Plantain Bananas PIF Seedlings Treatment with Liquid Extracts of <i>Tithonia diversifolia</i>Induces Resistance to Black Sigatoka Disease

Plantain bananas culture encounters the problems of seedlings quantity and quality unavailability. Black Sigatoka Disease (BSD) is one of the main pathological constraints of banana that can severely reduce the photosynthetic leaf area, leading to the losses of production of about 50% in banana plantation. The use of liquid extracts of Tithonia diversifolia could potentially induced the resistance of the PIF seedlings to BSD during the vegetative stages in the nursery. The aim of this work was to evaluate the effect of Tithonia diversifolia liquid extracts against the development of BSD on the PIF plantain bananas seedlings. The explants in the greenhouse and the seedlings in the shade were watered with liquid extracts of T. diversifolia during the process of PIF seedling production in sterile and non-sterile conditions. The treated seedlings show a more effective enhancement of seedlings quality parameters and also induce resistance against BSD. The vegetative stages parameters (the number of shoots, the diameter and the height of shoots, the foliar area, the length and weight roots) were improved in treated seedlings compared to controls ones. The treated seedlings showed maximum protection against BSD of up to 87% compared to controls. They also exhibited an increase in the accumulation of total proteins and total phenolics, as well as the activity of defense-related enzymes (peroxidase, polyphenol oxidase and glucanase). The treatment seems to acts as a vital stimulator and could therefore be a useful tool for small holder farmers favouring an eco-friendly agriculture using fewer synthetic inputs.

The Effects for Delaying Banana Seedling Growth through Spraying Growing Retardants on Stem Apex

Replanting is always required for banana farmers. Selecting growth retardants is important for banana seedling companies. Stem apex contained many gibberellins. Seven treatments were performed onto stem apex of banana seedlings in this research. Results showed that heights of seedlings sprayed with paclobutrazol (200 mg/L), dniconazole (200 mg/L), and dniconazole + brassins (200 mg/L + 0.1 mg/L) were significantly lower than those of seedlings sprayed with water. Paclobutrazol was the ideal retardant for delaying the growth of leaf if stem apex was selected as a treated candidate. Fresh weights of seedlings of all seven treatments were significantly less than that of control. For delaying the growth of fresh weight of banana seedlings, chlormequat chloride (200 mg/L) was the best choice. Reducing power of roots of seedlings treated with 100 ml of paclobutrazol (200 mg/L) was significantly higher than that of seedling treated with water. Chlorophyll contents of seedlings treated with growth retardants were significantly higher than that of seedlings treated with water.

A Method for Prolonging Culturing Time of Banana Seedling in Nursery Shed

Banana industry plays important roles in the economics of southern China, where is always blown by typhoon in summer and autumn. After typhoon passed through, fresh banana seedlings are often required. That is a problem for companies on culturing banana seedling, since culturing banana seedlings takes about four months and typhoon cannot be predicted so early. If the growth of banana seedlings can be slowed down and the seedlings can be cultured in nursery shed for more time, this problem will be solved. In this research, seven treatments (paclobutrazol, diniconazole, paclobutrazol + brassins, paclobutrazol + diethyl aminoethyl hexanoate, diniconazole + brassins, diniconazole + diethyl aminoethyl hexanoate, chlormequat chloride) were performed on banana seedlings and the growth was measured. Results showed that in all of the treatments, the values of plant height, leaf length, pseudostem diameters, root length, root weight, root volume, fresh weight of above-ground tissues and fresh weight of seedlings were significantly less than those corresponding values of control. The reducing powers of roots of seedlings sprayed with paclobutrazol and paclobutrazol + diethyl aminoethyl hexanoate were remarkably higher than those of seedlings treated with water. Total chlorophyll content in leaves of seedlings sprayed with paclobutrazol was remarkably higher than that of seedlings treated with water. Total chlorophyll contents in leaves of seedlings treated with paclobutrazol + diethyl aminoethyl hexanoate and chlormequat chloride were lower than those of control. For delaying the growth of banana seedlings, chlormequat chloride was the best among the seven treatments. The mechanism might be that the enzyme CPP-synthase in seedlings was inhibited by chlormequat chloride.

