Study on the Characteristics of Florescence and Pollen in Lagerstroemia speciosa

[ Objective] To study the characteristics of florescence and pollen in Lagerstroemia speciosa. [ Method ] The process of flower opening and pollen tube germination of Lagerstroemia speciosa was observed and the pollen viability was determined through in vitro germination. [ Result] Sepals of L. speciosa started to diverge at 4：30 am, at 7： 00 am petals flatten up, anther diverged, and the stigma secreted a large number of mucus, it was the best time for artificial pollination. Boric acid and sucrose had a great effect on in vitro pollen germination of L. speciosa, the combination which made highest rate of pollen germination, was sucrose 150 g/L ＋ boric acid 20 mg/L ＋ CaCI2 10 mg/L. Through the fluorescence microscope, it was known that four hours after flowering, a lot of pollen grains germinated on the stigma, six hours after flowering, lots of pollen tubes entered the style and reached to 1/4 length of the style, 12 hours after flowering, pollen tubes concentrated into a beam forward, and reached to 1/2 length of the style, 24 hours after flowering, lots of pollen tubes entered the ovary in a beam and then fertilized and produced seeds. [ Conclusion] The results provide some basis for utilizing L. speciosa to breed.

Research on Plantlet Rooting of Lagerstroemia indica

Tissue culture plantlets of Lagerstroemia indica were used to study the effects of different auxins on in-vitro rooting, and the effects of various media in transplanting of rooted plantlets and ex-vitro rooting. For in-vitro rooting of test-tube plantiets of Lagerstroemia indica, 0.5 mg/L IBA is a suitable growth regulator; in the case of transplanting of rooted plantlets, the medium ratio of peat soil to perlite at 7：3 is better; and as to ex-vitro rooting of Lagerstroemia indica plantlets, the medium ratio of peat soil to perlite at 3：7 is more suitable.

Salt Stress Effect on the Growth and Physiological Characteristics of Three New Varieties of Lagerstroemia indica

The effects of different concentrations of NaCI （0, 0.10%, 0.25%, 0.40%, 0.55%, 0.70%） on the growth and physiological characteristics of three new varieties of Lagerstroemia indica were studied by pot experiment in the plastic greenhouses. The results showed that under different NaCI concentrations, the relative height in- crement and the relative diameter increment of L. indica were restrained obviously; the contents of chlorophyll a, chlorophyll b, carotenoid and GSH decreased with in- crease of NaCI concentration; and the content of MDA increased with increase of NaCI concentration. Through the determination and comparison of physiological in- dexes, and analysis of correlativity, NaCI tolerance of the three new L. indica vari- eties ranked as L. indica ＇Pink Velour＇〉L. indica ＇Dynamite＇〉L. indica ＇Red Rock- et＇. This is consistent with the results of the morphological characteristics after Na- CI stress.

Study on in vitro Culture and Germination of Three Cultivars of Lagerstroemia indica L.

[Objective] The research aimed at investigating the in vitro culture and germination of three cultivars of Lagerstroemia indica L.[Method] The pollen of three L.indica cultivars Hongdiefeiwu,Cuipanjinwei and Zizhuayinwei in full flowering stage was collected as materials to study the effects of in vitro culture on pollen viability and germination.[Result] The optimum medium for L.indica pollen germination was 150 g/L sucrose ＋ 60 mg/L boric acid ＋ 20 mg/L CaCl2＋20 mg/L MgSO4 ＋100 mg/L KNO3,in which,the concentrations of sucrose and boric acid could significantly influence the pollen germination.In addition,the vitality of pollen at long filament differed from that at short filament,wherein,the vitality of pollen at short filament of Zizhuayinwei and Hongdiefeiwu was higher than that at their long filament,while Cuipanjinwei showed the opposite result.Within 2-6 h after pollination self,pollen germinated to form pollen tube,which grew fast firstly and then slowly.[Conclusion] The study provided theoretical reference for breeding new L.indica cultivar.

