Paclobutrazol induces the concurrent accumulation of chrysolaminarin and lipids in the diatom Phaeodactylum tricornutum

Paclobutrazol is a plant growth regulator and inhibitor of endogenous gibberellin synthesis.It is a powerful inhibitor of vegetative growth by changing the photosynthetic rate and plant hormone levels,thereby affecting plant growth and development.In this study,the effects of paclobutrazol on the model diatom Phaeodactylum tricornutum were investigated.Results show that 2.5-mg/L and 10-mg/L paclobutrazol significantly inhibited the algal growth by inhibiting chlorophyll synthesis,which affects photosynthesis.The antioxidant system,including catalase(CAT)and glutathione peroxidase(GPx)was severely damaged.Chrysolaminarin content was significantly elevated and doubled up to 127 mg/g dry cell weight(DCW)by 10-mg/L paclobutrazol treatment.In combination with transcriptomic analysis,paclobutrazol was demonstrated to play a regulatory role in the accumulation of chrysolaminarin and neutral lipids.

Effects of paclobutrazol application on plant architecture,lodging resistance,photosynthetic characteristics,and peanut yield at different single-seed precise sowing densities

The key to high-yielding peanut cultivation is the optimization of agricultural production practices.Regulating single-seed precise sowing(SSPS)density and paclobutrazol(Pbz)application concentration are effective practices that increase peanut yield by improving plant architecture,lodging resistance,and photosynthetic characteristics.Therefore,we conducted a two-factor field optimization experiment for the sowing density(D1:1.95×10^(5)plants ha^(-1),D52:2.40×10plants ha^(-1),D3:2.85×10^(5)plants ha^(-1),and D4:3.30×10^(5)plants ha^(-1))and Pbzapplication concentration(P0:0 mg L^(-1)and P1:100 mg L^(-1)).The objective was to optimize agricultural production practices and provide a theoretical basis for highyielding peanut cultivation by evaluating the effects of sowing density and Pbzapplication on plant architecture,lodging resistance,photosynthetic characteristics,and yield.The results showed that at the same Pbzapplication concentration,increasing sowing density increased lodging percentage and reduced leaf photosynthetic capacity.At the same sowing density,Pbzapplication reduced lodging percentage by decreasing plant height(PH),improving lignin biosynthesis-related enzyme activities,and enhancing stem puncture strength(SPS)and breaking strength(SBS).The paclobutrazol-induced alterations in plant architecture and lodging resistance improved light transmission at the middle and bottom leaf strata,resulting in the increase in relative chlorophyll content and net photosynthetic rate(Pn)of leaves.Furthermore,D3P1treatment had the highest peanut yield among all treatments.In summary,the production strategy combining the sowing density of 2.85×10^(5)plants ha^(-1)with the application of100 mg L^(-1)Pbzwas found to be the optimal agricultural production practice for giving full play to production potential and achieving higher peanut yield.

Effects of Different Concentrations of Paclobutrazol on Seedling Quality of Small Seedless Watermelon in Autumn

[Objectives]The paper was to explore the effects of different concentrations of paclobutrazol on seedling quality of small seedless watermelon in autumn.[Methods]The leaves of watermelon seedlings were sprayed with 30,50,80 and 120 mg/L paclobutrazol at cotyledon expansion stage,and those sprayed with tap water were used as control.[Results]All the treatments of paclobutrazol effectively inhibited the excessive growth of watermelon at seedling stage,significantly enhanced the leaf quality of watermelon seedlings and promoted root growth.The seedlings treated by 50 mg/L paclobutrazol had the best performance compared with the control:a decrease of hypocotyl by 37.9%,an increase of plant dry weight by 46.55%,significantly increased seedling strength index,deep green leaf color,thick leaves,an increase of specific leaf weight by 28.13%,and significantly heavier root weight and longer length.[Conclusions]The results will provide a reference for strong seedling cultivation of small seedless watermelon.

