Effects of Sodium Chloride Stress on Growth of Sweet Potato Plantlets in vitro and Ion Content

[Objective] This study aimed to investigate the salt-tolerance mechanism of sweet potato.[Method]Two sweet potato varieties of Xu 25-2(salt-tolerant cultivar)and Triumph 100(salt-sensitive cultivar)were treated by sodium chloride with the concentration of 0 mmol/L and 100 mmol/L.After 20 days,Na+ content and Na+/K+ ratio in the roots,shoots and leave were determined by the flame photometer,while dry weight and fresh weight of roots,shoots and leave in different varieties were also studied.[Result]The growth of two sweet potato varieties was inhibited under salt stress,so the plant became shorter,leaf and root became fewer,dry weight of roots and leave decreased,but seedlings of Xu 25-2 were inhibited slightly.Furthermore,Na+ content and Na+/K+ ratio in roots,shoots and leaves of two sweet potato varieties increased.Na+ content of salt-tolerant Xu 25-2 was low in roots,shoots and leaves,while Na+ content of salt-sensitive Triumph 100 was high in shoots and leave of seedlings,but the change range of Xu 25-2 was less than that of Triumph 100.[Conclusion]The lower Na+ content and Na+/K+ ratio in leaves under salt stress were the most important characteristics for salt-tolerance of sweet potato varieties.

Standardized Production Technology of Virus-free Seed Potato

The research reviewed standardized production technology of virus-free seed potato, including stem tip isolation, tissue culture seedling production, breeder＇s seed and protospecies production, and standard potato tubers＇ production, and concluded a set of standardized production technology for virus-free seed potato, in order to provide theoretical references for improving potato yield.

Effects of different LEDs light spectrum on the growth,leaf anatomy,and chloroplast ultrastructure of potato plantlets in vitro and minituber production after transplanting in the greenhouse

Light spectrum plays an important role in regulating the growth and development of in vitro cultured potato(Solanum tuberosum L.) plantlets. The status of potato plantlets at the end of in vitro stage influences the minituber production after transplanting. With 100 μmol m^-2s^-1 total photosynthetic photon flux density(PPFD), a light spectrum study of 100% red light emitting diodes(LEDs) light spectrum(RR), 100% blue LEDs light spectrum(BB), 65% red+35% blue LEDs light spectrum(RB), and 45% red+35% blue+20% green LEDs light spectrum(RBG) providing illumination at the in vitro cultured stage of potato plantlets for 4 weeks using fluorescent lamp as control(CK) was performed to investigate the effects of LEDs light spectrum on the growth, leaf anatomy, and chloroplast ultrastructure of potato plantlets in vitro as well as the minituber yield after 2 months transplanting in the greenhouse. Compared to CK, RB and RBG promoted the growth of potato plantlets in vitro with increased stem diameter, plantlet fresh weight, plantlet dry weight, and health index. Furthermore, BB induced the greatest stem diameter as well as the highest health index in potato plantlets in vitro. Root activity, soluble protein, and free amino acid were also significantly enhanced by BB, whereas carbohydrates were improved by RR. In addition, thickness of leaf, palisade parenchyma and spongy parenchyma was significantly increased by BB and RBG. Chloroplasts under BB and RBG showed well-developed grana thylakoid and stroma thylakoid. Unexpectedly, distinct upper epidermis with greatest thickness was induced and palisade parenchyma and spongy parenchyma were arranged neatly in RR. After transplanting in the greenhouse for 2 months, potato plantlets in vitro from BB, RB, and RBG produced high percentage of large size tuber. BB improved fresh and dry weights of the biggest tuber but decreased tuber number per plantlet. In addition, RBG increased tuber number as well as tuber fresh and dry weight slightly. Our results suggested monochromatic blue LEDs as well as combined red, blue or/and green LEDs light spectrum were superior to fluorescent lamp spectrum in micro-propagation of potato plantlets. Therefore, the application of RBG was suitable;BB and RB could be used as alternatives.

