Cytokinins and fruit development in the kiwifruit (Actinidia deliciosa). II. Effects of reduced pollination and CPPU application

The significance of changes in cytokinin content during early fruit growth was examined in the kiwifruit ( Actinidia deliciosa var. deliciosa cv. Hayward). Fruit growth was modified by the reduction of seed number or by the application of the synthetic phenylurea cytokinin N -(2-chloro-4-pyridyl)- N -phenylurea (CPPU). The influence of these treatments on cell division was monitored by flow cytometry and changes in the endogenous cytokinins were measured at days 10 and 20 after anthesis, using high-performance liquid chromatography and radioimmunoassay. Total cytokinin levels appeared not to be limiting growth since the highest total cytokinin concentration was detected in unpollinated fruit, which abscised by day 25 after anthesis. However, compared with control fruit which had the highest concentration of zeatin (Z) 10 days post anthesis, Z levels were low in unpollinated fruit. It is hypothesised that an increase in Z is the critical change in cytokinin metabolism required for the initiation of cell division and fruit growth. The synthetic cytokinin CPPU promoted fruit development, but there was a decrease in the endogenous cytokinin concentration. Zeatin was not detected in CPPU-treated fruit. Cell division was reduced in unpollinated fruitlets but there was no significant difference ( P > 0.05) between the other treatments. Differences in final fruit size appeared to be due to cell expansion.     

Role of Phenylurea Cytokinin CPPU in Apical Dominance Release in In Vitro Cultured Rosa hybrida L.

Abstract The effect of purine (BA) and phenylurea (CPPU) cytokinins on apical dominance release in in vitro cultured Rosa hybrida L., cv. Madelon and Motrea was evaluated. Cv. Madelon shows stronger natural apical growth and fewer branches than cv. Motrea in vivo and in vitro. We examined the effects under three conditions, without the addition of the auxin IBA, in the presence of IBA, and in material pretreated with a pulse of IBA. Results were scored weekly for 4 weeks. BA and CPPU stimulated axillary bud break, and higher numbers of open buds were recorded in the presence of CPPU. When CPPU cytokinin was added to culture medium, physiologic features such as bud sprouting and shoot fresh and dry weight were enhanced. CPPU was also highly efficient for overcoming IBA inhibition of bud outgrowth. Different cultivar responses were observed. Received 27 April 1999; accepted 23 February 2000     

四种植物生长调节剂对线纹香茶菜组织培养的影响

以线纹香茶菜叶切片、茎切段为外植体,研究2,4-D、NAA、6-BA、CPPU对其快速繁殖的影响。结果表明,0.2~0.3mg/L CPPU能诱导叶切片、茎切段两端切口处产生不定芽,平均诱导率分别为22.5%和66.0%,亦能使叶腋形成丛生芽;其活性高于相同浓度的6-BA。0.2mg/L CPPU与0.1mg/L NAA配比对无根苗的芽增殖效果最佳。在附加0.2mg/L NAA的1/2MS培养基上无根苗的生根效果最好。     

N-(2-氯-4-吡啶基)-N'-苯基脲(CPPU)对无疣墙藓原丝体发育与芽体发生的影响

0.2、0.4、1.0及1.5mg·L-1 4个浓度的N-(2-氯-4-吡啶基)-N'-苯基脲(CPPU)对无疣墙藓的孢子萌发没有显著影响,但抑制绿丝体伸长和侧枝生成,对芽体的分化有明显的促进,且芽体发生数随浓度升高而增加.     

Response of sucrose metabolizing enzyme activity to CPPU and p-CPA treatments in excised discs of muskmelon

We investigated the effects of 1-(2-chloro-4-pyridyl)-3-phenylurea(CPPU) and para-chlorophenoxyacetic acid(p-CPA) treatments on the sucrose metabolism-relatedenzymeactivities in excised mesocarp discs of muskmelon fruit at different growthstages. Both a CPPU and a p-CPA treatment applied to discsprepared at 5 and at 20 days after anthesis (DAA) increased acid invertase (AI)activity and neutral invertase (NI) activity, but neither treatment affectedthese activities in the discs prepared at 45 DAA. Both plant growth substancesincreased the activity of sucrose phosphate synthase (SPS) in the discs at 5and20 DAA, but neither affected it in the 45 DAA discs. The sucrose synthase (SS)activity was markedly increased by p-CPA treatment in the20 and 45 DAA discs, but was not affected at 5 DAA. CPPU treatment did notactivate SS of discs throughout the growth stage.     

CPPU提高柚树苗抗旱性的研究

水分胁迫下,柚树苗叶片RWC、ψw、Pn及可溶性蛋白质,叶绿素含量下降,游离脯氨酸、MDA含量及SOD活性升高,CAT活性先上升后下降,APX活性、AsA和GSH含量明显下降,抗旱性强的品种具有较高的活性氧清除能力。CPPU处理提高柚树苗叶片RWC、Pn、叶绿素、游离脯氨酸、AsA、GSH含量,并增加SOD、APX活性,降低MDA水平,从而提高柚树苗抗旱性。实验结果表明,CPPU处理提高叶片对膜脂过氧化作用的保护能力可能是其提高柚树苗抗旱性的原因。     

