Comparative Analysis of Tuber Development in Six Sweet Potato (Ipomoea batatas (L.) Lam) Cultivars: 1. Tuber initiation, tuber growth and partition of assimilate

Differences in tuber initiation, tuber growth and partitionof assimilate during development were investigated in six localsweet potato cultivars. Study of the quantitative morphogenesisof root types in the sweet potato root system indicated thattuber initiation was completed by 8 weeks after planting inmost cultivars and frustrated thereafter. Subsequent differencesin patterns of tuber development were not obviously relatedto final tuber yield. Thus, high yield resulted either froma short period of rapid tuber growth or a longer period of slowertuber growth. Maximum shoot growth was achieved by week 12 inall except one cultivar, and the cessation of shoot growth resultedin either increases or decreases in tuber growth rate or hadno affect on the rate of tuber growth (cv. A28/7). The partitionof assimilate to tubers at final harvest was the parameter mostclosely related to the yield of the six cultivars studied, butthere was some evidence that such partition was related to totaldry weight. It is suggested that limiting factors in sweet potatotuber yield, e.g. assimilate production and transport or capacityfor tuber growth varied with the cultivar studied.     

Comparative Analysis of Tuber Development in Six Sweet Potato (Ipomoea batatas (L.) Lam) Cultivars: 2. Interrelationships between tuber shape and yield

Interrelationships between tuber dimensions and yield duringdevelopment of six sweet potato cultivars with different tubershapes were examined. Maximum tuber lengths and tuber stalklengths were attained after 16 and 8 weeks of growth, respectively.Rates of increase in tuber width in the 16- to 24-week periodand final tuber widths were related to the mean tuber weightand yield of the cultivars studied, e.g. rates were highestin the high yielding cv. O₄₉ and low in cv. A16/15. Relationshipsbetween parameters of tuber development, tuber dimensions, sinkstrength and yield were evaluated and tuber width appeared tobe the most important single dimensional determinant of highyield. However, tuber shape in cv. 03/62 was different fromother cultivars and this cultivar was an exception in the interrelationshipsdescribed. Some factors known to affect tuber shape and developmentwere discussed.     

甘薯叶绿体rbcL基因的克隆与序列分析

根据烟草、水稻和菠菜叶绿体的全基因组序列设计引物,以甘薯的叶绿体基因组DNA为模板,PCR扩增包舍甘暑叶绿体rbcL完整基因(GenBank登录号为AY942199)在内的一段序列.序列分析表明:此片段的全长为1 627 bp,包括1 443bp的编码区序列在内.推测编码480个氨基酸,同时构建了此片段的限制性酶切图谱.相似性比较显示,此基因编码区序列与烟草、菠菜、小麦、水稻、玉米、矮牵牛、紫花苜蓿、拟南芥、莨菪、葡萄以及甜菜的rbcL基因核苷酸的同源性为85%～98%,氨基酸的同源性为92%～95%.     

The Development of Alternative Storage Sink Sites in Sweet Potato Ipomoea batatas

Sweet potato plants were found to develop three alternativestorage sink sites: adventitious roots, replanted tubers andstems, indicating that the capacity for tuberization is notlimited to the root system. In each case, sink development occurredas a result of meristematic activity of the vascular cambiumand anomalous cambia associated with differentiating vascularbundles in the pith. The involvement of environmental, anatomicaland physiological parameters in the tuberization of sweet potatois discussed. Ipomoea batatas, sweet potato, tuberization, sink site     

The Anatomy of the Root System in West Indian Sweet Potato (Ipomoea Batatas (L.) Lam.) Cultivars

The comparative anatomy of different root types including tuberousroots and tubers in the root system of a West Indian sweet potatocultivar cv. 049 is described, and tissue distribution in maturetubers compared with five other local cultivars. Anatomicalevents leading to tuber initiation and tuber growth to maturityare outlined and the anatomical specialization of the sweetpotato tuberous root, particularly in the development of translocatorytissues in the ‘tuber stalk’ and in adventitiousbud genesis, is described. Possible relationships between theanatomy of tuber development and final tuber yield are discussed.     

