光质对马铃薯试管薯形成的影响

以两个试管薯形成能力不同的马铃薯脱毒试管苗为材料,研究不同光质(白光、红光、蓝光)对马铃薯试管苗生长和试管薯形成的影响.结果表明：红光下试管苗叶片的净光合速率、可溶性糖含量和生物量最高,试管苗叶片数多.蓝光对试管苗干物质含量和试管苗发育后期的结薯数量以及结薯期提前有明显促进作用,但对试管苗株高有明显抑制作用.白光下试管苗净光合速率和干物质含量最低.不同品种试管薯的形成对光质的要求有一定差异.总之,壮苗培养阶段采用红光,试管薯诱导阶段采用蓝光处理利于提高试管薯产量.     

黄独微型块茎低温离体保存的GC/MS代谢组学分析

GC/MS检测方法采用初步探明黄独低温离体保存微型块茎的差异代谢物。与黄独微型块茎25℃离体保存相比较,黄独微型块茎4℃离体保存的差异性代谢物有丙氨酸（Alanine）、儿茶素（Catechin）、N,N-双（2-羟乙基）甲胺（N,N-Di-（2-Hydroxyethyl）-methanamine）、水杨酸（Salicylic acid）、柠檬酸（Citric acid）和山梨糖（Sorbose）等。在黄独微型块茎4℃离体保存中,丙氨酸（Alanine）参与氰基氨基酸代谢;儿茶素（Catechin）参与次生代谢产物生物合成、黄酮类化合物的生物合成和苯丙素的生物合成;水杨酸（Salicylic acid）参与多环芳烃降解、微生物在不同环境中的代谢、植物激素信号转导、次生代谢产物生物合成、二恶英降解、苯丙氨酸代谢、芳烃降解、植物激素生物合成、铁载体组非核糖体肽合成和苯丙素的生物合成等。柠檬酸（Citric acid）参与来自鸟氨酸、赖氨酸和烟酸的生物碱生物合成、组氨酸和嘌呤的生物碱生物合成、微生物在不同环境中的代谢、植物次生代谢产物的生物合成、2-氧代羧酸代谢、萜类和类固醇的生物合成、原核生物固碳途径、次生代谢产物生物合成、来自莽草酸途径的生物碱生物合成、来自萜类化合物和聚酮的生物碱生物合成、柠檬酸循环（TCA循环）、植物激素生物合成、乙醛酸和二羧酸代谢、双组分系统、苯丙素的生物合成以及来自鸟氨酸,赖氨酸和烟酸的生物碱生物合成等。黄独低温离体保存微型块茎差异代谢物的初步发现为进一步了解其低温离体保存的分子机制奠定了基础,也为低温离体保存黄独微型块茎的破除休眠以及其后续萌发提供了理论依据。     

Micropropagation studies inCeropegia SPP

Summary The purpose of this study was to developin vitro techniques for conserving wild and endemic species ofCeropegia by mass multiplication for subsequent reintroduction in their natural habitat. Micropropagation involving a combination of axillary bud culture, shoot multiplication, somatic embryogenesis andin vitro tuber formation forCeropegia jainii, a rare plant of the Indian sub continent,C. bulbosa var.bulbosa andC. bulbosa var.lushii, common species, was developed. Nodal explants from all species were cultured on 0.5 MS medium with 8.8 μM (2 mg·l⁻¹) N⁶-benzyl aminopurine (BA) to regenerate the axillary buds. These produced multiple shoots when transferred to multiplication medium consisting of 0.5 MS medium with 2.2 μM (0.5 mg·l⁻¹) BA, or microtubers when transferred to 0.5 MS medium with 22.2 μM (5 mg·l⁻¹) BA and 23.2 μM (5 mg·l⁻¹) kinetin.In vitro flowering occurred inC. jainii and not in the other two varieties when the plants were cultured on multiplication media with spermine at 0.25 μM (50 μg·l⁻¹) as an additive. Shoot pieces produced callus on MS medium with 9.05 μM (2 mg·l⁻¹) 2,4-dichlorophenoxy acetic acid. Regeneration of the calli by somatic embryogenesis was achieved when they were transferred to 0.5 MS medium with 2.2 μM (0.5 mg·l⁻¹) BA. Rooting of the shoots was possible both byin vitro andex vitro means.     

