Phytochemical screening and free radical scavenging activity of Citrullus colocynthis seeds extracts

Objective:To study the phytochemical screening of different extracts from Citrullus colocynthis(C.colocynthis)seeds extracts and to assess their antioxidant activity on the DPPH free radical scavenging.Methods:Phytochemical screening,total content of polyphenols and flavonoids of C.colocynthis seeds extracts,including a crude aqueous extract(E1),a defatted aqueous extract(E2),a hydromethanolic extract(HM),an ethyl acetate extract(EA)and a n-butanol extract(n-B)was carried out according to the standard methods and to assess their corresponding effect on the antioxidant activity of this plant.Results:None of these extracts contained detectable amount of alkaloid,quinone,antraquinone,or reducing sugar.Catechic tannins and flavonoids were abundant in E1,MM and EA,whilst terpenoids were abundantly present in E1 and n-B but only weekly in HM.Coumarins were found in E2,EA and n-B.Polyphenols,expressed as gallic acid equivalent,amounted,per 100 g plant matter,to 329,1002 and 150 mg in EA,HM an E1 respectively.Flavonoids,expressed as catechin equivalent,amounted.per 100 g plant matter to 620,241 and 94 mg in EA,HM and E1 respectively.Comparable values were found in n-B and E1,with lower values in E2.Quercetin,myricetin and gallic acid were found in the EA and HM extracts by thin layer chromatography,The antioxidative effect of these extracts yielded,when tested at a concentration of 2000μg/mL in a 1,1-diphenyl-2-picrylhydrazyl assay,a reducing percentage of 88.8%with EA,74.5%with HM and 66.2%with E1,and corresponding IC_(50)of 350,580and 500μg/mL as compared to 1.1μg/mL for ascorbic acid.Conclusions:These qualitative and quantitative analytical data document the presence in C.colocynthis extracts of such chemical compounds as flavonoids responsible for the antioxidant activity,as well as other biological activities of this plant.

Enhancing the Salt Tolerance Potential of Watermelon (<i>Citrullus lanatus</i>) by Exogenous Application of Salicylic Acid

Salicylic acid (SA) is a vital plant growth regulator providing promising role in plant development and adopts defense mechanism to abiotic stresses. Salinity is the most limiting abiotic factor for plant development and growth changes in watermelon by producing reactive oxygen species and ultimately oxidative stress. The present study was aimed to investigate the mechanism involved in salt stress alleviation in watermelon (Citrullus lanatus Thanb. Mavs.) through the foliar application of salicylic acid. Watermelon cv. Charleston Gray was grown under moderate saline regime of 3 ds·m-1 NaCl and sprayed with salicylic acid with four level (0.5, 1.0, 2.5 and 5.0 mmol/L) compared along with control. SA @ 5.0 mmol/L was found to be very effective in mitigation of salt stress. SA was found to be very effective in alleviation of salinity stress by produced antioxidants and acted as osmo-regulator.

Nutritive Values and Antioxidant Activity of <i>Citrullus lanatus</i>Fruit Extract

Citrullus lanatus (Watermelon) is a fruit cultivated and consumed in Africa for its essential nutrients which are very beneficial to the human body. The present study was designed to evaluate the nutritive contents, free radical scavenging activities and phytochemical components of C. lanatus fruit. The extract of the fruit was subjected to in vitro antioxidant assessment using 1,1-di-phenylpicryl-hydrazyl radical (DPPH) and hydrogen peroxide radical scavenging assays. The proximate and phytochemical analyses were conducted using standard procedures. The results of this study showed that C. lanatus fruit had very high moisture content and its crude protein, crude fat, crude fibre and ash content were all in traceable amounts. The sugar content was considerably high in comparison with other nutritive contents. Lycopene and β-carotene contents of C. lanatus fruit were estimated to be 4537.83 and 308.71 μg/100g respectively. The gross energy evaluation showed a value of 0.335 Kcal/g. The fruit extract exhibited significant (p 50 of 0.10 mg/ml) and hydrogen peroxide radicals scavenging activity (IC50 of 0.62 mg/ml) in comparison with the positive control butylated hydroxytoluene (BTH). This study therefore recommends that C. lanatus fruit could be an excellent source of antioxidants which may prevent diseases whose pathogenesis involves oxidative stress.