The Effects of Drought Stress and Leaf Ageing on Leaf Photosynthesis and Electron Transport in Photosystem 2 in Sweet Potato (Ipomoea batatas Lam.) Cultivars

Of the four tested sweet potato cultivars having different features in growth and yield, cv. Koganesengan (KOG) was sustainable in photosynthetic activity through young to aged leaves under drought. One of the causes for this phenomenon may be stomatal conductance (g _s) of this cultivar that was relatively high in both aged and drought-imposed leaves. In these leaves the non-photochemical quenching (NPQ) was low and the quantum yield of photosystem 2 (Φ_e) was high, compared to those of the other cultivars. This helps to prevent excessive accumulation of chemical energy in leaves and a decrease in photoinhibition damage to the photosynthetic function, by which KOG sustains a relatively high photosynthetic activity under the drought and alleviates functional deterioration caused by leaf age. This revised version was published online in August 2006 with corrections to the Cover Date.     

Chemical and environmental growth regulation of sweetpotato (Ipomoea batatas (L.) Lam.) in vitro

The need for conservation of biotic diversity is well recognized. However, improved techniques for the efficient, cost effective-preservation of plant germplasm are needed. The conservation and distribution of plant germplasm in vitro is gaining acceptance. However, increased usage is dependent upon the ability of curators to minimize culture maintenance requirements. This report examines the effect of various levels of sucrose, photoperiod, temperature, sorbitol and mannitol on minimal growth storage of Ipomoea batatas (L.) Lam. Growth was reduced 50% with a temperature reduction of from 21.1 to 15.6°C. Sucrose concentrations of 15 and 20 g l^-1 resulted in reduced plant stature with few adverse effects on plantlet viability or morphology. Reduction of photoperiod from 16 to 4 h produced smaller, slightly chlorotic, but otherwise normal plants. The addition of sorbitol or mannitol to culture media generally produced undesirable effects on gross plant morphology and loss of apical dominance. Genotype x growth retarding treatment interactions were observed for all variables examined.Abbreviations PL plant introduction - f.w. fresh weight - SE standard error     

Plant regeneration from protoplast culture of sweet potato (Ipomoea batatas Lam.)

This is the first report on successful plant regeneration from protoplasts of sweet potato. Two cultivars (Guyana and Duclos XI) of sweet potato plants propagated under in vitro conditions were used as the source of protoplasts. Green compact calli with meristematic areas were induced in the medium supplemented with 2mg1^–1 zeatin, and plant regeneration occurred when these calli were transferred onto the medium with zeatin level reduced to 0.25mg1^–1. Plant regeneration was found to be genotype-dependent, since it was only obtained for cultivar Duclos XI.Abbreviations MS Murashige and Skoog basal medium - IAA Indol-3-acetic acid - NAA naphthaleneacetic acid - 2,4-D dichlorophenoxyacetic acid - Mes 2-(N-morpholino)-ethanesulfonic acid - Cpw cell and protoplast washing solution     

甘薯基因组 TCP转录因子鉴定与逆境胁迫表达分析

基于甘薯( Ipomoea batatas ( L.) Lam.)全基因组序列, 利用生物信息学方法鉴定筛选了全基因组中的TCP( teosinte branched1/cincinnata/proliferating cell factor)转录因子, 并分析了甘薯苗期在蔓割病菌胁迫及块根储藏期低温胁迫下TCP基因的...     

Effects of Chemical Growth Retardants on Growth and Development of Sweetpotato (Ipomoea batatas (L.) Lam.) in Vitro

Plant growth retardants were evaluated for their ability to reduce the growth rate of sweetpotato (Ipomoea batatas (L.) Lam.) in vitro. Nodal sections of cv. Jewel were cultured for 30 days on medium containing NDA, ancymidol, phosfon, TIBA, difenzoquat, chlormequat, ACC, mepiquat chloride, or daminozide at 0, 10⁻⁴, 10⁻⁵, 10⁻⁶, 10⁻⁷, or 10⁻⁸ m. Difenzoquat, NDA, phosfon, and TIBA, at 10⁻⁴ m, were lethal to axillary bud explants. A low concentration (10⁻⁸ m) of chlorflurenol or NDA stimulated shoot elongation. The effective concentration range for most growth retardants was 10⁻⁵ to 10⁻⁶ m. Small (2- to 4-mm diameter) storage root-like swellings were observed on roots in cultures containing TIBA or ancymidol. The growth-inhibiting effects of ancymidol and NDA were transitory and did not persist through a 180-day culture period. Shoots cultured on medium containing 10⁻⁵ m phosfon, TIBA, or difenzoquat were significantly shorter than control plants after a 180-day culture period. Culture on medium containing TIBA, NDA, ancymidol, or ACC resulted in abnormal leaf and stem development. Plants derived from nodal explants cultured on medium containing either phosfon or chlormequat were near normal in appearance but with some plants exhibiting interveinal chlorosis and reduced root system development. Received May 9, 1997; accepted August 14, 1997     