In vitro propagation and cytology of wild yams,Dioscorea abyssinica Hoch. and D. mangenotiana Miège

Two wild yams of West Africa, Dioscorea abyssinica Hoch, and D. mangenotiana Miège were micropropagated from nodal cultures. Both species produced 4–5 nodes per each node cultured. The size of nodal cuttings was critical, segments shorter than 0.5 cm being less suitable for micropropagation. The number of nodes produced was constant even after 5 cycles of subculture; however, D. abyssinica continuous subculture decreased propagation efficiency, resulting in a reduced number of reculturable nodes at each cycle. In D. mangenotiana, the decrease in multiplication efficiency affected both the number of total and reculturable nodes. Large-sized microtubers were induced on nodal segments maintained under 8-h daylength in both species. In D. abyssinica, however, microtubers were induced on media containing 20, 40, 60 and 80 g l^-1 sucrose, whereas in D. mangenotiana only 40 and 60 g l^-1 sucrose favoured tuberization. Cytological studies confirmed that the chromosome number of D. abyssinica was 2n=40, although a high incidence of cytochimerism and cells with 2n=38 were observed in root meristems. In D. mangenotiana clones, the chromosome number was 2n=40, as against 2n=72 and 2n=80 reported in literature. This species also displayed karyological stability.Abbreviations BA benzyladenine - NAA naphthaleneacetic acid - PPF photosynthetic photon flux     

黄独微型块茎低温保存及其萌发苗遗传稳定性研究

以黄独微型块茎为材料,对其低温保存期间的解剖结构、生理生化指标进行观察,并对其低温保存后的萌发苗进行遗传稳定性检测。结果表明:低温保存时间越长,微型块茎外围细胞内的淀粉粒消失越多,至90d时,淀粉粒消失的细胞扩延到微型块茎中部;低温保存期间,微型块茎的抗氧化酶和淀粉酶活性及其脯氨酸和可溶性糖含量均呈显著增加趋势。在低温保存的0~90 d内,SOD活性在18~54 d内持续增加,而在54~90 d内基本维持不变;POD活性在18~36 d内显著增加,在36~54 d内维持稳定,而在54~72 d内又开始显著增加,72~90 d趋于稳定;CAT活性变化趋势与SOD活性一致,即在18~54 d内持续增加,而在54~90 d内基本维持不变;α-淀粉酶和总淀粉酶活性在18~36 d内快速增加,在36~54 d内无显著变化,在54~90 d内持续显著增加;β-淀粉酶活性在18~54 d内显著增加,在54~72 d内维持稳定,在72~90 d内又开始显著增加;可溶性糖含量在18~36 d内显著增加,36~54 d内无显著性变化,54~90 d又开始显著增加;脯氨酸含量在18~36 d内无变化,在36~72 d内显著提高,在72~90 d内维持不变。微型块茎低温保存90 d后,其萌发苗的形态(株高、叶片数、根数和茎节长)、DNA含量、生理指标(总叶绿素含量、SOD活性、CAT活性、POD活性、可溶性糖含量和可溶性蛋白含量)及其叶片的光合特性参数(净光合速率、气孔导度、细胞间CO2浓度、蒸腾速率、气孔限制值、水分利用效率和瞬时羧化速率)和叶绿素荧光参数(初始荧光、最大荧光、PSⅡ最大光化学效率、PSⅡ潜在光化学效率、PSⅡ实际光化学效率、开放的PSII反应中心捕获激发能效率、光化学荧光猝灭系数和非光化学猝灭系数),与常温保存的比较均无显著性差异,这表明黄独微型块茎的低温保存不会造成植株的遗传变异。     

Microtuber formation in micropropagated Jerusalem artichoke (Helianthus tuberosus)

Clonal micropropagation of Jerusalem artichoke (Helianthus tuberosus L.) was initiated from axillary meristems of lateral shoots of field-grown plants on medium with MS salts, 2% sucrose, 1 mg l-1 thiamine-HCl, 1 mg l-1 IAA and 0.6% agar. Plantlets were cut into nodal sections and used for subsequent subcultures and for microtuber induction. Microtubers were induced from axillary meristems on medium with half-strength MS salts, 8% sucrose and 0.5 mg l-1 BA in darkness at 18 °C. They had near to 30% of dry matter. Microtubers resumed growth in light room at 23 °C after 4–6 months of cold storage. This revised version was published online in June 2006 with corrections to the Cover Date.     