低营养条件下Paclobutrazol(PP333)对黄瓜去顶幼苗直接形成花芽的影响(简报)

植物开花机理是生物学中的一个基本问题,多年来人们进行过许多的研究,积累了大量的事实,然而对开花的机理仍然还不甚清楚。因而在利用原有实验系统的同时,有必要寻找更多简单,又便于分析的实验系统。Jullien等报告离体培养的大豆子叶节能直接产生花芽。我们在建立离体培养黄瓜子叶直接单独形成雄花或雌花的实验系统的过程中,发现黄瓜幼苗去除顶芽后在子叶节处也能直接形成花芽。

Effects of paclobutrazol on biomass production in relation to resistance to lodging and pod shattering in Brassica napus L.

Paclobutrazol was sprayed at 0, 150, and 300 mg L-1 during the closed canopy stage and the early bud stage with two high-yielding cultivars of rapeseed, Yangguang 2009 and Fengyou 520. The impact of paclobutrazol on the accumulation and distribution of biomass and its relationship with yield, resistance to lodging and pod shattering were determined. All the treatments increased the resistance as well as yield. The maximum yield was obtained when paclobutrazol was applied during the closed canopy stage at 150 mg L-1. The plant＇s resistance to both lodging and pod shattering was the maximum when paclobutrazol was applied during the early bud stage at 300 mg L-1. Paclobutrazol also delayed senescence, with the higher concentration or later spraying leading to more obvious effects; improved the net assimilation rate before the early bud stage; and promoted the relative growth rate of the main growth organ at each stage of growth and maximized the rate and quantities of biomass accumulation. However, at the higher concentration and later spraying, the increments were smaller. The spraying also increased the rates of biomass allocation to roots, leaves, and pods, but the rate of allocation to stems decreased as the plants grew shorter. The higher allocation to roots and the lower allocation to stems favoured resistance to both lodging and pod shattering whereas higher allocation to leaves and pods favoured yield. The higher concentration or late spraying led to excessive biomass being allocated to roots, which decreased leaf biomass during the bud stage, leading to greater resistance but lower yields.

PP333(Paclobutrazol)和S3307(Uniconazole)对盆栽榕树(Ficus microcarpa)的生理效应

用PP333和S3307处理盆栽榕树实生苗,两者都可以显著抑制其茎的伸长生长,使其株型矮化,叶片小型化,根冠比值增大,从而使盆栽榕树更符合盆景栽培的要求,PP333和S3307都能使盆栽榕树叶片的过氧化物酶活性提高,叶绿素含量和光合作用强度增加,在每平方米有效成分30～120mg的剂量范围内,PP333和S3307抑制盆栽榕树茎伸长生长等方面的生理活性,随剂量增加而增加,而S3307的生理活性明显强于PP333,添加GA_3,可以解除PP333和S3307对盆栽榕树茎伸长生长的抑制,将PP333施入盆栽榕树根际土壤或喷布于叶片表面,以前一种方法抑制盆栽榕树茎的伸长生长等方面的生理活性更强。

Effects of Paclobutrazol on Physiological Parameters of Dahlia under Heat Stress

[Objectives] This study was conducted to investigate the effect of paclobutrazol （PBZ） on heat tolerance of dahlia.[Methods] A dahlia variety Danbanhuang was selected as the experimental material in this study. After 100, 200, 300 or 400 mg/L paclobutrazol was sprayed evenly to the leaves of dahlia seedlings, they were cultured in an incubator at high temperature （35 ℃/30 ℃, day/night） for two days, and then transferred to an incubator at normal temperature （25 ℃/20 ℃, day/night）. The physiological and biochemical parameters of the dahlia seedlings were measured before exposure to high temperature （D0）, after exposure to high temperature for two days （D2） and exposure to normal temperature for one day （R1）.[Results] Compared to the negative control, foliar application of paclobutrazol decreased the content of MDA, increased the contents of chlorophyll, proline, soluble protein, and the activity of SOD, POD and CAT in dahlia plants under heat stress. The contents of MDA, soluble protein and proline in PBZ treated dahlia plants increased when they were subject to high temperature stress （35 ℃/30 ℃, day/night）, and then decreased when the temperature returned to normal （25 ℃/20 ℃, day/night）, and CAT activity decreased at high temperature, and then increased at normal temperature, while the activity of SOD and POD kept rising during the entire experimental period.[Conclusions] Foliar application of paclobutrazol can alleviate the adverse effect caused by high temperature to dahlia plants, and the experimental data provide a theoretical basis for the application of paclobutrazol in dahlia cultivation in South China.

