柑橘果皮颜色的形成与类胡萝卜素组分变化的关系

分析了果皮分别为红、橙和黄颜色的柑橘品种“满头红”、“尾张”和“胡柚”果实着色过程中果皮类胡萝卜素组分及含量的变化。结果表明,随着果实的发育和成熟,果皮叶绿素含量下降,α-胡萝卜素、β—胡萝卜素含量逐渐下降直至消失,而β—隐黄质、β-柠乌素、玉米黄质等叶黄素成分含量逐渐上升,果实逐渐褪绿并呈现其特征色泽。“胡柏”果皮中类胡萝卜素总量及其橙、红色类胡萝卜素成分β-隐黄质和β-柠乌素积累少是其颜色淡、呈黄色的主要原因;三种果实的颜色差异并非由于果皮类胡萝卜素总量的差异,而主要是由于果皮不同类胡萝卜素成分组成比例不同。“满头红”以积累红色的β-柠乌素为主,而“尾张”则以积累橙色的β-隐黄质为主。     

MPTA对柑橘果皮类胡萝卜素形成的影响

以宽皮柑橘“本地早”为试材 ,研究了 2 (4 甲基苯氧 )三乙基胺 (MPTA)处理对柑橘果实外观颜色的影响 ,并探讨其与相关类胡萝卜素消长的关系及与糖含量变化的可能联系。结果表明 :MPTA处理促进柑橘果皮组织中类胡萝卜素 (主要为番茄红素 )的生物合成 ,使果皮颜色由淡橙黄色转为红色 ;随着番茄红素的积累 ,其上游前体物质葡萄糖含量下降 ,而其下游产物β 隐黄质、玉米黄素的合成不受影响     

宁夏枸杞果实遮光处理对果实糖积累和相关酶活性的影响

在宁夏枸杞盛花期对果实进行遮光处理,以自然照光为对照,通过测定枸杞果实生长指标、果实叶绿素含量、蔗糖代谢糖分含量及其蔗糖代谢相关酶活性,以研究枸杞果实光合作用在枸杞果实糖积累中的效应及对枸杞果实多糖和总糖含量积累的影响。结果表明:(1)遮光后,果实单粒重和果实中叶绿素含量均降低,体积却有所增加,遮光处理主要影响果实着色期和成熟期的糖含量,对果实发育初期影响不大;(2)遮光处理不同程度增加了果实转化酶、蔗糖磷酸合成酶和蔗糖合成酶活性。枸杞果实多糖的形成与果实光照具有一定的关系,而总糖含量的积累与光照关系不大。     

柑橘果实遮光处理对发育中的果实光合产物分配、糖代谢与积累的影响

研究了柑橘果实膨大初期遮光处理对果皮色素、果实含糖量、光合产物在果实内的分配及果实中蔗糖代谢相关酶活力变化的影响.结果表明遮光处理使果皮中的叶绿素含量迅速降低而类胡萝卜素积累缓慢,蔗糖的相对含量则明显上升.遮光处理还促进了光合产物向果皮运输,相应地降低了汁囊中光合产物分配比率,使果实汁囊中蔗糖含量下降.果皮中SS、SPS和转化酶活力在遮光处理后均有较大的提高,而汁囊中则差异不大.上述结果表明,在果实自身光合作用被抑制的条件下,果皮是通过提高酶活力来增强库强度,从而使其在与汁囊竞争中获得更多的光合产物,造成汁囊含糖量下降.     