The effect of gamma irradiation on potato microtuber production in vitro

The effects of low doses of gamma irradiation and potato (Solanum tuberosum L.) cultivar on the production of microtubers in vitro were investigated. Nodal segments from virus free explants of three potato cultivars (cv.) were placed on tuberization inducing medium and irradiated with 4 doses of gamma radiation (2.5, 5, 10, 15 Gy). Cv. Diamant produced the highest number of microtubers followed by Draga and Spunta. Irradiation of the explants with 2.5 Gy of gamma radiation led to a significant increase in the number of microtubers (38% increase over the control). Average weight of microtubers was not significantly influenced by low doses of gamma irradiation. Draga microtubers were the largest followed by Diamant and Spunta. Microtubers resembled mature tubers in shape (Spunta was oval and Draga and Diamant were spherical). Size of microtubers was crucial for sprouting in vivo. It is suggested that only microtubers larger than 5 mm in diameter (250 mg) be used to produce minitubers in vivo. Since 2.5 Gy is a low irradiation dose, it can be used to enhance tuberization in vitro without fear of genetic changes in the used cultivars. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of salinity on physiological characteristics,yield and quality of microtubers <Emphasis Type="Italic">in vitro</Emphasis> in potato

In vitro microtuberization provides an adequate experimental model for the physiological and metabolic studies of tuberization and the preliminary screenings of potential potato genotypes. The effects of saline stress at 0–80 mmol concentration on in vitro tuberization of two potato cultivars were investigated in this study. With an increase in the salt concentration, the microtuberization of potato was either delayed by 5–10 days (20 and 40 mmol NaCl) or inhibited completely (80 mmol NaCl) in addition to the reduction in microtuber yields. The two potato genotypes studied showed different trends in total soluble sugars, sucrose and starch contents of microtubers under NaCl stress, while glucose and fructose levels remained unchanged. The vitamin C content in microtubers of two potato genotypes was reduced by salt stress. Salinity applied from 20 to 60 mmol progressively increased proline and malondialdehyde (MDA) levels in microtubers of both the potato cultivars. In genotype Zihuabai, NaCl at a low concentration (20 mmol) led to a significant increase in peroxidase (POD) and polyphenoloxiadase (PPO) activities, while in Jingshi-2, the PPO activity decreased progressively with an increase in NaCl concentrations. Genotype Zihuabai exhibited higher tolerance to salt stress than Jingshi-2 under in vitro conditions. These results could be used for preliminary selections of salt tolerance in potato breeding programmes.     

Microtuberization of layered shoots and nodal cuttings of potato: The influence of growth regulators and incubation periods

A protocol is presented for the rapid induction of microtubers on micropropagated, layered potato shoots of Kennebec, Russet Burbank and Superior in medium devoid of growth regulators. Layered shoots microtuberized more rapidly and produced significantly larger microtubers compared with nodal cuttings. The addition of coumarin or (2-chloroethyl)-trimethylammonium chloride and benzyladenine to microtuberization medium, either had no effect or significantly reduced microtuber weight per shoots compared with medium containing only 80 g × 1^-1 sucrose and minimally affected the number of microtubers per shoot. Increasing the incubation period from 28 to 56 days did not affect the number but significantly increased the weight of microtubers per shoot and substantially increased the proportion, up to 20%, of microtubers heavier than 1 gram.Abbreviations Ba benzyladenine - ccc (2-chloroethyl) trimethylammonium chloride - coumarin 2h-1-benzopyran-2-one - ga₃ gibberellic acid