Hepatoprotection: A Hallmark of <i>Citrullus colocynthis</i>L. against Paracetamol Induced Hepatotoxicity in Swiss Albino Rats

Objective: To demonstrate the in-vivo hepatoprotective effect of the ethanolic extracts of Citrullus colocynthis (Linn.) against paracetamol induced hepatotoxicity in albino rats. Animal Model: Swiss Albino rats of either sex were used, divided into six groups with six in each group. Group 1-Normal control: The animals were maintained under normal control, which were given distilled water only. Group 2-Induction of hepatotoxicity: The animals received paracetamol 500 mg/kg b.w. (p.o) every 72 h for 10 Days. Groups 3 to 5: Animals received ethanolic extract of Citrullus colocynthis L. at 50, 100 & 200 mg/kg bw/day for 7 days (p.o). Group 6: The animals were treated with Silymarin (100 mg/kg p.o) which served as standard. Groups 3 to 6 were intoxicated with paracetamol (500 mg/kg bw) 1 h before the administration of extract or Silymarin for 10 days. Histopathological findings, different hepatic biochemical parameters viz. AST, ALT, ALP, Total bilirubin, Total cholesterol, Triglycerides, & the body weight before & after treatment were evaluated to investigate the hepatoprotective activity. Results: Paracetamol induced a significant rise in AST, ALT, ALP, Total Bilirubin, Total Cholesterol, Triglycerides. Administration of 200 mg/kg bw of ethanolic extract of Citrullus colocynthis L. effectively reduced these pathological damages caused by paracetamol intoxication. In addition to serum parameters treatment of 200 mg/kg bw of ethanolic extract of Citrulus colocynthis L. also promotes the body weight in albino rats as shown in Figure 6 respectively. Histopathological changes of the liver samples were compared with the normal control as shown in Figures 2-5 respectively. Conclusion: From our results we may infer that the mode of action of 90% ethanolic extract of Citrullus colocynthis L. (200 mg/kg bw) in affording the in-vivo hepatoprotective activity against paracetamol may be due to the cell membrane stabilization, hepatic cell regeneration & normalizing the serum parameters.

In vitro Screening of Fusarium Wilt-resistant Germplasm Resources of Red Edible Seed Watermelon( Citrullus lanatus ssp. vulgaris var. megalaspermus Lin et Chao)

[ Objective] This study aimed to establish an appropriate technology system for in vitro screening of Fuzarium wilt-resistant germplasm resources of red edible seed watermelon and obtain variants resistant to fusaric acid, thus providing resistant materials for breeding Fusarium wilt-resistant red edible seed watermel- on. [ Method] Using Zhongxin No. 1 red edible seed watermelon advemitious buds as screening materials and fusaric acid （FA） as a stress agent, in vitro screen- ing of Fusarium wilt-resistant red edible seed watermelon clonal variants and identification of Fusarium wilt-resistance of the germplasm resources of red edible seed watermelon were performed. [ Result] The results showed that the appropriate FA for in vitro screening of Fusarium wilt-resistant red edible seed watermelon vari- ants was 15 mg/L. In vitro screening system for Fusarium wilt-resistant red edible seed watermelon variants was established preliminarily and FA-resistant regenera- ted plants were obtained. Among the 36 germplasm resources of red edible seed watermelon, there were 2 highly resistant materials, 6 moderately resistant materi- als, 11 slightly resistant materials and 17 highly susceptible materials. [ Conclusion] This study confirmed preliminarily that in vitro screening method is effective for obtaining resistant materials of red edible seed watermelon.

药西瓜(Citrullus colocynthis)UDP-糖基转移酶基因表达分析

以药西瓜为试材,采用连接转化、双酶切等方法,在前期克隆得到的2个药西瓜UDP-糖基转移酶基因UDP-E1、UDP-E2的基础上,将目的基因UDP-E1、UDP-E2与pET28a连接,构建重组质粒pET28a-UDP-E1和pET28a-UDP-E2,将重组质粒转化至E.coli BL21中,经过不同浓度的IPTG诱导,期望出现目的蛋白条带,且上清中的目的蛋白条带较沉淀与对照组明显。结果表明:成功构建原核表达重组质粒,IPTG浓度为1.0 mmol·L-1时,UDP-E1的融合蛋白分子量约为49 kDa,IPTG浓度为0.8 mmol·L-1时,UDP-E2的融合蛋白分子量约为32 kDa,目的蛋白在大肠杆菌BL21中得到了高效表达。

Phytochemical investigation, antioxidant and wound healing activities of Citrullus colocynthis (bitter apple)