柑橘果实遮光处理对发育中的果实光合产物分配、糖代谢与积累的影响

研究了柑橘果实膨大初期遮光处理对果皮色素、果实含糖量、光合产物在果实内的分配及果实中蔗糖代谢相关酶活力变化的影响。结果表明：遮光处理使果皮中的叶绿素含量迅速降低而类胡萝卜素积累缓慢,蔗糖的相对含量则明显上升,遮光处理还促进了光合产物向果皮运输,相应地降低了汁囊中光合产物分配比率,使果实汁囊中蔗糖含量下降。果皮中SS、SPS和转化酶活力在遮光处理后均有较大的提高,而汁囊中则差异不大。上述结果表明,在果实自身光合作用被抑制的条件下,果皮是通过提高酶活力来增强库强度,从而使其在与汁囊竞争中获得更多的光合产物,造成汁囊含糖量下降。     

遮光灵武长枣果实糖积累和代谢相关酶活性特征

于灵武长枣盛花期对果实进行遮光处理,以自然照光为对照,通过测定果实生长指标、叶绿素含量、蔗糖代谢相关酶活性及其蔗糖代谢糖分含量等,研究果实光合作用在果实糖积累中的作用及对果实多糖和总糖含量积累的影响。结果表明:(1)遮光处理后,果实单粒重、单粒体积以及果实中叶绿素含量均降低。(2)遮光处理不同程度增加了果实中转化酶、蔗糖磷酸合成酶和蔗糖合成酶分解方向酶的活性,而降低了其蔗糖合成酶合成方向酶的活性。(3)遮光处理主要影响果实着色期和成熟期的糖含量,对果实发育初期糖含量影响较小;果实多糖的形成与果实所受光照状况具有一定的关系,而果实中总糖的积累与外界光照具有密切关系。可见,果实遮光处理影响了果实发育过程中蔗糖代谢相关酶的活性,从而影响果实糖分的代谢和积累。     

桃果实发育阶段肉色形成与类胡萝卜素的变化分析

为了分析不同肉色类型桃果实发育过程中类胡萝卜素成分的变化特点及其颜色差异形成的因素,选择‘半斤桃’(红肉)、‘图八德’(黄肉)、‘正姬’(白肉)桃品种为试材,采用紫外分光光度计和高效液相色谱法(HPLC)对桃果实类胡萝卜素及其组分含量进行定性定量分析.结果显示:(1)桃果实的主要类胡萝卜素成分为叶黄素、玉米黄素、β-隐黄质、α-胡萝卜素和β-胡萝卜素.(2)随着果实的发育,‘半斤桃’和‘正姬’的类胡萝卜素总含量逐渐降低,而‘图八德’则是先降低后上升,且明显高于前二者;3种类型桃果实的叶黄素均逐渐降低,果实成熟时接近0;玉米黄素呈先降后升的趋势,果实成熟时达到最大值;‘半斤桃’和‘正姬’的β-隐黄质、α-胡萝卜素和β-胡萝卜素呈逐渐下降的趋势,而‘图八德’的β-隐黄质含量先升后微降最后上升、α-胡萝卜素和p-胡萝卜素含量则逐渐增加,且均在果实成熟时达到最大值.(3)‘图八德’成熟果实中的类胡萝卜素总含量达到最大值,其中β-胡萝卜素含量最高,占5个成分之和的75.99％.研究表明,桃果实肉色形成与类胡萝卜素的含量与成分有着紧密的联系,尤其是其中的β-胡萝卜素含量.     

套袋对苹果发育过程中果皮色素及果肉糖含量的影响

以富士苹果'长富2号'品系为试材,研究了套袋后果实生长发育过程中果皮色素含量、果肉糖含量及取袋后果皮色素、糖含量和PAL活性等品质形成因子的变化规律.结果显示:套用双层纸袋能显著降低红富士苹果果皮叶绿素含量,并以叶绿素a降低幅度较大,且与总叶绿素含量呈基本一致的下降变化趋势,而果皮类胡萝卜素降低幅度较小;果皮的花青苷含量取袋前显著低于对照,取袋后迅速上升,并在取袋后6 d超过对照,采收时超过对照1倍以上;果实PAL酶活性取袋后呈先升后降的趋势,取袋后4 d活性超过对照,取袋后6 d活性达到最高值;套袋不同程度地降低了果实可溶性总糖和还原糖含量,取袋后可溶性总糖、果糖和葡萄糖含量上升,蔗糖含量在取袋后4 d内迅速上升而后下降,但套袋果始终低于对照果.研究表明,套袋可以显著降低果皮中叶绿素的含量,促进花青苷积累,从而减少叶绿素对果实着色的干扰,提高果实外观品质,但同时也部分减少了果实总糖的含量,对果实内在品质有一定负面影响.     