Effects of Seed Soaking with Paclobutrazol on Tillering and Physio-logical Characteristics of Sugarcane Seedlings

In order to study the effects of seed soaking with Paclobutrazol( PP333) on the tillering and physiological characteristics of sugarcane seedlings,sugar cane variety ROC22 was used as experimental material. The effects of seed soaking with different concentrations of PP333 were studied. The tiller number and growth of sugarcane were surveyed at the 6-leaf stage,the physiological indicators such as chlorophyll content,soluble protein content,proline content and peroxidase activity were measured at the 2-leaf,4-leaf,and 6-leaf stages. The results showed that the seed soaking with PP333 can effectively improve the tillering of sugarcane seedlings. The suitable concentration for the tillering of sugarcane and the growth and development of sugarcane was of 50 mg/L; the seed soaking with PP333 significantly increased the chlorophyll,soluble protein,proline,and peroxidase activity of leaves of sugarcane seedlings; the content of chlorophyll and soluble protein in leaves of sugarcane seedlings treated with 90 mg/L PP333 was the highest,and the proline content and peroxidase activity of sugarcane treated with 50 mg/L PP333 were the highest.

Effects of Biological Fertilizer and Paclobutrazol on Total Flavonoids in Ophiopogon japonicus

[Objectives] The research aimed to study the effects of applying biofertilizer instead of paclobutrazol on the content of flavonoids in Ophiopogon japonicas and determine its quality characteristics,in order to provide the scientific basis for the quality control of GAP and the comprehensive utilization of resources. [Methods] O. japonicas collected in Lingxing Town and Huayuan Town of Sichuan Province was divided into three groups: blank control group,paclobutrazol group and biofertilizer group. Root tuber of O. japonicas was obtained,and the enzyme was killed by the microwave,and then it was dried in 60℃. The content of flavonoids in root tuber of O. japonicus was determined by ultraviolet spectrophotometry. Then,SPSS19. 0 was used to analyze the results. [Results]The average contents of flavonoids in different treatments were as follows: 0. 184%-0. 198% in control group; 0. 283%-0. 330% in the paclobutrazol group; 0. 404%-0. 428% in the biofertilizer group. Biological bacterial fertilizer had a significant role in promoting the synthetic accumulation of homoisoflavonoids in O. japonicus( P <0. 001**). [Conclusions]The application of biological fertilizer can not only significantly improve the content of homoisoflavonoids in root ruber of O. japonicus,but also significantly optimize the micro ecological environment of soil. Therefore,biofertilizer should be widely used to gradually replace paclobutrazol in the main production areas of O. japonicas.

Transcriptomic and proteomic analyses of far-red light effects in inducing shoot elongation in the presence or absence of paclobutrazol in Chinese pine

In angiosperms, low red (R)/far-red (FR) ratio light increases gibberellin (GA) levels. GA signaling in conifer seedlings requires FR to promote shoot elongation and reduce the inhibition of shoot elongation induced by paclobutrazol (PAC), yet the effects of far-red light in inducing shoot elongation in the presence or absence of PAC is poorly understood. In this study, transcriptomic and proteomic analyses was used to examine the molecular mechanism of FR regulation of shoot elongation in Chinese pine (Pinus tabuliformis Carr.) seedlings in the presence of PAC. Four treatments were compared: white light + water (WW), FR + water (RW), white light + PAC (WP), and FR + PAC (RP), and 1436 differentially expressed genes (DEGs) and 450 differentially expressed proteins (DEPs) were identified in RW_WW (RW contrast WW), and 1862 DEGs and 481 DEPs in RP_WP (RP contrast WP). Metabolic and signal transduction pathway analyses of DEGs and DEPs in RW_WW and RP_WP, indicated that the former required more energy than the latter. Moreover, gibberellic acid, auxin, and brassinolide are equally important in RW_WW and RP_WP for shoot elongation, except for the ethylene pathway. Amino acid metabolism and cell wall organization were significantly enriched in RW_WW and RP_WP, respectively. In summary, RW_WW and RP_WP had different effects in secondary metabolism, energy metabolism, amino acid metabolism, cell wall organization, and hormone response. These results provide an important theoretical and reference basis for studying the regulatory effect of low R/FR and PAC in conifer shoot elongation.