A Method to Predict Banana Pseudostem’s Strength at Seedling Stage

Banana industry played important roles in Chinese economics. Banana production was always affected heavily by typhoon. Selecting new cultivars with high strength was the basic way to resolve this problem. If the selecting work was performed at mature stage, it will need large area and much labor. If this work can be done at seedling stage, this process will be simplified significantly. We found that banana plants that had high strength at seedling stage always had high strength at mature stage. The physical strength of seedling pseudostem was closely related with pseudostem diameter, lignin content and the expression of 4-coumarate:CoA ligase gene Mu4CL15. Those seedlings whose pseudostem had bigger diameter, more lignin content and higher expression of Mu4CL15 always had higher strength to resist lodging. Through screening plants whose pseudostem had bigger diameter, more lignin content and higher expression of Mu4CL15, plants with high-strength pseudostem can be selected. Using this method, thousands of seedlings can be identified in short time. This process does not need large area and much labor. If this method was applied, the process of breeding new cultivars of banana with high resistance to lodging will be accelerated.

Constraints, and Implications of Organic Farming in Bananas and Plantains Production Sustainability in Benin

Bananas and plantains production is an important income source for millions of small farmers. The increased demand for bananas and plantains on national and international market would justify its value chain development. However, its value chain faces several constraints, of which production and marketing turn out to be the most important. This study aimed at determining and analyzing the constraints related to Bananas and Plantains value chain and showing the gaps between agroecological and agricultural practices used by farmers in southern Benin. Characterization was carried out on the seed production systems, agricultural practices, bananas and plantains production, fruit availability and commercialization constraints with farmers using individual and focus groups surveys. Bananas and plantains seedlings production and acquisition varied according to production areas. Their seedlings self-production was widespread in production areas and 26 cultivars have been identified as major. The availability of these cultivars varied across time and production areas. There were significant negative effects of agricultural practices on major banana pest’s presence. Bananas and plantains production was limited by 12 factors, from which banana plants fall related to the wind, lack of financial support to irrigate banana fields, climate changes, no availability of cultivable lands and low rainfall are revealed to be the most important. Regarding commercialization constraints, low sale prices and difficult access to markets were the most important. Better knowledge of bananas and plantains production systems would help to develop sustainable organic farming strategies to reduce the constraints identified.

多效唑与诱抗剂互作对香蕉苗生长及抗枯萎病能力的综合效应

【目的】明确多效唑(PP333)与水杨酸(SA)、茉莉酸(JA)、壳聚糖(CTS)和苯并噻二唑(BTH)等药物互作对香蕉苗生长及抗病性的影响,为利用诱抗剂防控香蕉枯萎病(Fusarium wilt of banana)提供参考依据。【方法】以香蕉品种‘宝岛蕉’组培杯苗为试验材料,叶面喷施PP333(A处理)及4种常用诱抗剂单剂(B、C、D和E处理)和双剂(A+B、A+C、A+D和A+E处理),以喷清水为对照(CK),结合伤根浸菌接种法,比较分析各处理香蕉苗的生长状况、抗枯萎病能力和防御酶活性。【结果】处理后30 d,各药物处理香蕉苗的株高均显著低于CK(P<0.05,下同),茎粗总体上高于CK。其中,双剂处理中以PP333配施BTH的株高最低,较CK显著降低31.84%,以PP333配施JA的茎粗最粗,较CK显著增加20.55%。双剂处理香蕉苗的地上部干物质量均显著低于CK,降幅为2.46%~5.74%,根系干物质量较CK显著提高39.02%~43.90%。各药物处理香蕉苗期的枯萎病病情指数均显著低于CK,其中PP333配施BTH和CTS对香蕉枯萎病的诱抗效果较佳,分别达57.63%和50.85%;双剂处理对诱导香蕉苗体内抗性相关酶活性的效应明显,其中,PP333分别配施BTH和CTS,其苯丙氨酸解氨酶(PAL)活性较CK分别提高54.59%~101.69%和42.09%~103.50%,多酚氧化酶(PPO)活性分别提高77.29%~228.77%和66.07%~267.65%,过氧化物酶(POD)活性分别提高121.82%~204.16%和54.31%~117.55%,超氧化物歧化酶(SOD)活性分别提高107.45%~263.51%和110.00%~301.07%,CAT活性分别提高141.95%~442.16%和192.68%~304.70%。【结论】PP333与诱抗剂互作可提高香蕉苗防御酶活性,壮苗效果好,对香蕉枯萎病具有良好的诱抗效果。其中,PP333与BTH和CTS配施的诱导效果更佳,具有生产应用前景。

