甜瓜翠雪7号高质量种子生产及加工技术研究

甜瓜种子质量决定出苗率、出苗整齐度和幼苗的健壮生长,继而影响甜瓜的产量以及品质。随着甜瓜育苗向集约化和规模化方向的发展,育苗场或者种植户对高质量甜瓜种子的需求也越来越高。基于对甜瓜种植密度、授粉数量、单株坐果数和采收时间等因素的分析以及基于木酢液可破除种子休眠特性,研究甜瓜品种翠雪7号高质量种子生产和加工处理技术,以期为厚皮甜瓜高质量种子生产提供借鉴。

弱光胁迫对不同甜瓜品种果实生理特性的影响

【目的】为揭示弱光胁迫对不同品种甜瓜果实主要品质特征的影响。【方法】研究‘西洲蜜1号’、‘早皇后’、‘伽师’3个甜瓜品种在不同光照条件(100%、42%、23%透光率)下,其果实不同部位(果梗、果基、果肉)碳水化合物、类胡萝卜素和叶绿素含量在不同发育时期(花后0、3、7、14、21、35、40、60 d)的变化。【结果】甜瓜果实淀粉、蔗糖、还原糖含量在果实发育过程中不断增加,且在成熟期(花后35 d)含量最高,其中‘西洲蜜1号’淀粉含量最高(10.835%),‘伽师’淀粉含量最低(8.342%)。3个甜瓜品种果肉和果基部分的蔗糖含量比果梗高,但还原糖含量无差异;类胡萝卜素和叶绿素含量在果实发育过程中增加,但在完熟期(花后60 d)下降。弱光胁迫显著降低甜瓜果实碳水化合物含量,增加类胡萝卜素和叶绿素含量,其中透光率23%处理影响最为显著,‘西洲蜜1号’甜瓜淀粉、蔗糖、还原糖含量最高降低了32.3、29.87、28.02,胡萝卜素、叶绿素含量增加了19.47、13.98%;‘早皇后’甜瓜淀粉、蔗糖、还原糖含量最高降低了32.63、25.09、20.24%,胡萝卜素、叶绿素含量增加了54.74、21.06%;‘伽师’甜瓜淀粉、蔗糖、还原糖含量最高降低了41.08、32.39、39.1%,胡萝卜素、叶绿素含量增加了55.20、31.79%。与‘西州蜜1号’和‘早皇后’甜瓜相比,‘伽师’甜瓜的淀粉、叶绿素含量最低,蔗糖、还原糖含量最高,弱光胁迫下其淀粉、蔗糖、还原糖量下降最为显著,类胡萝卜素和叶绿素含量增加最为显著,表明‘伽师’甜瓜受弱光胁迫影响最大,耐弱光性最差。【结论】弱光胁迫会降低甜瓜果实的商业品质,透光率越低品质降低越严重,而‘伽师’甜瓜对弱光胁迫最敏感。

农杆菌介导的厚皮甜瓜遗传转化体系的建立

【目的】遗传转化是进行基因功能验证的重要手段,构建较为完善、高效的厚皮甜瓜遗传转化体系,为基因功能验证和厚皮甜瓜种质改良提供技术支撑。【方法】以厚皮甜瓜B8为材料,用携带植物双元表达载体pQY002005的根癌农杆菌介导转化B8子叶诱导再生,通过探究影响甜瓜遗传转化过程中的重要因子的作用,建立以B8为基础的甜瓜遗传转化体系。【结果】以正常光周期培养3 d的无菌苗子叶节为外植体,对其进行微刷+10 s超声处理可提高农杆菌侵染效率,荧光芽获得率达29.6%;压力85 kPa的2次5 min的抽真空侵染方式(间隔1 min)侵染效果较佳;4 mg·L^(-1)的Basta较适宜筛选抗性植株。利用以上方法,单次转化120个子叶节外植体,可获得31个再生荧光芽,17株生根苗,通过PCR检测确定8株阳性苗,阳性率达58.8%,阳性植株获得率为6.7%。【结论】成功建立了以B8为材料的甜瓜高效遗传转化体系,为甜瓜关键基因功能验证和种质精准改良提供技术支持。