Effects of Seed Soaking with Paclobutrazol on Early Tillering and Endogenous Hormone Contents of Sugarcane Seedlings

[ Objective] The paper was to explore the effect of seed soaking with paclobutrazol （ PP333 ） on early tillering and endogenous hormone content of sugarcane seedlings. [ Method ] With the sugarcane variety ROC22 as the experimental material, seeds were soaked in different concentrations of PP333- The number and growth of tiller were investigated, and the contents of endogenous hormones IAA, CTK, ABA and GA3 at two-leaf, four-loaf and six-leaf stages of sugarcane seedlings were measured, to study the effects of seed soaking with PP333 on early filleting and endogenous hormone contents of sugarcane seedlings. [Result] Seed soaking with PP333 could effectively improve and advance filleting occurrence of sugarcane seedlings. The suitable PP333 concentration for sugarcane fiUeting occurrence, growth and development was 50 mg/L. Seed soaking with PP333 significantly increased the CTK and ABA contents in leaves of sugarcane seedlings, and decreased IAA and GA3 contents. [ Conclusion]The paper will provide a theoretical basis for application of PP333 in sugarcane production.

Effects of exogenous paclobutrazol and sampling time on the efficiency of in vitro embryo rescue in the breeding of new seedless grape varieties

Embryo rescue technology plays an important role in seedless grape breeding.However,the efficiency of embryo rescue,including the embryo formation,germination,and seedling rates,is closely related to the parental genotypes,degree of abortion,growth medium,and plant growth regulators.In this study,we investigated the effects of different concentrations of paclobutrazol(PAC),a plant growth regulator,and embryo collection times on the embryo formation,germination,and seedling rates for different hybrid combinations of grape breeding varieties used for their aroma and cold-resistance traits.The results showed that the different PAC concentrations had varying impacts on the development of ovules and embryos from the different grape varieties.The embryo formation rates of the‘Sultanina Rose’בBeibinghong’and‘Kunxiang Seedless’בTaishan-2’crosses were the highest under the 5.1μmol L^(-1)PAC treatment.The 1.0μmol L^(-1)PAC treatment was optimal for the germination and seedling development of the‘Sultanina Rose’בBeibinghong’embryos,whereas the 0.2μmol L^(-1)PAC treatment induced the highest germination rate for the‘Sultanina Rose’בKunxiang Seedless’cross.The optimal sampling times for each cross varied as 39 d after pollination(DAP)for the‘Flame Seedless’בMuscat Hamburg’cross,46 DAP for the‘Kunxiang Seedless’בBeibinghong’cross,and 41 DAP for the‘Ruby Seedless’בBeibinghong’and‘Fantasy Seedless’בShuangyou’crosses.Moreover,the medium modified with 0.5 g L^(-1)of indole-3-butyric acid allowed the malformed seedlings to develop into plantlets and achieve larger progenies.This study provides a useful basis for further studies into grape embryo rescue and could improve breeding efforts for new seedless grape varieties.

Effects of autoclaving on the physiological action of paclobutrazol

Besides being employed as an efficient plant growth retardant for field, garden and potted plants, paclobutrazol (PBZ) is also used in laboratory experiments, mainly in aseptic cultures, both in autoclaved and non-autoclaved form. Therefore it is not known if autoclaving can partial or completely inactivates the product, thus decreasing its efficacy. Thus a simple experiment was carried out to assess to what extent the autoclaving process can affect some growth components and dry mass accumulation and partition in sunflower seedlings, by employing the techniques of plant Growth Analysis. Autoclaving did not modify either qualitative or quantitatively any of the plant responses to PBZ as well their reversions by gibberellic acid.