Transcriptome analysis reveals effects of red and blue lightemitting diodes(LEDs)on the growth,chlorophyll fluorescence and endogenous plant hormones of potato(Solanum tuberosum L.)plantlets cultured in vitro

Red and blue light illumination has been reported to significantly affect plantlet growth.Potato is an important food and feed crop in the world and potato plantlet cultured in vitro plays an important role in potato production.However,few studies have documented the effects of red and blue light on the growth of potato plantlets revealed at the transcriptome level.The objective of this study was to determine the growth and physiological responses of potato plantlets cultured in vitro under monochromatic red(RR),monochromatic blue(BB)as well as combined red and blue(RB)LEDs using the RNA-Seq technique.In total,3150 and 814 differentially expressed genes(DEGs)were detected in potato plantlets under RR and BB,respectively,compared to RB(used as control).Compared to the control,the DEGs enriched in"photosynthesis"and"photosynthesis-antenna proteins"metabolic pathways were up-regulated and down-regulated by BB and RR,respectively,which might be responsible for the increases and decreases of maximum quantum yield(F_(v)/F_(m)),photochemical quantum yield(φ_(PSII)),photochemical quenching(q_(P))and electron transfer rate(ETR)in BB and RR,respectively.Potato plantlets exhibited dwarfed stems and extended leaves under BB,whereas elongated stems and small leaves were induced under RR.These dramatically altered plantlet phenotypes were associated with variable levels of endogenous plant hormones gibberellin(GAs),indoleacetic acid(IAA)and cytokinins(CKs),as assessed in stems and leaves of potato plantlets.In addition,monochromatic red and blue LEDs trigged the opposite expression profiles of DEGs identified in the"plant hormone signal transduction"metabolic pathway,which were closely related to the endogenous plant hormone levels in potato plantlets.Our results provide insights into the responses of potato plantlets cultured in vitro to red and blue LEDs at the transcriptomic level and may contribute to improvements in the micro-propagation of potato plantlets cultured in vitro from the light spectrum aspect.

Generation of Virus Free Potato Plantlets through Meristem Culture and Their Field Evaluation

Different aspects of micropropagation through meristem culture for the production of virus indexed source plants, in vitro tuberization and field evaluation of the in vitro regenerated plants were studied on four commercial cultivars of potato (Solanum tuberosum L.) viz., Diamant, Cardinal, Shilbilati and Lalpakri. The investigation was conducted at Rajshahi, Bangladesh from December 2010 to March 2012 to produce virus-free potato plantlets through meristem culture, shoot multiplications with root induction as well as their acclimatization and evaluation of morphological characters and tuber yield under field condition. Shoot tips of 25 - 30 day old field-grown plants of above mentioned four cultivars were used for meristem isolation. After isolation, meristems of these varieties of potato were cultured on “M” shaped filter paper bridge in Murashige and Skoog (MS) liquid medium. Four different treatments of media formulations viz. 0.1 mg/L KIN + 0.1 mg/L GA3, 0.1 mg/L KIN + 0.5 mg/L GA3, 0.5 mg/L KIN + 0.1 mg/L GA3 and 0.5 mg/L KIN + 0.5 mg/L GA3 were used as plant growth regulators. From these formulations MS + 0.1 mg/L KIN + 0.5 mg/L GA3 was found to be the best for the primary establishment of meristem culture. The primarily established meristems were subcultured on to MS semisolid basal medium supplemented with four different treatment combinations of hormones viz. 0.5 mg/L BA + 1.0 mg/L IBA;0.1 mg/L KIN + 0.1 mg/L GA3;0.5 mg/L BA + 0.5 mg/L GA3 and 0.5 mg/L KIN + 0.5 mg/L GA3 were used to identify the suitable media compositions for shoot proliferation. Results showed that out of these four media treatments the formulation 0.5 mg/L BA + 0.5 mg/L GA3 was found to be the best suitable for shoot generation. Among the four cultivars of potato higher frequency of shoot proliferation (number of shoots/explant and longest shoot length) was observed in Diamant, though the highest shoot formation (76%) was recorded in Cardinal. Virus free in vitro grown potato plantlets were obtained through DAS-ELISA test and used substantially for micro-propagation. After gradual acclimatization of rooted plantlets of four potato cultivars, they were transferred into the field for cultivation and established successfully. It was observed from the field study of in vitro meristem-derived plantlets that there were no virus-affected plants. The virus-free exotic varieties were much superior in all vegetative attributes and yield compared to those of indigenous varieties with producing potato plants of normal height. In contrast, the indigenous varieties took a longer time to tuber initiation and maturity, lower plant height and number of leaves per plant, a higher number of tubers but a lower amount of tuber weight per plant, and poorer tuber grade than the exotic varieties. However, the variety Cardinal exposed the best performances in the context of survival percentage of plantlets (90%), days to tuber initiation (DTI), a number of leaves per plant (NL), tuber weight per plant (343.40%) and the percentage of rich tuber grade.