Phylogeny,molecular evolution,and dating of divergences in Lagerstroemia using plastome sequences

Lagerstroemia L.(Lythraceae)is a widely distributed genus of trees and shrubs native to tropical and subtropical environments from Southeast Asia to Australia,with numerous species highly valued as ornamentals.Although the plastomes of many species in this genus have been sequenced,the rates of functional gene evolution and their effect on phylogenetic analyses have not been thoroughly examined.We compared three plastome sequence matrices to elucidate how differences in these datasets affected phylogenetic analyses.Robust phylogenetic relationships for Lagerstroemia species were reconstructed based on different plastome sequence partitions and multiple phylogenetic methods.Identification of single-nucleotide variants within different genes also provides basic data on the patterns of functional gene evolution in Lagerstroemia and may provide insights into how those mutations affect protein structure and potentially drive divergence via cytonuclear incompatibility.These results as well as analyses of non-synonymous and synonymous mutations,indicate that heterotachic modes of evolution are present in functional plastome genes and should be accounted for in the analyses of molecular evolution.In addition,divergence events within the Lagerstroemia were dated for the first time.Several of the divergence estimates corresponded to well-known Earth history events,such as the reduction in global temperatures at the Eocene/Oligocene boundary.Our analyses conducted in Lagerstroemia here dissects the various patterns in the divergence of Lagerstroemia and may provide a useful guide to help plant breeders,as well as the necessity of using plastomic data and as possible as to combine evidence from morphological characteristics to investigate the complicated interspecies relationship and the evolutionary dynamics of species.

Lagerindicine, a New Pyrrole Alkaloid Isolated from the Flowers of Lagerstroemia indica Linnaeus

A phytochemical investigation of the EtOH extract of the flowers of Lagerstroemia indica L.led to the isolation and char-acterization of a new pyrrole alkaloid,named lagerindicine(1),along with four known compounds(2-5).Their structures were elucidated by the detailed spectroscopic analysis and comparison with literature data,whereas the structure,in par-ticularly,the absolute configuration(AC)of 1,was firmly determined by total synthesis.All the isolates were evaluated for their cytotoxic effects against human colon cancer cell(HCT-116),and compound 3 exhibited weak cytotoxicity with IC50 value of 28.4μM.

A Preliminary Study on Immature Embryo Culture and Plant Regeneration of Lagerstroemia indica

[ Objective ] This study aimed to explore immature embryo culture of Lagerstroemia indica and investigate the appropriate conditions for growth and differentiation. [ Method] Immature embryos of L. indica were employed as the explants for germination induction to establish aseptic lines. Based on that, the effects of different hormone levels and culture conditions on immature embryo culture of L. indica were analyzed. [ Result ] Peeled immature embryos of L. indica were germinated easily, leading to a germination rate of 100%. The optimal initial medium was MS ＋ BA0.5 ＋ NAA0.1 ＋ sucrose 3.0% ＋ agar 0.7% ; the optimal shoot induction medium was MS ＋ BA0.5 ＋ NAA0.1 ＋ sucrose 3.0% ＋ agar 0.7% ＋ coconut milk 10% ; the optimal rooting medium was MS ＋ BA0.5 ＋ IBA0.1 ＋ sucrose 3.0% ＋ agar 0.7% ＋ coconut milk 10%. [ Conclusion] This study provided a technical reference for subsequent optimized breeding of L. indica.

The hypoglycemic effect of Lagerstroemia indica L.and Lagerstroemia indica L.f.alba(Nichols.)Rehd.in vitro and in vivo