外施多效唑诱导水稻对稻飞虱的抗性

【目的】利用化学激发子提高植物抗虫性从而抑制害虫,是目前正在开发的一种新型的害虫绿色防治技术。本研究旨在解析一种化学激发子——多效唑(paclobutrazol,PBZ)提高水稻Oryza savita对稻飞虱抗性的机理,以期为其在害虫防控中的应用打下基础。【方法】用不同浓度PBZ以根吸的方法处理秀水110品种水稻24 h后接入褐飞虱Nilaparvata lugens和白背飞虱Sogatella furcifera初孵若虫,测定接虫后不同时间若虫存活率;用含有5和10 mg/L PBZ或者防御化合物[咖啡酰腐胺、刺苞菊苷和樱桃苷(1和10 mg/L)及芥子酰胍丁胺(0.1和1 mg/L)]的稻飞虱人工饲料饲喂以及用5和20 mg/L PBZ溶液喷施褐飞虱若虫后,测定褐飞虱若虫存活率;5 mg/L PBZ根吸处理水稻、褐飞虱若虫为害和5 mg/L PBZ根吸处理水稻再接褐飞虱若虫后,测定水稻体内水杨酸(salicylic acid,SA)、过氧化氢(hydrogen peroxide,H_(2)O_(2))和乙烯(ethylene,ET)以及防御化合物芥子酰胍丁胺、咖啡酰腐胺、刺苞菊苷和樱桃苷的含量。【结果】与对照(根吸不含PBZ的营养液的水稻)相比,5 mg/L PBZ根吸处理水稻,接虫后3 d时褐飞虱若虫存活率降低33.3%;当PBZ浓度达到20 mg/L时,接虫后4 d时褐飞虱若虫全部死亡,但PBZ本身对褐飞虱若虫没有直接的毒杀作用。与对照组相比,5 mg/L PBZ根吸处理24 h后不接褐飞虱为害放置24 h时水稻植株体内SA含量显著上升,5 mg/L PBZ根吸处理水稻24 h再接褐飞虱若虫为害72 h时H_(2)O_(2)含量显著上升,5 mg/L PBZ根吸处理24 h后不接褐飞虱为害放置48-96 h、褐飞虱为害24-72 h及5 mg/L PBZ根吸处理水稻24 h再接褐飞虱若虫为害48-96 h ET释放量均显著下降,5 mg/L PBZ根吸处理诱导了水稻植株中咖啡酰腐胺和芥子酰胍丁胺2种酚胺类化合物以及刺苞菊苷和樱桃苷2种黄酮类化合物含量的显著上升。在褐飞虱人工饲料中添加1或10 mg/L的咖啡酰腐胺、芥子酰胍丁胺、刺苞菊苷或樱桃苷,可有效降低褐飞虱若虫存活率。【结论】PBZ是一种有效的化学激发子,可以通过激活水稻的SA和H_(2)O_(2)通路、抑制ET通路,诱导水稻相关防御化合物的合成,提高水稻对褐飞虱的抗性。

氮肥运筹与化学调控对双季稻产量及其抗倒伏特性的影响

以早稻品种陆两优996、株两优819及晚稻品种H优518、盛泰优018为材料,于2020年开展大田试验,设计3种氮肥运筹方式N1、N2、N3(分蘖肥、穗肥、粒肥用量比分别为7∶2∶1、6∶3∶1、5∶4∶1)与2种化学调控剂多效唑(C1)、壳寡糖(C2)双因素试验,研究氮肥运筹方式和化学调控对水稻产量及抗倒伏能力的影响。结果表明:氮肥运筹和化学调控对水稻产量影响显著,早、晚稻各品种产量均以N2C2处理的最高,主要通过提高植株有效穗数而增产;与N1相比,N2和N3降低了茎秆高度、节间长度和重心高度,增加了茎粗、茎壁厚度和节间充实度,茎秆抗倒伏能力增强,且N2优于N3处理;与对照处理(C3,喷施清水)相比,C1和C2均降低了水稻茎秆高度、重心高度和节间长度,增加了茎粗、茎壁厚度和节间充实度,从而提高了水稻抗倒伏能力;从互作效应来看,N2C1、N2C2和N3C1处理的茎粗和茎壁厚度较大,倒3与倒4节节间长度较短,节间充实度和抗折力较高,倒伏指数较低。综合考虑各品种倒伏指数和产量性状,N2C2处理,即分蘖肥、穗肥、粒肥施用比例为6∶3∶1条件下,于拔节初期喷施壳寡糖,可在提高双季稻抗倒伏能力的同时获得最高产量。

Chlorocholine chloride and paclobutrazol treatments promote carbohydrate accumulation in bulbs of Lilium Oriental hybrids 'Sorbonne'