Study on Virus-free Breeding Technology of Potato Microtuber

It is the simplest,fastest and effective way to improve the yield level of potato by selecting high quality virus-free seed potato for field production and maintaining the original characters of virus-free minituber. Microtuber is featured by small volume,no pathogen,convenient storage and transportation,which can be induced in summer with high temperature and humidity,and overcome a series of problems such as poor survival rate of transplanted test-tube plantlets,and easy pollution of cutting tips. Therefore,it can replace conventional test-tube plantlets directly for reproduction. Meantime,if minitubers are sown ahead of time using cold frame,the growth stage of potato minituber will avoid the occurrence period of aphids. The use of gauze cover for insect prevention has good effect on maintaining the excellent characters of microtuber. The yield and quality of virus-free potato are greatly improved by means of virus-free culture of shoot tip seedlings,subculture propagation of virus-free seedlings,induction of microtubers by dark culture,cultivation of breeder’s seeds in greenhouse and screenhouse to preserve the characters of potato.

Correlations between delayed fluorescence of chlorophyll, metabolism and yield of plants. III. Influence of viral infection on field plants and new technology of clone selection of virus-free planting potato

At the end of potato plants vegetation virus in-fection induced both decrease in maximum amplitude of delayed fluorescence maximal amplitude and increase half time of its decrease, as well as reduction in the amount of stems, plants’ height and assimilation area surface, yield, acceleration of plants development and their early die-off. The differences of DF pa-rameters and yields between strongly and weakly infected plants increase in case of a combined virus infection. In industrial test of the selection of virus-free planting potato by the use of DF parameter, a rise in the yield and de-crease degree of viral infection of crops was obtained.

Research Progress and Prospect on Prevention and Control Measures of Sweet Potato Virus Disease

Sweet potato virus disease is a serious biological threat to sweet potato,which seriously affects the development of sweet potato industry in China.This paper gives a brief introduction to the main defensive measures of sweet potato virus disease,such as cutting of virus infection source,killing of viral transmission media,cultivation and application of virus-free sweet potato,use of antiviral agents,breeding of varieties with virus resistance,and mild strain cross protection,so as to provide some reference for this field.

碳离子束辐照对马铃薯组培苗生长及生理特性的影响

为研究高能碳离子束对马铃薯组培苗茎切段的影响,以马铃薯品种‘新大坪’的组培苗茎切段为研究材料,设置4个辐照剂量梯度对其进行辐照处理,测定植株致死率、生根率、侧芽形成率、形态变异率以及叶片生理指标,确定‘新大坪’组培苗茎切段的半致死辐照剂量。结果表明:辐照剂量与致死率之间的关系呈正相关性;组培苗茎切段的再生植株表型变化主要为叶片不对称、叶缘不规则、茎变异伸长、叶片丛生和叶片粘连等;随辐照剂量升高,超氧化物歧化酶、过氧化物酶和过氧化氢酶活性呈先升后降的趋势;丙二醛含量则呈先升后降,随后又升高的现象。利用线性回归方程计算‘新大坪’的半致死辐照剂量为20.37 Gy。

云南马铃薯不同品种(系)对马铃薯疮痂病的抗性分析

随着云南省马铃薯种植面积的扩大和种薯调运的频繁,质量监管不足导致马铃薯疮痂病的发生日益严重。本研究旨在评估云南省马铃薯主栽品种对该病害的抗性水平,并筛选出具有潜在抗病性的育种材料。为此,本研究收集了33份不同的马铃薯品种(系)材料,并通过组织培养方法培育组培苗,进而采用盆栽试验进行抗性评估。同时结合对大田主栽品种田间发病情况的调查。结果显示,供试的33份马铃薯品种(系)的组培苗接种疮痂病菌后,所有测试品种均出现了不同程度的病害,发病率58%~96.67%,其中I-1085品种的发病率最低,F37-2品种的发病率最高。病情指数分布在22.58~67.27之间,以Fx3品种的病情指数最低,F37-2的最高。本研究结果为云南省马铃薯抗疮痂病品种选育工作提供了重要的基础性数据和理论支撑。