辣椒果实类胡萝卜素生物合成研究进展

辣椒是全世界广泛栽培的蔬菜作物之一,成熟的辣椒果实中含有α-胡萝卜素、β-胡萝卜素、玉米黄质、叶黄素、隐黄质、辣椒红素及辣椒玉红素等多种不同的类胡萝卜素;由于类胡萝卜素生物合成途径存在差异调控方式,最终在辣椒果实中积累不同成分和含量的类胡萝卜素,从而导致不同辣椒果实颜色的形成。同时,辣椒果实含有的各种类胡萝卜素因具有重要保健及经济价值,也越来越受到育种家重视。本文系统概述了辣椒果实颜色与类胡萝卜素组分、类胡萝卜素生物合成途径、关键酶基因的功能及相关转录调控机制等方面的研究进展,总结了当前研究中存在的问题,并提出相应的研究展望,对今后高类胡萝卜素辣椒新品种选育、人为调控类胡萝卜素生物合成、改善辣椒果实品质具有重要的意义。     

柑橘果实的光合特性、产物运输及分配在糖分积累中的作用

测定了温州蜜柑 (CitrusunshiuMarc .cv .Miyagawawase)果实发育进程中干鲜重、果皮光合速率和叶绿素含量的变化 ,并用14 CO2 示踪技术研究了果皮和叶同化生成的光合产物在果实内的运输分配特性。结果表明 :果皮光合速率与叶绿素含量有关 ,随着叶绿素含量的下降 ,果实光合速率也快速下降。在果实完熟之前 ,即使是当果皮积累的干重超过汁囊时 ,叶同化产物仍主要分配到汁囊中 ;而在完熟阶段 ,果皮光合速率接近零 ,果皮成了叶同化产物的主要库。果皮的同化产物 ,主要保留在果皮中 ,输入到汁囊的比率随果实发育而下降 ,但高峰时也有 12 %输入汁囊。与对照相比 ,果实遮光处理后降低了果皮与汁囊的干重和含糖量。上述结果表明果皮光合产物主要用于果皮自身的发育并能减少对叶光合产物的依赖 ,同时也能部分增加汁囊糖的积累     

Patterns of pigment changes in apple fruits during adaptation to high sunlight and sunscald development

Reflectance spectra of four apple (Malus domestica Borkh.) cultivars were studied and chlorophyll, carotenoid, anthocyanin and flavonoid content in sunlit and shaded peel was determined. In all cases sunlit peel accumulated high amounts of phenolics (flavonoid glycosides). Adaptation to strong sunlight of an apple cultivar with limited potential for anthocyanin biosynthesis (Antonovka) was accompanied by a decrease in chlorophyll and a significant increase in total carotenoid content. The increase in carotenoids also took place in sunlit sides of the Zhigulevskoye fruits, accumulating high amounts of anthocyanins, but chlorophyll content in sunlit peel was higher than that in shaded peel. Significant increases in carotenoids and anthocyanins were detected during fruit ripening when chlorophyll content fell below 1.5–1.8 nmol cm^–2. Chlorophyll in sunlit fruit surfaces of both cultivars was considerably more resistant to photobleaching than in shaded (especially of Zhigulevskoye) sides. Induced by sun irradiation, the photoadaptive responses were cultivar-dependent and expressed at different stages of fruit ripening even after storage in darkness. The development of sunscald symptoms in susceptible apple cultivars (Granny Smith and Renet Simirenko) led to a dramatic loss of chlorophylls and carotenoids, which was similar to that observed during artificial photobleaching. The results suggest that apple fruits exhibit a genetically determined strategy of adaptation of their photoprotective pigments to cope with mediated by reactive oxygen species photodynamic activity of chlorophyll under strong solar irradiation. This includes induction of synthesis and accumulation of flavonoids, anthocyanins and carotenoids that could be expressed, if necessary, at different stages of fruit development     