菌土接种法在香蕉枯萎病苗期抗性评价中的应用及效果

【目的】建立一套稳定可靠且更符合自然条件下发病的香蕉枯萎病苗期抗性鉴定方法,为香蕉枯萎病抗性种质的筛选评价提供参考。【方法】以尖孢镰刀菌古巴专化型4号生理小种(Fusarium oxysporum f. sp. cubense 4,Foc4)为供试病原菌,分别采用伤根淋菌接种法、浸根接种法及菌土接种法接种感病香蕉品种巴西蕉,比较分析不同处理种植基质中病原菌孢子浓度的动态变化及植株发病情况,优选最佳的接种方法。采用Foc4不同孢子浓度菌土接种抗、感种质材料,统计发病情况,比较抗性评价效果;应用菌土接种法对31份香蕉种质进行枯萎病苗期抗性鉴定,考察其评价效果。【结果】采用不同接种方法,巴西蕉杯苗种植基质中Foc4孢子浓度变化、发病率和病情指数存在较大差异,其中,采用菌土接种法,种植基质中Foc4孢子浓度稳定保持在原始接种浓度1.0×10^(6)~1.1×10^(6)个/g土;采用浸根接种法,种植基质中Foc4孢子浓度呈先升后降的变化趋势,并于21 d达最大值(1.0×10^(6)个/g土),28 d降至0.5×10^(6)个/g土,35 d后稳定在0.4×10^(6)个/g土;采用淋菌接种法,种植基质中Foc4孢子浓度在0~14 d内由1.5×10^(6)个/g土迅速下降至0.5×10^(6)个/g土,35 d后稳定在0.6×10^(6)个/g土。接种42 d后菌土接种法的蕉苗发病率及病情指数均最高,分别为98.9%和67.3,浸根接种法次之,分别为86.7%和51.6,淋菌接种法发病率及病情指数均最低,分别为76.7%和44.1。在Foc4孢子浓度为1.1×10^(4)、1.1×10^(5)、1.1×10^(6)个/g土条件下,采用菌土接种法的高感品种巴西蕉发病率均在80.0%以上,高抗种质GCTCV-119的发病率分别为16.7%、35.6%和54.4%。在孢子浓度为1.1×10^(4)个/g土条件下,巴西蕉及GCTCV-119外观发病症状均不明显;综合高感和高抗品种(系)的发病情况,菌土接种法Foc4孢子浓度宜在1.0×10^(5)~1.0×10^(6)个/g土。采用菌土接种法对31份香蕉种质进行抗性评价,其中有中抗种质11份、感病种质14份、高感种质6份。【结论】菌土接种法具有稳定、准确、高效、简便、可操作性强的特点,可作为香蕉枯萎病苗期抗性评价及抗性种质筛选的优选方法。