Objective: To undertake metabolite profiling of various plant parts of Citrullus colocynthis, and assess antioxidant and wound healing activities of fractions for therapeutical applications. Methods: Extracts from leaves, stem, root, fruit pulp and seeds were analyzed using gas chromatography-mass spectrometry and high performance liquid chromatography. Variation in antioxidant potential was assayed by 1,1-diphenyl-2-picrylhydrazyl(DPPH) free radical scavenging assay. The extract with highest antioxidant potential was subjected on in-vivo wound healing activity using excision wound model. Results: Metabolite profiling of Citrullus colocynthis identified 70 chemically diverse metabolites from different plant parts by using a combination of GC-MS and HPLC. Concentration of colocynthin, a principal active secondary metabolite, ranged from 3.15 mg/g dry weight to 242.00 mg/g dry weight, the lowest being in leaves and highest in fruit pulp. DPPH radical scavenging activity of free radical(IC50) ranged from 196.44 μg/mL in fruit pulp to 413.33 μg/mL in leaves tissues. Significant wound contraction and increase in hydroxyproline content of granulation tissue were observed with ointment formulated from methanolic extract of fruit pulp. Conclusions: The study indicates that the methanol extract of Citrullus colocynthis fruit pulp when applied topically may promote wound contraction in rat model attributable to the accumulation of colocynthin. The high quantity of colocynthin(242.00 mg/g dry weight) and substantial concentration of 2,4-di-tert butyl phenol(3.2%), squalene(4.2%) and δ-tocopherol(2.5%) make this plant to provide new opportunities for development of medicinal, nutraceutical and dietary supplements with optimized functionality.

Characterization of Water Melon (<i>Citrullus lanatus</i>) Genotypes under High Salinity Regime

For horticultural crops and especially for vegetables, salinity is dilemma. It is the most limiting factor for plant growth and development by producing reactive oxygen species and ultimately oxidative stress. In the present study, the screening of watermelon (Citrullus lanatus Thanb. Mavs.) Cultivars was observed for salt tolerance. Four salinity levels (1.5, 3, 4.5, and 6 dS·m-1 NaCl) and six cultivars (Crimson, Charleston Gray, Anarkali, Chairman, Sugar Baby and Champion) tested for screening. It was observed that all morphological attributes and ionic contents were severely affected. But it was revealed by statistical analysis that Charleston Gray was affected least while Champion was most salt sensitive cultivar due to oxidative stress and ionic toxicity. It is concluded that different genotypes under consideration vary in their ability to tolerate salt stress.

Colocynth (<i>Citrullus colocynthis</i>) Flesh Extract Suppresses Adipogenesis by Down-Regulating Adipogenic Transcription Factors and Their Target Genes in 3T3-L1 Preadipocytes

Citrullus colocynthis, a member of the Cucurbitaceae family, is widely distributed in North Africa. The fruits are recognized for their wide range of medicinal uses and promising pharmaceutical potential. The present study aimed to investigate the anti-obesity effect of the ethanol extract of colocynth flesh (FCEE) in 3T3-L1 cells following treatment at different doses. The viability of 3T3-L1 preadipocytes was analyzed via MTT assay and triglycerides were stained with Oil red O to assess lipid accumulation. Additionally, adipogenesis-related gene expression was quantified via qRT-PCR. FCEE (0 - 150 μg/mL) dose-dependently suppressed intracellular triglyceride accumulation during the adipogenesis by 23% and 66% at 100 and 150 μg/mL, respectively, but did not affect cell viability. Analysis of the time-dependence of the effect of FCEE demonstrated that the greatest anti-adipogenic activity was observed during the early stages of differentiation. FCEE also decreased GPDH activity in a dose-dependent manner, with 98% decrease observed at 150 μg/mL. In addition, at same range of FCEE concentrations, the main transcription factors, including CCAAT/enhancer binding protein α (C/EBPα), peroxisome proliferator activated receptor γ (PPARγ), and sterol regulatory element-binding protein 1c (SREBP-1c), were downregulated by 90%, 89%, and 89%, respectively at 150 μg/mL. As these are the master regulators of adipogenesis. The inhibition of their downstream target genes was also observed. Colocynth may be useful in the treatment of obesity owing to its powerful effects on fat, which result in changes to adipocyte differentiation and fat mobilization.