Lagerstroemia indica L.has a high medicinal value,its bark,leaves and flowers can be used as medicine.Its flowers are reddish,purple,or white,thereinto,the white one is called L.indica Linn.f.alba(Nichols.)Rehd.,which is a forma of L.indica.In this paper,the hypoglycemic effects of different extracts from flowers of L.indica(LIF)and L.indica L.f.alba(Nichols.)Rehd.(LIAF)were investigated byα-glucosidase inhibitory method in vitro and alloxan-induced diabetic mice model in vivo,respectively.The results in vitro showed that ethyl acetate extracts(EA)of LIF and LIAF(IC_(50)=4.45 and 4.09µg/mL,resepectively)had the highest inhibitory activity ofα-glucosidase,and followed by n-butyl alcohol extracts(BU)(IC_(50)=17.01 and 14.58µg/mL,respectively),and the last was petroleum ether extracts(PE)(IC_(50)=103.29 and 112.47µg/mL,respectively),the activities of all extracts were higher than that of the positive control(acarbose,IC_(50)=1278.83µg/mL).The results in vivo showed that compared with the model control group,each dose group of LIF could significantly(P<0.05,P<0.01 or P<0.001)decrease fasting blood glucose,total cholesterol(TC)level and malondialdehyde(MDA)content in diabetic mice and increase superoxide dismutase(SOD)level(P<0.05)in serum.Partial dose groups of LIF could significantly(P<0.05)decrease postprandial blood glucose,triglyceride(TG)and increase liver glycogen content.Each dose group of LIAF could significantly(P<0.05,P<0.01 or P<0.001)decrease fasting blood glucose,TC level and increase SOD level in serum.Partial dose groups of LIAF could significantly(P<0.05)decrease TG,MDA level and increase liver glycogen content.These results indicate that LIF and LIAF had effective prevention and treatment effects on the development for diabetes.

Synthesis,characterization and application of Lagerstroemia speciosa embedded magnetic nanoparticle for Cr(Ⅵ)adsorption from aqueous solution

Lagerstroemia speciosa bark（LB） embedded magnetic nanoparticles were prepared by co-precipitation of Fe2＋ and Fe3＋ salt solution with ammonia and LB for Cr（Ⅵ） removal from aqueous solution.The native LB,magnetic nanoparticle（MNP）,L.spedosa embedded magnetic nanoparticle（MNPLB） and Cr（Ⅵ） adsorbed MNPLB particles were characterized by SEM-EDX,TEM,BET-surface area,FT-IR,XRD and TGA methods.TEM analysis confirmed nearly spherical shape of MNP with an average diameter of 8.76 nm and the surface modification did not result in the phase change of MNP as established by XRD analysis,while led to the formation of secondary particles of MNPLB with diameter of 18.54 nm.Characterization results revealed covalent binding between the hydroxyl group of MNP and carboxyl group of LB particles and further confirmed its physico-chemical nature favorable for Cr（Ⅵ） adsorption.The Cr（Ⅵ） adsorption on to MNPLB particle as an adsorbent was tested under different contact time,initial Cr（Ⅵ） concentration,adsorbent dose,initial pH,temperature and agitation speed.The results of the equilibrium and kinetics of adsorption were well described by Langmuir isotherm and pseudo-second-order model,respectively.The thermodynamic parameters suggest spontaneous and endothermic nature of Cr（Ⅵ）adsorption onto MNPLB.The maximum adsorption capacity for MNPLB was calculated to be 434.78 mg/g and these particles even after Cr（Ⅵ） adsorption were collected effortlessly from the aqueous solution by a magnet.The desorption of Cr（Ⅵ）-adsorbed MNPLB was found to be more than 93.72%with spent MNPLB depicting eleven successive adsorption-desorption cycles.

广东省重点保护野生植物广东紫薇(Lagerstroemia fordii)的播种育苗

广东紫薇(Lagerstroemia fordii)为中国特有种,广东省首批重点保护野生植物,已经列入《世界自然保护联盟濒危物种红色名录》(IUCN)。该类群当前主要为野生状态,分布于广东、福建中低海拔的山谷、山坡林地,少量零星栽培于植物园,除植物志记载外,国内外对其研究极少,相关资料几乎为空白。在野外资源调查过程中,广东紫薇主要分布在乔木层,林下幼苗很少,与其种子萌发率低,生境土壤基质不适宜有关。本文开展了广东紫薇播种育苗方法的研究,结果表明:浓硫酸及温水浸泡处理可显著提高其种子发芽率,体积比5∶4∶1的泥炭土、粗河沙、蛭石的播种基质和体积比6∶3∶1的泥炭土、塘泥和蛭石的育苗基质可明显提高幼苗的生长速率,改善其生长状况。本研究为该类群大规模人工扩繁,为进一步开展野外回归,园林应用提供了关键的技术参考。

