相 ,在 45 0nm下检测类胡萝卜素。结果表明 ,玉米黄质、叶黄素、番茄红素与 β 胡萝卜素的回收率分别是94.2 7%～ 99.82 %、84.5 6 %～ 89.41%、87.5 3～ 93.5 4%与 88.0 8%～93 .2 4%。其中富士果仅检测到玉米黄质 (5 .9× 10 -3 μg/mm2 )与 β 胡萝卜素 (5 .4× 10 -3 μg/mm2 ) ;蛇果 (红星 )只有玉米黄质 (9.1× 10 -3 μg/mm2 )。     

Transpiration efficiency of Amaranth (Amaranthus sp.) in response to drought stress

Drought is a major abiotic stress responsible for severe crop losses worldwide. Development of new crop varieties with increased drought tolerance is one way to increase crop productivity. The aim of this study was to characterise the diversity of nine accessions belonging to Amaranthus tricolor and A. cruentus, in response to drought stress using a dry-down protocol to characterise the transpiration efficiency (TE). Plants were subjected to either a gradual dry down or well-watered conditions. Results showed that TE was significantly higher (P < 0.01) in water-deficient (WD) plants compared to water-sufficient (WS) plants, 2.40 g kg^?1–7.13 g kg^?1 and 2.19 g kg^?1–4.84 g kg^?1, respectively. There was no significant difference in the fraction of transpirable soil water (FTSW) threshold decline between the amaranth genotypes. TE was highly correlated with yield under both WS (r = 0.89, P < 0.001) and WD conditions (r = 0.662, P < 0.001), and negatively correlated with root-to-shoot ratio under both WS (r = ?0.488, P < 0.05) and WD conditions (r = ?0.460, P < 0.05). Significant genotypic differences were seen for growth rate and stress susceptibility index (SSI). The result obtained in this investigation underline the need to identify genotypic variation in water use efficiency in amaranth.

Abbreviations: FTSW: Fraction of transpirable soil water; NTR: normalised transpiration rate; SSI: Stress susceptibility index; TE: transpiration efficiency; WHC: water holding capacity; WD: water-deficient; WS: water-sufficient.     

西瓜瓤类胡萝卜素研究进展

西瓜瓤颜色差异缘于所含类胡萝卜素种类与数量的不同。分析它们在不同品种西瓜中的组成,研究造成这种差异的遗传背景与色素的生物合成途径,可促进西瓜营养育种及其类胡萝卜素应用开发。西瓜类胡萝卜素分析最初是通过开放柱色谱法进行,当前多用高效液相色谱法,由于分辨率低或缺少标准样品,目前,2种方法都还得不到满意结果。色素分析结果表明,红色瓤西瓜主含番茄红素,橙黄色瓤主含ζ-胡萝卜素、前番茄红素与β-胡萝卜素,白色瓜含有六氢番茄红素、β-与ζ-胡萝卜素。基因型、染色体倍数、环境条件及果实成熟度影响西瓜中番茄红素含量。西瓜瓤颜色受几个基因控制,每个基因位点有2或3个等位基因。目前,已从西瓜中分离出类胡萝卜素合成途径几种酶的cDNA全长及基因片段。根据所发现的类胡萝卜素种类与基因分析结果,提出西瓜类胡萝卜素的可能生物合成途径。