单一及组合引发剂对甜瓜种子萌发及幼苗生长的影响

以宁夏地区甜瓜主栽品种花兰柿老化种子为材料,选用3种引发剂(5 g·L^(-1)CaCl_(2)、2 g·L^(-1)MnSO_(4)·H_(2)O、1.25 g·L^(-1)水溶性壳聚糖)对甜瓜种子进行单一及组合渗透引发处理,探讨不同种类引发剂对甜瓜种子萌发及幼苗生长的影响,筛选最优的引发剂。标准发芽试验结果表明:单一和组合引发剂处理均能显著促进老化甜瓜种子发芽,其中,组合引发剂5 g·L^(-1)CaCl_(2)+2 g·L^(-1)MnSO_(4)·H_(2)O处理的甜瓜种子活力指数显著高于对照和其他处理。穴盘育苗结果表明:组合引发剂可提高甜瓜幼苗质量,显著增加幼苗的茎粗、总鲜质量、总干质量和壮苗指数,组合引发剂5 g·L^(-1)CaCl_(2)+2 g·L^(-1)MnSO_(4)·H_(2)O(T4)和5 g·L^(-1)CaCl_(2)+1.25 g·L^(-1)水溶性壳聚糖(T5)处理的壮苗指数分别是对照CK1的2.00倍和1.89倍。T5处理对幼苗叶片光合色素含量提升幅度最大,幼苗根系活力最高。主成分分析筛选结果表明T5处理效果最佳。本研究筛选出的组合引发剂能有效改善老化甜瓜种子活力,促进幼苗生长,增强幼苗素质,可为甜瓜高质量集约化育苗提供技术支持。

1-MCP复合杀菌剂对西州蜜甜瓜常温贮藏品质的影响

为了探究不同保鲜剂复合杀菌剂对甜瓜的保鲜效果,以西州蜜甜瓜为试验材料,研究了抑霉唑硫酸盐、ClO2、咪鲜胺、1-MCP、1-MCP复合抑霉唑硫酸盐和无菌水对甜瓜常温贮藏下品质的影响。结果表明,与对照无菌水相比,所有保鲜剂均可显著抑制甜瓜采后腐烂与失重,维持果实硬度和可溶性固形物含量,提升贮藏品质。1-MCP与1-MCP复合杀菌剂处理可显著抑制西州蜜果实的呼吸速率和乙烯释放速率,呼吸峰值较对照无菌水分别降低43.7%和37.5%,乙烯释放峰值较对照无菌水分别降低47.9%和53.7%,呼吸峰值和乙烯释放峰值出现时间均推迟3 d。其中1-MCP复合杀菌剂对果实可滴定酸和Vc含量保持效果显著,与对照无菌水相比,可滴定酸含量提高40.0%,Vc含量提高38.2%,对西州蜜甜瓜的保鲜效果最好。

无花果叶提取液复合保鲜膜的研制及其在甜瓜保鲜上的应用

【目的】研究一种无毒安全、绿色环保、廉价易得的植物源抑菌材料,并在甜瓜贮藏与保鲜中应用,为无花果叶提取液复合保鲜膜在甜瓜上的应用提供参考。【方法】优化具有抑菌效果的植物源材料无花果叶提取液的提取工艺,采用响应面法优化乙醇浓度、超声时间、料液比并分析对无花果叶提取液总黄酮取得率的影响。采用十字交叉法测定提取液对甜瓜采后主要病原菌镰刀菌、链格孢的抑菌效果,并将无花果叶提取剂与被膜剂海藻酸钠,抗氧化剂柠檬酸,助剂蔗糖酯进行复合,采用正交法优化各制剂对贮藏期甜瓜腐烂率和失重率的影响。【结果】获得无花果叶提取液的最佳提取工艺参数:乙醇体积百分比为79.73%、超声时间为36.81 min、料液比为1∶24。无花果叶提取液复合膜保鲜剂的最佳组成配方为80 mg/mL无花果提取液+1.5%海藻酸钠+500 mg/L柠檬酸+0.5%蔗糖酯。【结论】无花果叶提取液在抑制甜瓜采后主要病原真菌上效果显著,无花果叶提取液复合保鲜膜在减少甜瓜贮藏期腐烂率和失重率降低上效果明显,可作为甜瓜贮藏保鲜的新型绿色的植物源保鲜材料运用于甜瓜生产中。

9种杀菌剂对甜瓜细菌性果斑病的田间防效

为筛选高效低毒且对甜瓜细菌性果斑病防效较佳的农药试剂,以砂地甜瓜为研究对象,对9种高效低毒杀菌剂进行了田间筛选试验。结果表明,供试的9种药剂对甜瓜细菌性果斑病均具有一定的防治作用。77%硫酸铜钙可湿性粉剂500倍液第1次和第2次喷药7 d后防效均在70%以上,且第2次防效比第1次上升1.55个百分点,防治效果最佳。建议在白银市甜瓜果斑病防治中优先选用77%硫酸铜钙可湿性粉剂500倍液喷雾防治。