绿色木质素/环氧树脂基双层包膜尿素的研制及对香蕉幼苗生长的影响

将木质素天然材料作为制备包膜尿素的膜层原料,并成功构建无溶剂木质素基包膜尿素的制备工艺体系。以木质素、辛酸亚锡、六亚甲基异氰酸酯和聚乙二醇为原料,通过调控—NCO/—OH的摩尔比和液固比研制木质素基膜材,以此研制包膜尿素的内层包膜材料。在此基础上,将环氧树脂基包膜液作为外层包膜材料喷涂在木质素基包膜尿素颗粒表面,通过重复喷涂固化数次,即可得到不同包膜率的绿色木质素/环氧树脂基双层包膜尿素。通过调控—NCO/—OH的摩尔比、液固比和包膜率来探究包膜尿素的最佳工艺条件。同时,通过静水培养试验测试其累积氮素释放率,选择最优氮素释放性能的包膜尿素,评估其表面形貌和抗压性能之间的差异。最后,通过香蕉盆栽试验评估包膜尿素的肥效。结果表明,膜材水接触角与—NCO/—OH摩尔比和液固比呈正相关。在—NCO/—OH摩尔比为1.50、液固比为3.19和包膜率为6.99%的条件下包膜尿素的氮素释放性能最优,其28 d的累积氮素释放率为62.26%。与常规尿素相比,该研究制备的包膜尿素有效提高了香蕉幼苗的株高、茎粗、鲜重、干重多项指标,同时提高了肥料的氮素利用率。

不同浓度NaHCO_(3)处理对香蕉叶片生理指标的影响

以巴西蕉幼苗为试验材料,分析不同浓度NaHCO_(3)对香蕉幼苗叶片生理指标的影响,探究香蕉幼苗的耐碱性盐特性。以胁迫处理20d后的相对株高生长量为因变量(Y)、以NaHCO_(3)浓度为自变量(X)建立回归曲线方程,相对株高生长量下降50%时所对应的盐浓度即为巴西蕉幼苗对胁迫的耐受阈值,确定其耐盐阈值为89.3mmol·L^(-1)。结果表明,巴西蕉幼苗对碱性盐胁迫有一定的耐受性,高浓度碱性盐胁迫下幼苗无法正常生长,为后续探索香蕉幼苗耐盐机制提供理论依据。

不同规格椰糠基质对袋装组培香蕉苗生长的影响

为筛选出较适合培育组培香蕉苗的椰糠规格,本文研究了6种不同规格的椰糠基质对组培香蕉苗的影响。结果表明,不同规格椰糠基质对组培香蕉苗茎粗、株高、叶宽、叶片数、地上部鲜干重和地下部鲜干重影响显著;通过"壮苗指数"法对不同规格椰糠基质的应用效果进行评估,以含椰丝量较少的椰糠基质(处理2)为最佳。

香蕉高效组培快繁技术的研究

【目的】改良传统的香蕉组培快繁技术提高优良种苗繁育效率。【方法】通过香蕉外植体的选取和芽诱导处理方法、芽的分化及培养、丛生芽壮芽处理、生根培养、组培苗栽培获得健康幼苗的技术过程进行优化改良。【结果】对传统吸芽处理及培养方法进行改良,使每个吸芽材料第一代出芽数量达26.4个,比传统处理方法第1代出芽数量(2.2个)提高效率12倍;生产相同数量的组培苗生产周期与传统处理法相比缩短3代。优化了不定芽分化培养基6-BA浓度和生根培养基中蔗糖的浓度,建议芽分化培养基中6-BA最适浓度为4 mg·L-1;生根培养基蔗糖最适浓度为40 g·L-1。利用椰糠、泥炭土和红壤土三种栽培基质培育组培苗,椰糠处理的幼苗叶数、株高和假茎基部直径、植株根干重和地上部干重各生长参数均显著高于泥炭土和红壤土处理,可作为重要的无土栽培介质而广泛应用。【结论】研究为提高香蕉组培快繁效率及培育健康优良种苗提供了实用指南,有利于香蕉产业的可持续发展。

水分胁迫对巴西香蕉幼苗水分状况、质膜透性和根系活力的影响

在盆栽试验条件下，以巴西香蕉幼苗为试材，设置7个水平土壤含水量处理，分别为100％～91％、90％～81％、80％～71％、70％～61％、60％～51％、50％～41％和40％～0，测定叶片相对含水量、组织含水量、自由水、束缚水含量、质膜透性和根系活力。研究结果表明，随着水分胁迫的加剧，叶片相对含水量、组织含水量、自由水含量和根系活力均随土壤相对含水量的下降而减少；而水分饱和亏缺、束缚水含量和质膜透性则随土壤相对含水量的下降而升高。综合不同处理下巴西香蕉幼苗水分状况、质膜透性和根系活力可知，香蕉幼苗生长最适宜的土壤水分含量是田间持水量的71％～80％。