育苗容器对紫叶紫薇容器苗生长、开花及生理的影响

【目的】探讨育苗容器类型和规格对紫叶紫薇容器苗生长、开花及生理的影响,筛选出培育紫叶紫薇容器苗的适宜育苗容器,为高效培育紫薇容器苗提供理论依据。【方法】以紫叶紫薇优良新品种‘丹红紫叶’2年生苗木为研究材料,选用黑色塑料营养杯(C1)、白色无纺布美植袋(C2)、黑色控根容器(C3)3个类型以及16×16(D1)、21×21(D2)、25×25(D3)3种规格(直径×高,cm),组成9种容器组合处理,测定不同处理容器苗生长、开花及生理指标。【结果】(1)不同育苗容器处理对紫叶紫薇容器苗的生长、开花及生理指标均影响显著,同一容器类型苗木的生长、根系、生物量、花期、花径、花序、可溶性蛋白含量、可溶性糖含量、相对叶绿素含量、净光合速率、气孔导度、蒸腾速率等指标均随着育苗容器规格的增大而显著增加。(2)地径生长量、总根长、总根表面积、总根体积、根尖数、地上部干质量、地下部干质量、总干质量、花期均以C3D3处理最大,比最小的C1D1处理分别显著提高817.12%、108.12%、94.60%、75.66%、144.14%、135.67%、228.45%、164.65%、34.48%;苗高生长量、冠幅生长量、叶面积、花序长和宽均以C1D3处理最高,比最低的C1D1处理分别显著提高116.05%、81.39%、114.95%、70.44%和65.79%;相对叶绿素含量、水分利用效率均以C3D3处理最大,可溶性蛋白和可溶性糖含量、净光合速率、气孔导度均以C1D3处理最高;胞间CO_(2)浓度、水分利用效率在各处理之间无显著差异。(3)各处理隶属函数法综合评价得分排序为:C3D3>C1D3>C2D3>C3D2>C2D2>C1D2>C2D1>C3D1>C1D1。【结论】黑色控根容器在地径生长量、根系生长指标、生物量、花期和花径、叶绿素相对含量及净光合速率方面表现最佳;紫叶紫薇2年生苗的最适宜育苗容器是直径25 cm、高25 cm的黑色控根容器。

干旱胁迫对紫叶紫薇容器苗生长及生理的影响

为探究干旱胁迫对紫叶紫薇容器苗的生长及生理影响,以紫叶紫薇优良新品种‘丹红紫叶’2年生容器苗为研究对象,设计了5个干旱胁迫强度处理,测定不同干旱胁迫处理对容器苗生长及生理相关指标的影响。结果表明:干旱胁迫对紫叶紫薇容器苗的生长及生理的影响显著。随着干旱胁迫强度增加,紫叶紫薇容器苗叶片相对含水量、过氧化物酶活性、超氧化物歧化酶活性、可溶性蛋白含量、净光合速率、气孔导度、蒸腾速率总体上呈现降低趋势,重度干旱时这些指标分别比正常供水显著下降了21.45%、40.45%、31.92%、3.30%、81.25%、89.29%、87.17%,极重度干旱时达到最低值。可溶性糖含量、脯氨酸含量、丙二醛含量随着干旱胁迫程度增强而一直上升,重度干旱时分别比正常供水显著增加了122.92%、74.98%、288.34%,极重度干旱时达到最大值。随着干旱胁迫强度加重,过氧化氢酶活性、叶绿素相对含量、水分利用效率呈现先升高后降低的趋势,中度干旱时过氧化氢酶活性最大,叶绿素相对含量和水分利用效率则是轻度干旱最高,极重度干旱时最低。胞间CO_(2)浓度随着干旱胁迫加强而先降后升,正常供水的胞间CO_(2)浓度最高,中度干旱最低。紫叶紫薇容器苗具有抵御中度干旱的能力,当土壤相对含水量下降至30%~35%时应及时给苗木浇水灌溉。