甜瓜果实不同部位矿物元素含量分析

以海南地区种植的9个甜瓜品种为试验材料,采用电感耦合等离子体质谱法在成熟期对果实4个部位(果皮、果肉、果心和种子)的矿物元素含量进行测定。结果表明,甜瓜果实不同部位矿物元素含量差异较大,17种元素中,K、Mg、P、Na、Fe、Zn含量较高,Cu、Mn、Al、Co、Ni、B、Se、Rb、Sr、Ba含量较低;4个部位中,Mn、Ba、Al、Ca、Sr元素在果皮和种子部位的含量高于果肉和果心部位,Co、Cu、Zn、Se、B、Rb、K、Mg元素在种子部位的含量高于其他3个部位;网纹瓜果皮的K、Mg、Na、P、Ca、Fe、Zn、Al、B含量高于薄皮瓜;光皮瓜果心的K、Mg、Na、Fe、Cu、Mn、Co、B含量高于薄皮瓜;薄皮瓜种子的P、Zn、B含量高于网纹瓜和光皮瓜。甜瓜果实的果皮和种子中矿物元素含量高,网纹瓜相比光皮瓜和薄皮瓜具有更高的矿物元素营养价值。研究结果为海南地区甜瓜的高效益农业开发提供了新思路,也为甜瓜的综合开发利用提供了参考依据。

有机肥替代化肥对设施甜瓜产量、品质和土壤肥力的影响

为减少化肥过量施用带来的土壤肥力下降,甜瓜产量降低、品质下降等问题,以红金蜜甜瓜为试验材料,通过田间小区试验,设计常规施肥(CON)、优化施肥(OPT)、优化施肥基础上有机肥替代15%化肥(OF1)和有机肥替代30%化肥(OF2)共4个处理,研究不同施肥处理对设施甜瓜产量、品质和土壤肥力以及经济效益的影响。结果表明,与CON处理相比,OPT、OF1和OF2处理的甜瓜产量分别增加了1.70%、5.58%和9.82%;VC含量分别增加了41.9%、86.1%和62.3%;硝酸盐含量分别减少了39.0%、49.1%和52.2%;可溶性固形物含量分别增加3.4%、9.4%和10.1%;有机酸分别降低21.3%、32.0%和30.7%;提高了甜瓜品质。有机肥替代化肥还能增加土壤肥力,与CON处理相比,OPT、OF1和OF2处理的有机质含量增加了6.4%、11.4%和15.5%,提高了土壤速效养分含量和养分活化系数,并降低土壤容重。从经济效益上来看,与CON处理相比,OPT、OF1和OF2处理的经济效益分别提高了1.23%(3349元·hm^(-2))、5.84%(15964元·hm^(-2))和11.5%(31492元·hm^(-2))。因此,在土壤地力较好的产区,有机肥替代化肥是提高设施甜瓜产量、品质、土壤肥力以及经济效益的有效措施,其中在优化施肥基础上,有机肥替代30%化肥的效果最好。

不同砧木嫁接甜瓜亲和性分析及对生长和果实品质的影响

为探明不同砧木与甜瓜嫁接的亲和性及其对甜瓜生长和果实品质的影响,从而筛选出适宜宁波地区亲和性和共生性好且果实品质优良的甜瓜嫁接砧木,以4个南瓜品种和2个甜瓜品种作砧木,以厚皮甜瓜品种东方蜜1号为接穗,研究分析了不同砧穗间的亲和性及对甜瓜生长和果实品质的影响。结果表明,京发嫁接王和思壮12号2个南瓜砧木的砧穗组合亲和性表现良好,嫁接成活率分别达到95%和94%,定植后25、35 d时,甜瓜茎粗分别为0.79、0.97 cm和0.78、0.98 cm,生长势表现均优于其他砧穗组合;以京发嫁接王砧穗组合的甜瓜产量最高,平均小区产量为34.4 kg,折合667 m^(2)产量为1909.19 kg,华砧四号砧穗组合的甜瓜产量最低,与京发嫁接王砧穗组合相比,减产15.12%;不同砧穗组合的甜瓜果肉颜色和质地均无明显差异,全为橘色和脆质,可溶性固形物含量也均较高;果肉厚度以华砧一号砧穗组合表现最佳,果肉口感以亲蜜二号和甬砧9号2个砧穗组合表现最好。综合分析,生产上推荐甜瓜砧木甬砧9号与东方蜜1号嫁接为首选。