Preparation and Characterization of Alkyd Resins Based on Citrullus colocynthis Seed Oil

In this study,different samples of alkyd resins based on Citrullus colocynthis seed oil(CCSO)—which has a high content of linoleic acid—were prepared as a renewable raw material.Short(I),medium(II),and long(III)alkyd resins were synthesized using oil,glycerol,and phthalic anhydride(PA)in different proportions.Prunus mahaleb seed oil(PMSO),which contains conjugated linolenic acid,was blended with CCSO in different proportions to examine the effect of PMSO on the film properties of alkyd resins(IV and V).All synthesized resins were characterized by FTIR and 1H NMR spectroscopic analysis.These resins were also cured by an epoxy resin and their film properties(pencil hardness,adhesion,gloss,and chemical resistance)were determined.Analysis of these alkyds reveals that CCSO can be used as a new potential raw material for coating applications.

Synergistic Hepatoprotective Effect of Feronia fimonia L,, Citrullus colocynthis L,, and Tribulus terrestris L, against Paracetamol Induced Hepatotoxicity in Swiss Albino Rats

Paracetamol toxicity induced a significant rise in AST （aspartate transaminase）, ALT （alanine transaminase）, ALP （alkhaline phisphatase）, total bilirubin, total cholesterol, Triglycerides. Administration of 150 mg/kg b.w of synergistic ethanolic extracts of Feronia limonia L., Citrullus colocynthis L., and Tribulus terrestris L. effectively reduced these pathological damages caused by paracetamol intoxication. In addition to serum parameters treatment of 150 rng/kg b.w of synergistic ethanolic extract of Feronia limonia L., Citrullus colocynthis L. and Tribulus terrestris L. also promote the body weight in albino rats. Histopathological changes of the liver samples were compared with the normal control. From our results, we may infer that the mode of action of synergistic 90% ethanolic extracts of Feronia limonia L., Citrullus colocynthis L., and Tribulus terrestris L. （150 mg/kg b.w） in affording the in vivo hepatoprotective activity against paracetamol may be due to the cell membrane stabilization, hepatic cell regeneration and activation of antioxidative enzymes such as glutathione reductase, glutathione peroxidase, superoxide dismutase and catalase.

Lycopen’s Stability in Watermelon Juice (<i>Citrullus lanatus</i>) Regarding to Technological Routes

Highly prized by consumers, watermelon is rich in water, but also in micronutrients including lycopene, pigment responsible for the red color. It is also a powerful antioxidant which has many virtues including the prevention and treatment of certain diseases. The transformation into nectar of watermelons combined with treatment could cause several modifications including the alteration of coloring. It is in this context that this study focuses on the variation of the lycopene content in nectars. Thus, nectars of 12°Brix and 15°Brix were prepared from three varieties of watermelon (Sugar Baby, Crimson Sweet and Charleston Gray). To study the stability, two pasteurization scales (85°C/15min and 95°C/15min) and one sterilization scale (105°C/15min) were applied to the different nectars produced. The results obtained showed that the Sugar Baby variety is richer in lycopene (24.39 mg·kg-1) with a higher pH (5.80). In addition, the study showed, for the Sugar Baby variety, an increase of lycopene with the addition of sugar and the heat treatment (a maximum of 42.83 mg·kg-1 for SbF12T105). On the other hand, for the Crimson Sweet and Charleston varieties, the highest rate of lycopene, except the heat-treated ones, are those formulated at 12°B (10.46 mg·kg-1 for CrF12T105 and 18.40 mg·kg-1 for ChF12T105). Without any health consequences, the formulation combined with heat treatment would preserve the lycopene content of watermelon nectars.

凉州区设施西瓜周年长季节栽培管理技术

随着设施农业的快速发展和人们生活水平的提高,越来越多的消费者对于新鲜、高档、绿色水果的需求量不断上升。为了进一步提高西瓜的品质,为设施西瓜种植产业的健康发展提供指导和依据,以武威市凉州区设施西瓜种植为例,从秧苗定植、覆盖地膜、枝蔓管理、授粉管理、病虫害防控到设施环境调控、采收与茬口安排等方面,详细介绍了设施西瓜周年长季节栽培管理农艺措施,以为设施西瓜种植户提供借鉴。