淹水胁迫对紫薇苗生长及生理特性的影响

以紫薇优良新品种‘丹红紫叶’二年生苗为试材,采用套盆淹水方法,设计了5个淹水持续时间处理,研究不同淹水胁迫处理对紫薇苗生长及生理指标的影响,以期为紫薇苗培育及园林应用的水分管理提供参考依据。结果表明:紫薇能承受14 d的淹水,淹水21 d是紫薇忍受淹水胁迫持续时间的极限。随着淹水胁迫时间增长,紫薇苗的叶片相对含水量、过氧化物酶活性、超氧化物歧化酶活性、可溶性蛋白质含量、净光合作用速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、胞间CO_(2)浓度(Ci)均总体呈下降趋势,淹水21 d时分别比对照处理显著下降了24.29%、79.88%、18.66%、3.16%、80.45%、92.51%、93.10%、25.43%,淹水28 d时达到最低值;脯氨酸、丙二醛含量呈上升趋势,淹水21 d时分别比对照显著增加67.34%、360.54%,淹水28 d最大;过氧化氢酶活性呈先升后降的趋势,淹水21 d最大,比对照显著增加252.65%;可溶性糖含量呈先降后升再降的趋势,淹水21 d最大,比对照显著增加19.38%;淹水胁迫期间紫薇苗的叶绿素相对含量变化不明显;水分利用效率(WUE)呈起伏波动走势,对照最低,淹水21 d较高,比对照显著高184.00%。紫薇苗具有一定的耐涝性,淹水胁迫持续时间不宜超过14 d。

不同基质对‘丹红紫叶’紫薇容器苗开花和光合特性的影响

[目的]为探究不同育苗基质对‘丹红紫叶’紫薇容器苗开花及光合特性的影响,筛选出紫薇容器苗培育的适宜育苗基质,为紫薇容器苗高效培育提供理论指导。[方法]以‘丹红紫叶’紫薇2年生容器苗为研究对象,用圃地土、泥炭、珍珠岩、蛭石不同比例配制16种育苗基质处理,以圃地土为对照(CK)基质,测定不同处理对容器苗开花及光合特性的影响。[结果]不同育苗基质对‘丹红紫叶’紫薇容器苗的开花及光合特性影响显著,T11处理的开花指标和光合特性指标综合表现最好,花期、花径、花序长和宽分别比CK增加了23d、22.63%、26.40%和30.20%,叶绿素相对含量、净光合速率、蒸腾速率、气孔导度、水分利用效率分别比CK显著提高了8.88%、413.58%、115.20%、100.00%、138.46%,T11处理的胞间CO 2浓度最低,比CK显著降低29.27%。开花指标与光合特性指标的相关性分析表明,花序与净光合速率、水分利用效率显著正相关,与胞间CO_(2)浓度显著负相关。主成分分析的综合得分最高为T11处理,最低为CK,T11处理基质配方有利于促进‘丹红紫叶’紫薇容器苗开花,提高光合效率。[结论]圃地土30%+泥炭50%+蛭石10%+珍珠岩10%的基质是‘丹红紫叶’紫薇2年生容器苗培育的最适宜基质。