The present study was to test the hypothesis that the plant growth retardants chlorocholine chloride(CCC) and paclobutrazol(PBZ)could improve the carbohydrate accumulation in lily bulbs by enhancing photosynthetic capacity and changing endogenous hormones.Plants of Lilium Oriental hybrids'Sorbonne'were treated with a foliar spray of CCC or PBZ(both at 300 mg/L)solution,at six weeks after planting(6 WAP).The morphological parameters,endogenous hormone contents(gibberellic acid(GA),abscisic acid(ABA),and indole-3-acetic acid(IAA)),and carbohydrate contents were measured from 6 to 18 WAP,at 2-week intervals.The results showed that CCC increased the biomass of leaves and stems which might produce more photoassimilates available for transportation and utilization.However,PBZ treatment suppressed vegetative growth and favored photoassimilate transportation into bulbs.A slight delay of bud and anthesis formation was observed in both treated plants.CCC and PBZ treatments substantially enhanced the sucrose contents in leaves probably due to the increase of chlorophyll contents.Treatment with CCC or PBZ decreased GA but increased IAA contents in lily bulbs which might stimulate starch accumulation and formation of new scales.Our experiment suggested that CCC or PBZ treatment is an effective method to promote carbohydrate accumulation in lily bulbs.

植物生长调节剂对香蕉植株的矮化效应

【目的】筛选降低香蕉株高而不影响产量的植物生长调节剂,探究其使用次数对香蕉植株的矮化效应。检测适宜浓度烯效唑对香蕉叶片中几种防御性抗氧化酶活性、可溶性蛋白含量以及钾、钙、镁、磷含量的变化,进一步解析除矮化作用外,烯效唑对香蕉植株生长的正向辅助作用,为在香蕉生产上安全、合理使用植物生长调节剂提供参考。【方法】采用根部淋施法评价烯效唑(XX)、多效唑(DX)、矮壮素(AZ)、甲哌(JP)、复配剂0802和0501等植物生长调节剂对香蕉植株的矮化效应。施用0.3 g/株烯效唑15、20、25 d后,测定香蕉叶片中多酚氧化酶(PPO)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)及可溶性蛋白、钾、钙、镁和磷含量的变化。【结果】根据矮化效果评价标准判断,香蕉植株矮化后可在节间距3~5级别内正常生长。1次矮化处理中,XX1、XX3、DX1、AZ1、JP2、JP4、0501、0802处理香蕉株高降幅在11.67~24.00 cm;2次矮化处理中,JP2、DX1、JP4、0802、AZ1、0501、XX3处理香蕉株高降幅在29.67~39.00 cm,均可正常生长。香蕉株高随着植物生长调节剂浓度、使用次数的增加而降低。XX3、0802、0501处理可促使香蕉提早抽蕾,生育期较对照提前6~19 d,且抽蕾整齐;XX3 2次处理和0802处理的抽蕾率分别可达62.01%、89.32%。随着烯效唑使用浓度的提高,香蕉单株产量呈下降趋势,在1次矮化处理中,XX1、XX3、XX5的单株产量分别为27.26、25.62和23.45 kg,XX3、XX5的单株产量与对照(27.45 kg)相比差异达显著水平,产量稍有降低;0802与0501处理香蕉的单株产量分别为27.37 kg和26.99 kg,与对照差异不显著。2次矮化处理香蕉单株产量结果相似。矮壮素和多效唑在低浓度处理下,可促进香蕉提早抽蕾,但浓度超过0.2 g/株时反而使香蕉抽蕾延迟,且对单株产量影响较大甚至造成减产。烯效唑可提高香蕉叶片中PPO、CAT、PAL活性及可溶性蛋白、钾、钙、镁、和磷含量,具有增强植株抗性作用。【结论】生产上推荐烯效唑、复配剂0802、0501作为香蕉矮化剂,浓度可控制在0.2~0.3 g/株,新植蕉矮化1次。香蕉对多效唑、矮壮素较为敏感,不推荐使用。