Physiological changes associated with senescence and abscission in mature citrus fruit induced by 5-chloro-3-methyl-4-nitro-1H-pyrazole and ethephon application

This research compares effects of the compound 5-chloro-3-methyl-4-nitro-1 H -pyrazole (CMNP), a plant growth regulator that selectively promotes abscission in mature citrus fruit ( Citrus sinensis ), and the ethylene-releasing agent ethephon (2-chloroethylphosphonic acid). Application of CMNP and ethephon to mature citrus fruit reduced fruit detachment force and changed peel color from green to orange. More total chlorophyll was extracted from flavedo in early season (November) than late season (January), and both compounds caused a similar reduction in chlorophyll. In contrast, total carotenoid content was similar in November and January. Both abscission compounds increased total carotenoids, but induction was greater in January, and CMNP was more effective in both months. Phospholipase A₂ (PLA₂) activity increased after CMNP but not ethephon application. Electrolyte leakage increased 2 h after CMNP treatment, and total protein content was reduced by 50% after 72 h. Ethephon caused only minor changes in electrolyte leakage and total protein content. Inhibition of PLA₂ activity with aristolochic acid did not reduce leakage but inhibited total protein loss and reduced visual peel damage associated with CMNP. Ultrastructural observations indicated decreased number, and length of starch grains 3 h after CMNP treatment. A transient increase in soluble sugars was measured 3 h after CMNP application. Ethephon had little effect on soluble sugar content and changes in starch grains. Collectively, the results indicate that CMNP and ethephon induced color change in peel and advanced mature fruit abscission. However, CMNP but not ethephon promoted other physiological changes associated with senescence.     

分株比例对异质光环境下美丽箬竹克隆系统光合生理的影响

分株数量或生物量比例差异会明显影响克隆系统对资源异质性环境的生态适应性, 地下茎木质化、连接稳固的竹类植物在生长过程中相连克隆分株通常会生活在异质光环境中, 但其叶片光合生理特性对异质光环境的响应及其分株比例效应则未见报道。该研究以地下茎相连的美丽箬竹(Indocalamus decorus)克隆系统为实验材料, 设置2个遮光率(分别为50% ± 5%和75% ± 5%)和3个分株比例(遮光与未遮光分株比例分别为1:3、2:2、3:1)处理, 分株数量为4株。分别测定了遮光处理后30、90、150天遮光和未遮光分株叶片光响应特征、气体交换参数、光合色素含量, 分析了异质光环境下美丽箬竹光合生理的变化规律。结果显示: 分株比例对美丽箬竹光合生理有显著影响, 且其与遮光、处理时间交互作用显著。美丽箬竹克隆系统遮光分株比例越大, 即遮光相对分株数量越多, 其表观量子效率(AQE)、光饱和点、最大净光合速率(P_{n max})、净光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)、水分利用效率越大, 光补偿点、暗呼吸速率越小, 其光合效率越高, 光能利用能力越强, 而与之相连的未遮光分株则相反; 随遮光分株比例的增大, 遮光分株叶片叶绿素a、叶绿素b含量呈先升高而后下降的变化趋势, 类胡萝卜素(Car)含量则持续下降, 而与之相连的未遮光分株叶片光合色素含量则呈下降趋势; 遮光率提高, 相同分株比例美丽箬竹克隆系统遮光分株叶片AQE、P_{n max}、P_n、G_s、胞间CO₂浓度(C_i)和光合色素含量总体升高, 而与之相连的未遮光分株叶片P_{n max}、C_i以及Car含量则总体下降。研究结果表明异质光环境下, 遮光分株光合效率和弱光利用能力明显增强, 而未遮光分株则相反, 克隆系统内分株间发生了明显的克隆分工, 且2:2、3:1分株比例克隆系统较1:3分株比例对异质光环境具有更好的适应能力。美丽箬竹克隆系统可通过差异性调节分株光合生理特性和光合色素含量, 提高遮光分株光能利用和光合效率来适应异质光环境, 以提高克隆系统的适合度。     