Design and experiment of conical diversion virus-free potato minituber precision seed-metering device

In order to accelerate the development of sowing mechanization of virus-free potato minituber,a conical diversion virus-free potato minituber precision seed-metering Device was designed according to the structural characteristics and agronomic requirements of virus-free potato minituber.The device is mainly composed of conical turntable,transmission shaft,outer baffle of seed-metering Device,baffle,seed outlet,seed cleaning device,type hole,etc.The working principle of conical diversion precision seed-metering device for virus-free potato minituber was expounded,and the stress analysis of virus-free potato minituber in each region was carried out.By EDEM discrete element simulation software,the structure of the type hole is optimized to determine the optimal structure of the type hole and according to the physical characteristics of virus-free potato minituber,the single factor experiments of the effects of length of type hole,cone disc speed and cone disc angle on seed filling performance were completed.The orthogonal regression test was carried out with the length of type hole,cone disc speed,and cone disc angle as the test objects,and the leakage rate and qualified rate as the response indexes.The regression models of leakage rate,replay rate,and qualified rate were established,and the parameters of the regression model were optimized.The optimal parameter combination is that the length of type hole is 33.61 mm,the cone disc speed is 6.35 r/min,and the cone disc angle is 26.59°.Bench test was carried out under the optimal conditions,the leakage rate was 3.80%,the replay rate was 0.80%,and the qualified rate was 95.40%,which was basically consistent with the prediction results of the regression model,and met the requirements of precision sowing of virus-free potato minituber.

马铃薯品种茎段愈伤组织诱导和植株再生的研究

以2个马铃薯品种夏坡蒂和费乌瑞它茎段为外植体,研究了不同植物激素对马铃薯愈伤组织诱导及其不定芽分化的影响。结果表明,夏坡蒂和费乌瑞它的茎段最佳愈伤诱导组织培养基分别为MS+6-BA 2.0 mg/L+NAA 0.5 mg/L+GA30.5 mg/L和MS+ZT 2.0 mg/L+NAA 0.1 mg/L+GA30.5 mg/L,愈伤率均可达到100%;夏坡蒂和费乌瑞它的不定芽最佳诱导培养基分别为MS+ZT 2.0 mg/L+NAA0.1 mg/L+GA35 mg/L和MS+6-BA 2.0 mg/L+ZT 2.0 mg/L+GA35 mg/L,诱导率分别为52.38%和53.6%。结果为进一步转基因工作中高效植株的再生奠定了一定的基础。

不同培养方式对马铃薯试管苗生长与试管薯诱导的影响

应用4种不同的培养方式,分别就不同状态培养基、用量及添加时期对试管苗和试管薯的生长发育的影响研究结果表明,与固体培养基相比,采用液体培养基减量、分次添加使用方法试管苗各项生长指标均达极显著水平,茎粗增加0.89cm,单株有效节数增加2节,鲜物质量和干物质量分别提高了4.15g和0.27g,成苗天数减少5.5d。试管薯的结薯期提早2～3d,单株结薯数达到2粒,单薯重多为100～1000mg,且生产成本降低了72.42％。

基质酸度对马铃薯植株生理特性及微型薯结薯能力的影响

以移栽于蛭石中的马铃薯夏波蒂和费乌瑞它两品种的脱毒试管苗为试验材料,采用不同pH值〔3、4、5、6、6.5(CK)〕的MS营养液浇灌幼苗,研究基质pH值对马铃薯植株生理特性及微型薯结薯能力的影响。结果表明,马铃薯叶片中叶绿素含量、SOD活性、硝态氮含量、磷钾含量、微型薯结薯数和平均单株产量均随pH值的升高而增加,pH值6时达最大值,pH值3时值最小,且夏伯蒂品种的pH值6处理在叶绿素含量、SOD活性等性状方面与对照(pH 6.5)间差异显著;脯氨酸含量则随pH值的升高呈降低趋势,pH值6时最低,pH值3时最高。结果表明,pH值6是马铃薯植株生长及微型薯形成的最适酸度值。