定植早期多效唑处理对甘薯块根发育及其蔗糖代谢的影响

施用多效唑(PBZ)可显著提高甘薯块根产量并改善其品质,同时蔗糖分解酶在甘薯块根发育中发挥着重要的调控作用。但目前尚不清楚PBZ调控甘薯块根发育的生理生化机制,更不清楚蔗糖代谢在其中发挥的具体作用。本研究以海南鲜食甘薯主栽品种高系14为材料,研究栽培早期(定植后20~30 d)喷施PBZ对其块根产量、单薯鲜重和单株结薯数,以及不同发育阶段(定植后30、60、90、120 d)块根中的淀粉和可溶性糖(葡萄糖、果糖和蔗糖)含量、蔗糖分解酶活性及其基因家族成员表达水平的影响,以明确PBZ调控甘薯块根发育的蔗糖代谢相关生理生化机制。结果表明:(1)PBZ可通过提高块根单薯鲜重而不是单株结薯数来增加甘薯产量,同时还可以增加块根中的可溶性糖含量和淀粉含量,改善块根品质;但PBZ的增产和改善品质的效果仅发生在处理后的定植早期(定植后30~60 d),在定植后期(定植后90~120 d),PBZ处理对产量和品质无显著影响。(2)PBZ处理显著增加块根的蔗糖合成酶(Sus)、细胞壁转化酶(CWIN)和细胞质转化酶(CIN)活性,但对液泡转化酶(VIN)活性无显著影响。与CWIN和CIN相比,Sus活性上升的时间更早、幅度更大,即PBZ处理下Sus的活性在定植后30 d即显著上升,而CWIN和CIN的活性在定植后60 d才显著上升;在其他时期(特别是定植后期),PBZ处理对Sus、CWIN和CIN活性均无显著影响。(3)对Sus、CWIN和CIN基因表达量的测定表明,在块根中表达的5个Sus基因(IbSus2、IbSus5~7和IbSus9)的表达量在块根发育早期(定植后30 d)均受到PBZ的显著诱导。此外,在块根中表达的7个CIN基因中有3个CIN基因(IbCIN3、IbCIN7和IbCIN8)、在块根中表达的3个CWIN基因中有2个(IbCWIN2和IbCWIN4)基因的表达水平在定植后60 d受到显著诱导。但在其他时期(特别是定植后期),PBZ处理对相关基因家族成员表达水平均无显著影响。结合前人的研究结果,推测PBZ处理下Sus表达和活性增加的时间更早、幅度更大,可以促进淀粉的快速积累和块根的快速膨大,而随后CWIN和CIN表达和活性的上升则可增加块根中的可溶性糖含量,改善甘薯品质,同时为淀粉的合成和块根的膨大提供一定的能量供应。本研究还鉴定出上述3种蔗糖分解酶基因家族中受PBZ诱导表达的特定成员。PBZ对甘薯块根产量、品质、蔗糖分解酶活性及其基因表达水平的影响主要发生在PBZ处理后的短时期内,随着时间的延长,PBZ对上述指标的影响逐渐消失。因此,生产上为了提高甘薯产量,有必要在全生育期进行PBZ处理。上述研究结果可为下一步通过品种选育和栽培措施等手段实现优质、高产甘薯生产提供理论依据。

多效唑对西克刺桐生理特性和花芽分化的影响

【目的】探明多效唑诱导刺桐花芽分化的生理特性,为刺桐花期调控提供理论依据。【方法】以8 a生西克刺桐为试材,测定喷施多效唑后叶片的光合色素、可溶性糖、可溶性蛋白和内源激素等生理指标,分析多效唑对西克刺桐花芽分化的影响。【结果】喷施1.0~3.0 g/L多效唑,能显著提高刺桐叶片的叶绿素和类胡萝卜素含量,促进可溶性糖和可溶性蛋白生成,且各含量均随着多效唑浓度增加呈现先升后降的变化,多效唑浓度为2.0 g/L时均达到最大值;多效唑提高了叶片全碳含量、降低全氮含量,导致碳氮比值提高;多效唑显著降低叶片GA_(3)和IAA含量,提高ZR和ABA含量,造成ZR/IAA、ZR/GA_(3)、ABA/IAA和ABA/GA_(3)比值升高;多效唑显著提高西克刺桐枝条成花率,其中2.0 g/L和3.0 g/L多效唑更有利于西克刺桐的花芽分化。【结论】多效唑有利于促进西克刺桐叶片碳水化合物的生成,提高碳氮比值,调节内源激素平衡,促进西克刺桐的花芽分化,喷施浓度以2.0 g/L效果最好。