西瓜ClPP2C3克隆及表达分析

【目的】蛋白磷酸酶2C(protein phosphatase 2C,PP2C)是动植物中均存在的一类蛋白磷酸酶,拟探究其在西瓜果实成熟过程中发挥的重要作用。【方法】通过逆转录PCR(reverse transcription-polymerase chain reaction,RT-PCR)从栽培类型西瓜‘97103’中克隆ClPP2C3,并对其进行生物信息学、表达模式和亚细胞定位分析。【结果】西瓜ClPP2C3的cDNA序列长度为1317 bp,编码438个氨基酸,其分子量大小为47.81 kD,蛋白质等电点为5.12。ClPP2C3包含1个PP2C保守结构域,与负调控果实成熟的番茄SlPP2C3、草莓FaABI1具有较高的同源性。西瓜ClPP2C3在细胞核表达。ClPP2C3在含糖量高的栽培品种中表达量显著高于含糖量低的野生品种。栽培品种ClPP2C3的2kb片段长度启动子活性显著高于野生品种,而1kb片段长度启动子活性之间无显著差异。【结论】由1-2kb区间SNP导致的启动子活性差异对不同含糖量品种ClPP2C3表达量存在影响。

噻虫胺种子处理对西瓜生长发育的影响及其残留分析

为明确新烟碱类杀虫剂噻虫胺种子处理对西瓜生长发育和品质的影响,以及在西瓜中的残留状况,本研究以10%噻虫胺种子处理悬浮剂为供试药剂,采用拌种试验,开展噻虫胺对西瓜生长发育的影响及残留分析研究。结果表明,噻虫胺有效成分用量100~250 g/100 kg范围内,对西瓜出苗安全;噻虫胺拌种处理对西瓜苗期的株高、茎粗、叶绿素含量和叶面积有一定的促进作用,随着西瓜的生长促进作用减弱,西瓜出苗后30 d,各处理间差异不显著;噻虫胺各处理西瓜产量均高于空白对照,对西瓜有一定的增产作用;噻虫胺拌种可不同程度地提高西瓜果实中可溶性糖、可溶性固形物含量,提升西瓜的品质;随着西瓜生长发育,叶片内噻虫胺含量逐渐降低,出苗后45 d,叶片内未检测到噻虫胺残留;西瓜收获时果实中未检测到噻虫胺残留,西瓜根部土壤中噻虫胺的残留量在0.0412~0.0975 mg/kg之间。综上所述,噻虫胺100~250 g/100 kg用量范围内处理西瓜种子,对西瓜苗期生长有一定促进作用,并可提高产量,改善西瓜的品质,叶片内噻虫胺含量随植株生长逐渐降低,果实中无残留,本研究为噻虫胺种子处理在西瓜生产实践中合理、安全、高效的应用提供技术支撑。

微量苯酚-硫酸法快速测定西瓜翠衣多糖含量

目的建立微量苯酚-硫酸法对西瓜翠衣多糖进行快速测定的方法。方法利用微量苯酚-硫酸法对西瓜翠衣多糖含量进行测定,葡萄糖为标准品,直接在96孔板进行加样操作,探讨检测波长、试剂添加顺序及用量、显色时间等因素对吸光值的影响,并测定了精密度、稳定性、重复性和回收率。结果微量苯酚-硫酸法测定西瓜翠衣多糖条件优化结果为:检测波长为490 nm,6%苯酚溶液25μL,浓硫酸125μL,室温,反应时间10 min。用该方法测定西瓜翠衣多糖方法稳定,精密度高,在1~5μg范围内吸光度与被测物含量呈良好线性关系,r^(2)=0.999,平均回收率为104.68%,相对标准偏差为4.29%。结论优化后的微量苯酚-硫酸法测定西瓜翠衣多糖具有高通量,精密度高,稳定性和重复性好的特点,同时操作方便,快速,节约试剂,为西瓜翠衣多糖的快速检测奠定了基础,对其他多糖快速测定具有参考价值。

外源EBR对NaCl胁迫下西瓜种子萌发及幼苗生长的影响

以西瓜优良品种“早佳8424”为试材,用不同浓度的EBR对NaCl胁迫下的西瓜种子进行浸种处理和西瓜幼苗喷施处理,研究在NaCl胁迫下不同浓度2,4-表油菜素内酯(EBR)对西瓜种子萌发、幼苗生长和生理特性的影响,以期筛选出适宜的EBR浓度应用于生产实践。结果表明:在150 mmol·L^(-1)NaCl胁迫下,适宜浓度的EBR对西瓜种子的发芽势、发芽率具有显著缓解作用,0.05 mg·L^(-1)EBR处理显著提高盐胁迫下西瓜幼芽生长后的下胚轴长、主根长及鲜质量。在盐胁迫下,西瓜叶面喷施0.05 mg·L^(-1)EBR能显著促进幼苗的根长、株高、叶长与叶宽的增长;EBR处理后的西瓜幼苗丙二醛(MDA)含量与只施加150 mmol·L^(-1)NaCl的处理相比显著降低,西瓜幼苗根系活力、超氧化物歧化酶(SOD)活性和过氧化物酶(POD)活性、脯氨酸含量在0.05 mg·L^(-1)EBR浓度处理下显著高于其他EBR浓度处理。综上所述,0.05 mg·L^(-1)EBR处理能显著促进盐胁迫下西瓜种子萌发和幼苗的生长,可为西瓜生产遇到的盐胁迫问题提供参考依据。