基于正交试验的香蕉组培苗栽培基质筛选

采用正交试验法,以巴西品种香蕉组培苗为试材,以新叶叶面积和、假茎高、生物量为考察指标,筛选香蕉组培苗栽培的最优基质。结果表明,最利于香蕉假茎高生长的基质配比为A3B4C2D2,即椰糠:泥土:有机肥:河沙=2:4:0.05:0.1;最利于香蕉苗生物量累积的基质配比为A3B4C2D1,即椰糠:泥土:有机肥:河沙=2∶4∶0.05∶0。因C与D处理组不存在显著差异,且正交设计选取了A3B4C2D1组合做为代表性试验,故本试验选择A3B4C2D1,即椰糠:泥土:有机肥:河沙=2∶4∶0.05∶0为最佳配比。

缺钾对香蕉苗期地上部、根系生长及氮磷钾吸收的影响

【目的】明确香蕉苗缺钾的表型症状,探讨缺钾和恢复供钾对香蕉苗生长及氮磷钾营养平衡的影响,为香蕉苗营养诊断和平衡施肥提供依据。【方法】通过石英砂培养试验,以正常的完全营养液为对照,观察记录香蕉苗缺钾的表型症状及出现时间,对比研究缺钾和缺钾后恢复供钾条件下香蕉苗的地上部和根系的生物量、根系形态参数、氮磷钾吸收等变化。【结果】缺钾的表型症状为:老叶发黄,中部叶片主叶脉先呈现橙黄色,并逐渐向叶缘蔓延,然后部分叶片叶缘出现近椭圆形小枯斑,叶柄呈现浅红褐色,缺钾严重时,橙黄色叶片近叶脉处的叶肉发黑,进而干枯死亡,枯叶呈褐色,完全展开的新叶不挺立,上部叶片柔弱、下披。缺钾显著抑制香蕉苗生长,缺钾处理较正常处理的地上部和根系生物量降低了31%和39%,其根长、根表面积和根体积减少了30%、31%和34%,且细根减幅大于中根。缺钾同时改变了香蕉苗氮磷钾平衡,其地上部、根系和全株的氮含量分别增加了19%、21%和19%,磷含量分别增加了40%、12%和38%,钾含量分别降低了73%、56%和72%,氮、钾吸收量降低,根系的磷吸收量降低;缺钾处理的地上部、根系和全株的N/K、P/K显著升高,地上部和全株N/P显著降低,根系N/P显著升高。缺钾后恢复供钾,香蕉苗缺钾表型症状消失,但香蕉苗的生物量以及氮、磷、钾含量和吸收量不能同步恢复,香蕉苗生物量仍低于正常处理,各部位的氮含量、根系的磷、钾含量仍高于正常处理,地上部和全株的钾含量和吸收量也未增加至正常水平。供钾后地上部和全株的磷吸收量显著降低,且低于正常处理。【结论】缺钾对香蕉苗营养状况的影响显著大于对表型性状的影响,营养状况的恢复滞后于表型性状的恢复,香蕉苗施肥要针对其营养特性施用。

不同基因型香蕉苗期钾效率差异的初步研究

本文在营养液砂培养条件下,对16个香蕉基因型苗期进行了钾效率筛选研究.结果表明,不同基因型之间钾效率存在显著差异,变幅为0.34 ～0.62.高效基因型与低效基因型相比,在低钾条件下,生长状况优势更明显,表现为出现缺钾的症状慢,叶片脱落晚,植株较大;施钾能明显促进香蕉的生长发育,提高于物质积累,干物质分配趋势是地上部大于根部;与干物质积累相似,在低钾处理时高效基因型的钾积累量较高,表明其在低钾时具有较高的钾吸收能力.