春季厚皮甜瓜品种比较试验

为筛选适宜杭州地区春季种植的厚皮甜瓜品种,调查了6个厚皮甜瓜的生育期、果实外观性状、果实内在品质及产量,并进行了相关分析。结果表明,6个参试品种的果实内在品质和产量存在显著差异,其中酥灿1号熟期最早、产量最高,肉质松脆,口感细腻,风味好;翠雪7号果实一致性好,商品果率最高,中心糖含量最高,肉质松脆,口感细腻,品质好。综合来看,酥灿1号和翠雪7号综合性状好,适合在浙北地区推广。

不同设施栽培模式对甜瓜生长发育和环境因子的影响

为研究爬地和吊蔓2种设施栽培模式对甜瓜生长发育和环境因子的影响特开展本试验。试验结果表明,2种栽培模式的夜间空气温度与湿度的变化曲线基本重合,爬地栽培白天的空气升温速度和降温速度、空气湿度下降速度和增加速度均快于吊蔓栽培。2种栽培模式的夜间空气平均温度和平均湿度差异不明显;与吊蔓栽培相比,爬地栽培白天空气平均温度高2.08℃、昼夜平均温差高2.19℃,平均湿度低8.21个百分点。爬地比吊蔓栽培的盛花期提早2 d,成熟期提早4~6 d,可溶性固形物含量高1.46个百分点。爬地栽培的甜瓜叶色浓绿、小而厚,吊蔓栽培的叶色淡绿、大而薄;吊蔓栽培的节间长度、白粉病发病率均显著大于爬地栽培。吊蔓栽培的667 m^(2)产值和利润都明显高于爬地栽培。

Induces Resistance Against Fusarium and Pink Rots by Acibenzolar-S-Methyl in Harvested Muskmelon (cv.Yindi)

Acibenzolar-S-methyl （ASM） is a chemical activator of systematic resistance in many plants. The effect of preharvest and postharvest application of ASM was evaluated for its ability to induce resistance in muskmelon fruit. The results indicated that 50 and 100 mg L^-1 ASM or 1 mL L^-1 imazalil at 1 week or 1 day before harvest were effective in reducing the lesion area with 100 mg L^-1 ASM the most effective. No treatment inhibited the infection rate. The postharvest results showed that 50 and 100 mg L^-1 ASM, and 0.1 mL L^-1 imazalil were effective in reducing the lesion area with 100 mg L^-1 ASM the most effective. No treatment inhibited the infection rate. There was a clear time-dependent response of the fruit to postharvest ASM treatment, in which treatments applied 1, 3, and 5 day before inoculation provided the best results. ASM did not demonstrate any fungicide effect in vitro and suppressed lesion area in treated muskmelons, indicating that disease resistance was induced. The protection of ASM was associated with the activation of peroxidase （POD） in treated muskmelons.

Control of Postharvest Fusarium Rot and Trichothecium Rot in Harvested Muskmelon (cv. Yindi) by Harpin

Preharvest and postharvest application of Harpin was evaluated for its ability to induce resistance in muskmelon fruit and control rots. Preharvest treatments were 30 mg L^-1, 60 mg L^-1 Harpin or 1 mg L^-1 Imazalil either I week or I day before harvest. The CK was untreated. Fruit were then inoculated with Fusarium semitectum or Trichothecium roseum 48 h after harvest, and stored at 23± 1℃, RH （relative humidity） 50-60% for 4 d. All treatments were effective in reducing the lesion area with 60 mg L^-1 Harpin the most effectively. No treatments inhibited infection rate. Postharvest treatment was fruit dips of 30 mg L i, 60 mg L^-1 Harpin, 0.1 mg L i Imazalil. Fruit were inoculated with F. semitectum or T. roseum 24, 72, 120 or 168 h after treatment, and stored at 23 ± 1℃, RH 50-60% for 4 days. All treatments were effective in reducing the lesion area with 60 mg L^-1 Harpin the most effectively. No treatments inhibited the infection rate. Postharvest Harpin treatment induced the peroxidase activity increase, peroxidase activity reached maximum after 8 d and the activation lasted at least 10 d.

Postharvest ASM or Harpin Treatment Induce Resistance of Muskmelons Against Trichothecium roseum

Induced resistance was studied in muskmelons （cv. Yindi） inoculated Trichothecium roseum with postharvest 1,2,3- benzothiadiazole-7-carbothioic acid S-methyl ester （ASM） （100 mg L^-1） or harpin （50 mg L^-1） treatment. Both ASM and harpin significantly reduced lesion diameter in inoculated fruit. Lesion diameter was limited in the treated and untreated halves of the same fruit, indicating that the local and systemic resistance was induced. Inhibiting efficacy of elicitors lasted 7 and 5 days in the treated and untreated halves. The resistance increased by the chemicals was associated with the activation of peroxidase （POD） and chitinase （CHT）. The elicitors induced a significantly and progressively increasing activity of POD and CHT in the treated and untreated halves, and the activation lasted at least 5 days. The activities of POD isoenzymes increased in the treated fruit. However, no new enzyme band was found in the treated and untreated halves.