紫薇响应盐胁迫和碱胁迫的代谢组分析

为探究‘红叶’紫薇(Lagerstroemia indica ‘Pink Velour’)对盐胁迫和碱胁迫的代谢响应机制,对‘红叶’紫薇1年生无性扦插苗分别进行盐胁迫(NaCl,pH=7.02)和碱胁迫(NaHCO_(3)和Na_(2)CO_(3)的Na^(+)摩尔比为2:1,pH=9.52)处理,采用液相色谱质谱(LC-MS)分析叶片代谢组学变化,并比较2个处理组与对照(CK)之间的代谢差异。结果表明:与CK相比,盐处理组共筛选出156个差异代谢物,碱处理组共筛选出176个差异代谢物,2个对比组共有23个差异代谢物,其余均为特有差异代谢物。KEGG富集分析表明,次生代谢产物生物合成、氨基酸代谢、糖类代谢、脂肪酸代谢和植物激素合成是响应盐胁迫和碱胁迫的主要代谢通路;甘氨酸、丝氨酸和苏氨酸合成代谢、ABC转运蛋白和维生素B_(6)合成代谢是盐胁迫组的特有代谢通路;缬氨酸、亮氨酸、异亮氨酸、精氨酸和脯氨酸生物合成代谢、叶酸合成代谢,以及戊糖和葡萄糖醛酸相互转化和抗坏血酸合成代谢是碱胁迫组的特有代谢通路。这些差异代谢物变化和代谢通路富集可能是紫薇响应盐胁迫和碱胁迫的主要机制。

3个彩叶紫薇品种的扦插繁殖对比试验

为获得紫薇硬枝扦插的最佳繁殖方法,以美国红叶紫薇、“红云”紫薇、“农紫1号”紫薇3个品种为试验材料,分别以不同品种、不同激素种类、不同激素浓度为试验因素,对紫薇的硬枝扦插繁殖进行了对比试验。结果表明:春季3月下旬至4月上旬进行硬枝扦插,插前将插穗基部在NAA、IBA以及(NAA+IBA)1500 mg/L的溶液中浸泡2 h后进行扦插,30 d后调查发现,3个品种以“农紫1号”紫薇的生根效果最好,生根率最高达92.4%。单独使用NAA、IBA溶液或使用NAA与IBA的混合溶液对扦插效果的影响不显著,对于扦插效果的影响主要体现在浸泡溶液的浓度上,使用1500 mg/L效果最好,与其他水平间均存在显著差异,该浓度下紫薇的平均生根率为91.00%,平均根长为3.00 cm,平均根量为7.93条。

不同施肥配比对紫薇叶片内源激素含量的影响

以‘紫精灵’紫薇为研究对象,开展不同施肥配比对紫薇叶片内源激素含量影响的试验研究,旨在为探明施肥促进紫薇生长的机制提供理论依据。以‘紫精灵’紫薇2年生苗为研究材料,采用氮、磷、钾3因素4水平的“3414”施肥试验设计,测定不同处理的叶片内源激素含量。结果表明:氮、磷、钾施肥显著提高了紫薇叶片IAA、GA_(3)、ZR含量和(IAA+GA_(3)+ZR)含量/ABA含量比值,比不施肥处理T1(N 0P 0K 0)分别提高了26.35%~146.51%、10.82%~104.74%、27.26%~247.80%、72.03%~456.73%,T6(N 2P_(2)K_(2))处理的IAA和ZR含量最高,T3(N_(1)P_(2)K_(2))处理的GA_(3)含量和(IAA+GA_(3)+ZR)含量/ABA含量比值最大;施肥显著降低了叶片ABA含量,比不施肥处理T1降低了18.36%~57.17%,T3处理的ABA含量最低。随着氮、磷、钾肥施用量的增加,紫薇叶片IAA、GA_(3)、ZR含量呈现先升后降的趋势,ABA含量呈现先降后升的趋势。氮肥对紫薇叶片IAA、GA_(3)、ZR含量的影响最大,磷肥对叶片ABA含量、(IAA+GA_(3)+ZR)含量/ABA含量比值的影响最大。氮、磷、钾施肥可影响叶片内源激素的含量而调控紫薇的生长。