Gibberellins Increase Cuticle Deposition in Developing Tomato Fruit

Effects of the gibberellins A₄₊₇(GA₄₊₇) and A₃(GA₃), benzyladenine (BA) and forchlorfenuron (CPPU) on deposition of the cuticular membrane (CM) in developing tomato (Lycopersicon esculentum L.) fruit were investigated. Growth regulators were applied when fruit development within trusses ranged from the flower to the mature stage. Developmental stage of fruit at the time of application was indexed by fruit diameter. Fruit were harvested at maturity, the CM isolated enzymatically on an individual fruit basis and mass of CM per unit fruit surface area calculated. In mature fruit, mass of CM per fruit increased with fruit size, but mass of CM per unit surface area was independent of fruit size, position within a truss and position of the truss on the plant. GA₄₊₇ and GA₃ increased CM mass per unit fruit surface area at concentrations up to 300 mg l⁻¹. Young fruit (5–10 mm diam. at time of application) was most responsive. Responsiveness decreased as fruit development at application progressed towards maturity. There was no consistent effect of GA₄₊₇ or GA₃ on fruit mass. BA (up to 100 mg l⁻¹) or CPPU (up to 3 mg l⁻¹) had no significant effect on CM mass per unit surface area regardless of developmental stage. Higher concentrations of BA or CPPU decreased CM mass per unit surface area. There was no effect of BA or CPPU on fruit mass. Potential mechanisms and benefits of a gibberellin induced increase in CM deposition are discussed.     

CPPU处理对猕猴桃果实品质的影响

以猕猴桃(Actinidia)品种‘东红’和‘金玉’为材料,在果实发育不同时期用20 mg/L的氯吡脲(CPPU)浸果处理,比较不同实验组的果重、可溶性固形物含量、糖含量、酸含量、Vc含量和花青素含量等果实品质的差异,探讨CPPU处理的最佳时期;并在‘东红’和‘金玉’的CPPU处理组和对照组中,采用实时荧光PCR技术(RT-qPCR)分析花青素相关基因的表达水平,探究CPPU调控花青素积累的分子机理。结果显示,花后14 d(14 DAF)为CPPU处理‘东红’的最佳时期,处理后单果重提高了24%,总糖含量提高了38%。相关性分析表明,果重与花青素含量成正相关。‘金玉’果实经CPPU处理后内果皮并未出现明显变化。‘东红’果实经处理后,其花青素含量显著提高,内果皮颜色更加红艳。RT-qPCR分析结果发现,CPPU处理后花青素合成相关基因AcF3GT、AcF3H、AcLDOX、AcMYB10和AcMYB110表达量上调,促进花青素的积累。研究结果表明CPPU处理能提升‘东红’和‘金玉’猕猴桃果实品质,处理‘东红’猕猴桃的最佳处理时期是花后14 d。CPPU处理导致上述5个基因表达水平提高,从...     

Study on russet-related enzymatic activity and gene expression in ‘Shine Muscat’ grape treated with GA3 and CPPU

Physiological (metabolite analysis) and molecular (gene expression) approaches were used to understand the mechanism underlying russet formation in response to the application of GA₃ and CPPU (Forchlorfenuron) in a Japanese table grape cultivar ‘Shine Muscat’. Several different concentrations of GA₃ and GA₃?+?CPPU [25?mg?L^?1 GA₃ (A), 25?mg?L^?1 GA₃?+?5?mg?L^?1 CPPU (B), 25?mg?L^?1 GA₃?+?10?mg?L^?1 CPPU (C), and 25?mg?L^?1 GA₃?+?15?mg?L^?1 CPPU (D)] were applied to grape berry clusters at two weeks after flowering (WAF). No russet was observed on the berries treated with the ‘C’ combination. Lower levels of phenylalanine ammonia-lyase (PAL) activity was observed in the treated samples, relative to the untreated material. Reduced peroxide (POD) activity was also observed in response to different treatments, while the expression of Peroxidase 17 and Phenylalanine ammonia-lyase G1 genes mirrored lignin content. Increased activity of 4-coenzyme A ligase (4CL) may contribute to decreasing the level of russet and help to improve grape berry quality.     

CPPU和6-BA对盐胁迫下番茄活性氧代谢及叶绿素荧光的影响

以番茄品种 '金棚一号' 幼苗为材料,通过营养液水培试验,研究了不同浓度(10、20、30 mg·L-1)外源细胞分裂素N-苯基-N'-(2-氯-4-吡啶基)脲(CPPU)和6-苄基腺嘌呤(6-BA)对NaCl胁迫下番茄幼苗活性氧代谢及叶绿素荧光的影响.结果表明,NaCl胁迫处理导致番茄幼苗活性氧生成速率和过氧化物酶(SOD)、超氧化物岐化酶(POD)和过氧化氢酶(CAT)活性显著增加,但抗氧化酶活性的提高幅度低于活性氧的积累速度,最终导致番茄幼苗光合系统Ⅱ(PSⅡ)能力降低;营养液添加CPPU和6-BA在一定程度上均可缓解NaCl对番茄幼苗的伤害,但存在明显浓度效应,其中20 mg·L-1 CPPU处理效果最好,其次为30 mg·L-16-BA处理;在20 mg·L-1 CPPU和30 mg·L-16-BA处理下,番茄幼苗叶片和根系O2产生速率、MDA含量显著低于NaCl处理,而SOD、POD、CAT活性和光合性能却显著提高.研究发现,CPPU和6-BA均通过诱导提高番茄幼苗抗氧化酶活性来缓解NaCl胁迫对其细胞膜的伤害和对光合的抑制,但CPPU缓解效果更好且最适浓度较低.