低磷胁迫下马铃薯试管苗生长及生理指标变化研究

马铃薯试管苗在全价、60%磷素和30%磷素的MS培养基上培养,第20 d、40 d时测定生理指标。结果表明,低磷胁迫对马铃薯试管苗新叶和侧根发生以及根生长具有促进作用,且地上部和地下部鲜重小幅增加。30%低磷培养环境下,试管苗的细胞膜透性值、可溶性蛋白质和可溶性糖含量均较对照明显增加,而叶绿素含量则明显降低,差异达到极显著或显著水平。60%低磷处理下,这些指标的变化与对照基本相同,差异不显著,表明含60%P元素的MS培养基适宜马铃薯试管苗生长。

外源硅及脯氨酸对盐胁迫下马铃薯试管苗的影响

在无菌微生态环境下,对马铃薯试管苗进行盐胁迫和外源硅及脯氨酸处理。结果表明,盐胁迫能够明显降低试管苗苗高、根质量和鲜质量;低盐浓度(0.1%NaCl)能够促进根的伸长,但这种促进作用随NaCl浓度的升高而消失。外源硅能够促进低盐胁迫下试管苗根的生长、鲜质量和根质量的增加,并降低试管苗游离脯氨酸含量。外源脯氨酸对盐胁迫下试管苗的生物产量促进效应低于硅,但却明显提高了试管苗的叶绿素含量。试验证明:外源硅及脯氨酸能够显著缓解盐胁迫对试管苗所造成的伤害。

不同MS和B9浓度对马铃薯脱毒试管苗生长的研究

选用米拉、凉薯 97、金冠 3个品种和MS液体培养基 (全量、半量 )、B 9含量 (5mg/L ,1 5mg/L ,2 5mg/L)进行 3因素完全随机试验 ,调查各处理后脱毒试管苗的苗重、株高、茎节、根重和根数。其结果显示 :1 / 2MS培养基和B 9浓度为5mg/L时对脱毒试管苗的苗重和株高伸长有促进作用 ,但在试管苗茎节数的增加上因品种不同所选用的MS培养基成分含量及B 9浓度有差异。

B_9和PP_(333)对马铃薯试管苗生长的影响

研究了不同浓度的B9和PP333处理在室温与恒温培养条件下对马铃薯试管苗生长的影响。结果表明 :B9和PP333均可不同程度地抑制试管苗徒长 ,促使节间缩短、叶绿素含量增加 ,形成壮苗 ,同时有利于试管苗较长时间保存。相对于B9,PP333处理的效应更佳 ,促进组织中SOD活性增加可能是PP333促进马铃薯试管苗生长健壮 ,并适宜较长时间保存的机制之一。不同培养条件 (温度等 )

硫代硫酸银对二倍体马铃薯试管苗生长和生理特性的影响

植物组织培养中由于气体交换的限制,培养器皿中常伴有乙烯积累,影响植株形态建成和器官生长发育。以马铃薯二倍体品系HS66、ED13和DH401为试材,研究不同浓度(0、1、2、4、8mgL-1)硫代硫酸银(STS)对试管苗生长和相关生理指标的影响。结果发现,与培养基中不加STS相比,附加1mgL-1STS可增加试管苗叶面积和叶绿素含量,抑制气生根的产生;附加4mgL-1以上STS试管苗出现紫色色素沉积、叶片背面生成愈伤组织等畸形现象。试管苗可溶性蛋白、脯氨酸和丙二醛含量随STS浓度的增加呈先降后升的趋势,在培养基中附加1mgL-1STS时,3个品系试管苗的可溶性蛋白、脯氨酸和丙二醛含量均下降;附加2mgL-1STS时,DH401可溶性蛋白和脯氨酸含量及HS66丙二醛含量反弹升高;附加4mgL-1以上STS时,3个品系试管苗的可溶性蛋白、脯氨酸和丙二醛含量均随STS浓度的增加而增加。上述结果说明,低浓度STS可以缓解乙烯胁迫,促进试管苗正常生长,高浓度STS则造成试管苗生理及形态上的明显毒害。

马铃薯脱毒试管苗保苗与试管薯诱导条件优化

研究了不同外源激素组合对马铃薯脱毒试管苗保苗效果的影响,研究了培养基、温度、光周期的综合作用对试管薯发生的影响。试验表明,适合于试管苗保苗的液体培养基为MS+CCC 4.0 mg.L-1+6-BA 0.5mg.L-1+GA30.05 mg.L-1,适宜试管薯诱导的培养基和培养条件为:液体培养基MS+6-BA6.0 mg.L-1+白糖60 g.L-1+活性炭3 g.L-1,环境温度18℃,光照10 h.d-1。