外源一氧化氮对香蕉幼苗抗冷性的影响

以巴西香蕉(MusaAAA Group Cavendish cv.Brazil)幼苗为试验材料,采用外源一氧化氮(NO)供体硝普钠(SNP)15μmol.L-1溶液进行冷胁迫(8℃)前处理,考察其冷胁迫和常温恢复过程中抗冷性指标的变化,以探讨外源NO对香蕉幼苗抗冷性的影响。结果表明,在8℃冷胁迫环境下,SNP预处理香蕉幼苗的萎蔫程度较轻,且在常温下恢复快而完全。SNP预处理可以显著降低冷胁迫下香蕉幼苗叶片的质膜相对透性及过氧化氢和丙二醛含量,并显著增加其可溶性蛋白含量。在冷胁迫的前2 d,SNP处理苗的过氧化物酶和抗坏血酸过氧化物酶的活性显著增加,而超氧化物歧化酶和过氧化氢酶的活性则在胁迫的第3天才显著上升,经3 d冷胁迫回温(28℃)后,4种酶的活性均显著提高。可见,适当浓度NO能够通过诱导香蕉幼苗体内的抗氧化酶活性来有效缓解其遭受的冷胁迫损伤。

秋水仙素诱导抗枯1号香蕉多倍体试验

【目的】通过多倍体诱导途径为香蕉育种提供新型种质资源。【方法】以抗枯1号香蕉胚性细胞悬浮系(ECS)为材料,利用秋水仙素进行多倍体诱导,探讨在秋水仙素不同浓度、不同处理时间条件下多倍体的获得情况。【结果】在未采用秋水仙素处理的条件下,抗枯1号香蕉ECS在继代培养过程中存在一定比例的染色体数目自然变异,变异率为11.76%;而秋水仙素处理后再生苗的染色体数目变异率介于76.92%～100.00%,且有少量的嵌合体再生植株;不同浓度秋水仙素及处理时间获得的再生苗数及其变异率不同,其中以0.1%秋水仙素处理12h的效果较好,共获得3株六倍体植株,且能得到大量非整倍体变异。【结论】通过秋水仙素诱导香蕉ECS获得再生加倍值株是可行的。

冬春季节遮阴处理对香蕉假植苗生长的影响

冬季 (12～ 1月 )、春季 (3～ 4月 ) ,将从培养瓶中移出的香蕉组培苗置于大棚内 ,在 4种遮阴水平下进行假植炼苗 ,光照条件分别为 10 0 % (S10 0 ) ,33% (S33) ,10 % (S10 ) ,3 % (S3)。结果表明 ,不同光照强度下 ,香蕉苗的苗高、基径、叶长、叶宽、叶片数、叶面积、总根数和长根数都存在显著差异 ,但不同的性状对光照强度的反应不同。冬季有利于根系的生长 ,春季则更有利于地上部性状的生长。冬季和春季都以S33光照处理为最优 ,即适度遮阴有利于香蕉假植苗的生长发育。但春季各性状对遮阴水平适应的范围比冬季更宽 ,并且各性状在不同的季节对同一遮阴水平的反应也不相同 。

不同苗龄“威廉斯B6”香蕉组培生根苗生产同批假植苗的研究

结合生根培养苗龄、假植基质等因素,研究了不同假植基质对不同苗龄香蕉组培生根苗假植成活率以及对假植苗假茎高度、叶片数、根系数、根系长度等生长指标的影响;同时研究了不同苗龄的瓶苗于不同季节在椰糠+珍珠岩中假植成活率的变化情况。结果表明:相同苗龄的香蕉组培生根苗在不同基质中假植成活率有显著差异,在椰糠+珍珠岩的混合基质中假植成活率最高;不同苗龄也是如此;结合假茎高度、叶片数、根系数、根系长度等生长指标认为椰糠+珍珠岩为最优假植基质,在这一基质中假植成活率可达92%～99%,能够满足不同苗龄香蕉组培生根苗在不同季节对假植基质的要求。

外源甜菜碱对香蕉幼苗抗冷性的影响

研究了外源甜菜碱对香蕉幼苗抗冷性的影响,结果表明,外源甜菜碱能提高香蕉幼苗叶片的脯氨酸(Pro)含量,减少O2.-的积累,提高超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(ASP)的活性,维持质膜的稳定性,从而有效地提高香蕉幼苗的抗冷能力,其中以甜菜碱10.0 mmol/L的保护效果最好。