不同耐热型西瓜幼苗对高温胁迫的生理响应

为探究高温胁迫对不同耐热型西瓜自交系的影响,以热敏感型(D27)和耐热型(K53)西瓜幼苗为试验材料,在42℃高温胁迫下持续处理48 h,每12 h取样测定分析幼苗的表型、组织结构、光合特性、抗氧化酶活性和渗透调节物质等生理指标。结果显示,在高温胁迫后,耐热型K53的叶片厚度、栅栏组织厚度、海绵组织厚度和组织紧密度均比热敏感型D27大;D27栅海比的下降幅度大于K53。随着高温胁迫时间的增加,2个自交系的净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)均下降,胞间CO 2浓度(Ci)上升;且D27的变化幅度大于K53。在4个光合色素含量中,高温胁迫下,不同处理时间耐热型均高于热敏感型。2个自交系的超氧化物歧化酶活性(SOD)、过氧化物酶活性(POD)随着高温胁迫时间的增加均先升后降,24 h酶活性最大,且K53的酶活性均显著高于D27。高温胁迫后,2个自交系的相对电导率均升高,K53的相对电导率上升幅度小于D27;D27的丙二醛(MDA)含量降低;K53的MDA含量升高后降低。随着高温胁迫的时间增加,24 h时K53的可溶性蛋白含量和脯氨酸含量(Pro)均显著高于D27。综上所述,耐热型K53较热敏感型D27具有较强的抵抗高温胁迫能力。

叶面预喷施水杨酸缓解西瓜幼苗高温胁迫的生理效应

【目的】探讨叶面预喷施不同浓度水杨酸(SA)对西瓜幼苗高温胁迫伤害的缓解效应及其生理机制,为SA在西瓜栽培和生产中合理应用提供理论基础。【方法】以温室内盆栽‘K53’西瓜幼苗为试验材料,先叶面喷施不同浓度(0,0.5,1.0,1.5,2.0 mmol/L)SA,后经昼夜42℃胁迫36 h,观测西瓜幼苗生长特性、解剖结构及生理生化指标,并用隶属函数法综合评价各处理的缓解效应。【结果】在高温胁迫后,西瓜幼苗叶片萎蔫严重,根长生长受到抑制,叶片变薄、叶肉细胞结构受损。施加SA后叶片变厚,光合色素含量、光合气体交换参数、抗氧化酶(POD、SOD、CAT)活性及渗透调节物质(脯氨酸、可溶性糖、可溶性蛋白)含量显著升高,MDA含量和相对电导率显著下降。与高温胁迫处理相比,1.0 mmol/L SA处理叶片的MDA含量和相对电导率分别显著降低33.70%、58.58%,叶绿素a含量、叶绿素b含量、净光合速率及SOD、CAT活性分别显著升高22.71%、21.63%、98.34%、23.98%和19.71%。【结论】叶面预喷施不同浓度的SA均能有效缓解西瓜幼苗高温胁迫伤害,并以1.0 mmol/L SA处理效果最佳。

含硝化抑制剂复合肥对西瓜 黄瓜产量和营养品质的影响

采用田间试验研究了含硝化抑制剂3,4-二甲基吡唑磷酸盐(3,4-dimethylpyrazolephosphate,DMPP)复合肥(ENTEC,12-12-17)对西瓜(CitrulluslanatusM.)、黄瓜(CucumissativusL.)生长和品质的影响。结果表明,含DMPP复合肥可以显著提高西瓜、黄瓜产量,与对照(普通复合肥)相比,分别提高6.50%(浙蜜1号)、44.55%(浙蜜2号)、8.40%(津春4号),均达到了显著性水平。西瓜、黄瓜的硝酸盐含量与对照相比,分别降低了2.42%(浙蜜1号)、10.70%(浙蜜2号)、27.44%(津春4号)。西瓜、黄瓜的糖分、可溶性固形物、VC、氨基酸、N等含量都明显提高,从而提高了营养品质。从总的趋势来看,含DMPP复合肥在西瓜浙蜜2号上的施用效果优于浙蜜1号。