不同生长阶段遮荫对番茄光合作用、干物质分配与叶N、P、K的影响

对番茄植株做了两种不同程度的遮荫处理,观测了夏季午间遮荫对光合速率,干物质积累量及其在根,茎,叶之间的分配,和叶N,P,K的含量以及经济产量的影响,发现不同时期遮荫影响不同。（1）遮荫增加三个阶段（开花早期,盛花期和开花后期）的气孔导度和胞间CO2浓度,显著降低开花早期中午的净化合速率,但盛花期中度遮荫（40%遮荫）使净光合速率随着时间的增加逐渐上升,在开花后期表现更加明显,平均净光合速率比对照高20%以上,蒸腾速率也增加较多。（2）开花早期和盛花期重度遮荫（如本实验中的75%遮荫）显著降低根,茎的干重,而开花后期中度遮荫的根,茎干重高于对照,但遮荫对叶干重的影响不明显。（3）开花早期和盛花期遮荫不明显影响叶片中N,P,K的含量,但开花后期中度遮荫使N,P,K含量增加,（4）开花早期两种遮荫对果实产量影响较小,但盛花期重度遮荫使产量降低,全部产量中无效部分所占的比例上升,开花后期中度遮荫的总产量和有效产量增加,单果重也增加,这些结果表明,在某些时期中度遮荫可以克服夏天辐射过强,气温过高对番茄的不良影响,对番茄生长,干物质积累和提高产量等有利,在生产上有意义。     

In vivo sucrose stimulation of colour change in citrus fruit epicarps: Interactions between nutritional and hormonal signals

During ripening, citrus fruit-peel undergoes 'colour break', a process characterized by the conversion of chloroplast to chromoplast. The process involves the progressive loss of chlorophylls and the gain of carotenoids, changing peel colour from green to orange. In the present work, the in vivo and in vitro effects of supplemented nutrients (sucrose and nitrogen) and phytohormones (gibberellins [GA] and ethylene) on colour change in fruit epicarp of Satsuma mandarin ( Citrus unshiu (Mak.) Marc., cv. Okitsu), were studied. The rate of colour break was correlated positively with sucrose content and negatively with nitrogen content. The removal of leaves blocked natural sucrose build-up and nitrogen reduction in the peel. Defoliation also inhibited chlorophyll disappearance and carotenoid accumulation, thereby preventing colour break. In vivo sucrose supplementation promoted sucrose accumulation and advanced colour break. In both in vivo and in vitro experiments, colour change promoted by sucrose was unaffected by ethylene but delayed by GA_3. In non-supplemented plants, ethylene accelerated colour break while GA₃ had no detectable effects. Ethylene inhibitors effectively counteracted the sucrose effects on colour change. Collectively, these results suggest that the chloroplast to chromoplast conversion in citrus fruit epicarps is stimulated by sucrose accumulation. The sugar regulation appears to operate via ethylene, whereas GA may act as a repressor of the sucrose-ethylene stimulation.     

外源ABA和GA3对红肉脐橙果皮主要色素含量变化和果实着色的影响

测定了红肉脐橙(Citrus sinensis Osbeskcv.CaraCara)果实发育期间和果实转色前用不同浓度的外源ABA和GA₃处理后果皮叶绿素和类胡萝卜素的动态含量,并测定了外源ABA和GA₃处理后成熟红肉脐橙果皮色泽的表现。结果表明:红肉脐橙果皮叶绿素含量于9月20日出现最大值,为0.1469mg·g^-1FW;类胡萝卜素含量于12月20日达到最大值,为0.0321mg·g^-1FW;果实转色前,用外源ABA处理后加速了果皮叶绿素的降解,但也抑制了果皮类胡萝卜素的积累,用GA₃处理后延缓了果皮叶绿素的降解,同样抑制了果皮类胡萝卜素的积累,严重阻碍了果皮类胡萝卜素的合成;外源ABA或GA₃处理均不利于果实色泽品质的提高。