Effects of thiamine on Trichothecium and Alternaria rots of muskmelon fruit and the possible mechanisms involved

The effects of thiamine against pink and black spot rots caused by Trichothecium roseum and Alternaria alternata and modulation on the metabolism of reactive oxygen species （ROS） and phenylpropanoid pathway were investigated in this paper. In vitro test indicated that thiamine significantly inhibited mycelia growth and spore germination of T. roseum and A. alternata. Thiamine at 100 mmol L-1 effectively inhibited lesion development of muskmelon fruit inoculated with T. roseum or A. alternata, enhanced production rate of O2; and H2O2 content, activities of catalase （CAT）, ascorbate peroxidase （APX） and glutathione reductase （GR） in muskmelon fruit. Thiamine also affect phenylpropanoid pathway in muskmelon fruit by increasing the activities of phenylalanine ammonia lyase （PAL） and peroxidase （POD）, the content of total phenolic compounds, flavonoids and lignin. These results suggest that the effects of thiamine on pink and black spot rots in muskmelon fruits are associated with its direct fungitoxic against the pathogens and the modulation of O2- and H2O2 production, elimi- nating enzymes and phenylpropanoid pathway.

A Study of Oxalate-Induced Systemic Resistance of Muskmelon to Squash Mosaic Virus

By treatment with oxalate muskmelon cultivar “Wangwenxiang”, which is sensitive to squash mosaic virus (SqMV), develops systemic resistance to SqMV significantly. The challenge inoculation experiments indicate that the symptom of oxalate treated plants gets much slighter, the virus content is only 4% reduced to. The peroxidase activity increases by five times, three new isoperoxidases are induced, and lignin content increases by 82.9%. These results indicate that oxalate induces systemic resistance of muskmelon to SqMV while it induces increase of peroxidase activity, new isoperoxidases and content of lignin in the plants treated with oxalate.

Damping-Off of Festuca arizonica Caused by Fusarium

We report here a damping-off disease occurring at the seedling stage, resulting in severe loss of the seedling stands caused by an important soil-borne fungal pathogen, Fusarium oxysporum. Endophyte-infected plants appear to be more resistant to the damping-off disease than uninfected plants.

Isolation and Identification of Main Fungal Pathogens in Muskmelon in Open Field of Hubei Province in Summer

Fungal diseases often occur seriously in muskmelon in open field of Hubei Province in summer, especially in continuous cropping pattern, resulting in great economic losses. In this study, the pathogens of main fungal diseases in muskmelon in open field of Hubei Province were isolated, and they were identified by morphological and molecular techniques. The results showed that muskmelon fusarium wilt is a major disease in muskmelon in open field of Hubei Province in summer, and its pathogen was confirmed to be Fusarium oxysporum. In future studies, one pair of specific primers would be designed to detect different pathogenic races of Fusarium oxysporum so as to accelerate the detection and to shorten the detection time,thereby proving guidance for actual production.

Determination of Fusarium Species Associated with Onion Plants(Allium cepa)in Field in Burkina Faso Causing Damping-Off and Bulb Rots

Onion (Allium cepa L.) is the second most important vegetable crop in Burkina Faso and provides an important source of income for those involved in the sector. However, producers are facing significant pre-harvest and post-harvest losses. To date, knowledge of major diseases of the crop is limited, limiting the development of effective control strategies. The objective of this study was to test the pathogenicity of some species of Fusarium. To this end, 33 fungal isolates collected from onion plants in 17 localities and belonging to five Fusarium species were used to inoculate onion seeds and bulbs to determine the pathogenic species responsible for damping-off on seedlings and basal bulb rot in Burkina Faso. The virulence of pathogenic isolates was determined according to the percentages of seedling damping-off evaluated 28 Days After Sowing, and the extent of rot in millimetres on inoculated bulbs. The evaluation of isolates on seedlings revealed that the most pathogenic isolates belong to the species F. proliferatum (I29, I21, I37, I33, I31), F. thapsinum (I35) and F. solani (I38) which resulted in 58.33% - 70.83% of seedling damping-off. The most pathogenic isolates on bulbs belong to the species F. proliferatum (I4, I29, I32) and F. oxysporum (I52, I50, I16) which caused 21.67 to 25 mm of rot on bulbs. Isolate I29 was very virulent on both seedlings and bulbs. The isolates of F. fujikuroi species were all low pathogenic on seedlings but one of them, (I27), expressed average pathogenicity on bulbs.