紫薇种子无菌萌发与快繁技术研究

以花瓣深粉红色的紫薇品种“彩霞满天”(Lagerstroemia indica‘Caixia Mantian’)的自然结实种子为试验材料,建立种子无菌萌发体系,以试管苗探索基本培养基类型、植物生长调节剂种类及浓度对不定芽增殖和根系诱导的影响,筛选出无菌苗“一步法”增殖、生根培养基。结果表明:紫薇种子无菌萌发最佳消毒方案为先用75%乙醇消毒2 min后,用2.5%NaClO消毒5 min;相同灭菌方案下接种于WPM培养基的紫薇较接种于MS的紫薇褐化率总体偏少,且较接种于1/2MS和MS中无菌萌发苗的茎粗壮且叶色浓绿;筛选出紫薇“一步法”增殖、生根最佳培养基为WPM+6-BA 1.5 mg/L+IBA 0.05 mg/L,试管苗叶色浓绿,增殖系数达到3.09,平均芽长为5.21 cm,平均生根率达75.00%,单株平均生根数为2.78。

配方施肥对紫薇花序着花数和花期的影响

为探究紫薇花序着花数和花期对氮、磷、钾配方施肥的响应,获得氮、磷、钾优化的施肥量,以紫薇优良新品种“紫精灵”为研究对象,采用氮、磷、钾“3414”施肥设计进行田间施肥试验,测定不同处理的花序着花数和花期,拟合花序着花数的肥料效应模型,采用频次分析法获得优化施肥量。结果表明:氮、磷、钾配方施肥显著提高了紫薇花序着花数,能提早始花期和盛花期、推迟末花期;施肥对紫薇花序着花数、花期、始花期、盛花期、末花期的单因子影响效应均是N>K>P,交互作用影响效应都是NK>NP>PK;氮、磷、钾对花序着花数的单因素效应为正,氮与磷交互效应为正,氮与钾、磷与钾的交互效应都是负;花序着花数最大的施肥量为氮肥(N)19.50g·株^(-1)、磷肥(P_(2)O_(5))13.82g·株^(-1)、钾肥(K_(2)O)3.66g·株^(-1),此时花序着花数为117.94朵;用频次分析法获得的优化施肥量为氮肥(N)10.95~17.37g·株^(-1)、磷肥(P_(2)O_(5))5.89~9.37g·株^(-1)、钾肥(K_(2)O)7.01~10.25g·株^(-1),预期花序着花数平均值为126.52朵。

The anthocyanin formation of purple leaf is associated with the activation of LfiHY5 and LfiMYB75 in crape myrtle

Purple-leafed plants not only have a higher resistance to biotic and abiotic stresses,but also have higher ornamental value.Anthocyanins are vital for leaf color formation,growth and development of purple leaves.However,the molecular mechanism underlying purple leaf formation in Lagerstroemia indica remains unclear.Metabolomic and transcriptomic analysis of purple-leafed cultivar‘Ebony Embers’and greenleafed cultivar‘Arapahoe’showed that the high expression of anthocyanin structure genes induced hyperaccumulation of cyanidin and pelargonidin derivatives,making the leaves purple.LfiHY5,LfiMYB75 and LfibHLH1 were identified using correlation analysis and weighted gene co-expression network analysis.In‘Arapahoe’‘Ebony Embers’population,LfiHY5 and LfiMYB75 showed significant positive correlation with leaf anthocyanin content.Transient expression of LfiMYB75 and LfiHY5 in tobacco and purple-leafed crape myrtle indicated that the two genes activated anthocyanin synthesis.Yeast two-hybrid analysis showed that LfiMYB75 and LfibHLH1 could form a complex that enhanced anthocyanin synthesis.Yeast monohybrid and dual-luciferase assays confirmed that LfiHY5 activated the expression of LfiMYB75,to activate the transcription of anthocyanin structural genes LfiCHS and LfiANS.Moreover,there were three alleles of LfiHY5 in crape myrtle,and the different sequences had different activation effects on LfiMYB75.In conclusion,the results showed that LfiHY5 led to upregulate the transcription of LfiMYB75,and LfiMYB75 formed a complex with LfibHLH1,which increased the transcription level of LfiCHS and LfiANS to affect anthocyanin synthesis in crape myrtle.