发根农杆菌介导药用甘薯西蒙1号的遗传转化

用发根农杆菌A4分别感染药用甘薯西蒙1号的叶片、茎切段、叶柄等外植体,诱导出毛状根,并对毛状根进行了离体培养.采用L9(34)正交设计法优化甘薯西蒙1号的毛状根诱导条件;PCR扩增检测转化毛状根;用高效液相色谱仪检测了毛状根中咖啡酸的含量.结果表明:转化中茎切段是最合适的外植体,最佳感染时间20 min,共培养最佳时间为2天;PCR扩增检测表明发根农杆菌Ri质粒的T-DNA片段已整合进植物的基因组中;经高效液相色谱仪证实毛状根中含有咖啡酸,含量为0.03792 mg/g.     

Electron Microscopy of an Isometric Caulimo-Like Virus from Sweet Potato (Ipomoea batatas)

A newly recognised virus with isometric particles 50 nm in diameter was detected in Ipomoea batatas (sweet potato) by graft-transmission to I. setosa. Virus particles and intracellular inclusions, although not seen in infected I. batatus, were found in the cytoplasm of most cell types of I. setosa. The caulimo-like particles were most abundant with vesicles immediately adjacent to inclusions. The ovoid or spherical inclusions, which differ markedly from those of caulimovi, ruses, have a large central lacuna and usually several smaller peripheral lacunae. Infected vascular parenchyma cells sometimes protrude into, and occasionally completely occlude, adjacent xylem vessels, observations possibly explaining the sudden wilting and premature senescence of infected leaves.     

Phosphate fertiliser alters carboxylates and bacterial communities in sweet potato (Ipomoea batatas (L.) Lam.) rhizosheaths

Plant and Soil - Selenium (Se) is an essential element for mammals and its deficiency in the diet is a global problem. Plants accumulate Se and thus represent a major source of Se to consumers....     

Anomalous Growth in the Stem of Ipomoea batatas (L.) Lam. Infested with Megastes Larvae

The stem of Ipomoea batatas (L.) Lam. is characterized by thepossession of a ring of bicollateral, leaftrace bundles. Lacticifersoccur in the pith, in the parenchyma between neighbouring islandsof medullary phloem, and in the cortex. The xylem groups become united by the activity of the inter-fascicularcambium. The production of a certain amount of secondary xylemtakes place before the production of secondary phloem begins.The former is produced more extensively in some areas than inothers, so that the original symmetry of the vascular cylinderis lost. The phellogen originates in the cells of the epidermis. When the stem is attacked by the larvae of Megastes grandalisGuen., which remove most of the internal tissues, anomalousgrowth takes place as a result of the activity of accessorycambia, which develop in the primary cortex, the secondary phloem,and the phelloderm. Residual parenchyma of the pith and/or xylemundergoes hyperplasia to produce a callus tissue which linesthe cavity made by the larvae.     

The Effects of an Arabinogalactan-Protein from the White-Skinned Sweet Potato (Ipomoea batatas L.) on Blood Glucose in Spontaneous Diabetic Mice

We examined the effects of an arabinogalactanprotein (WSSP-AGP) from Ipomoea batatas L. on hyperglycemia in db/db mice. An oral glucose tolerance test indicated significantly decreased plasma glucose levels by WSSP-AGP. Additionally, an insulin tolerance test found improvement in insulin sensitivity due to treatment with WSSP-AGP. This suggests that amelioration of insulin resistance by WSSP-AGP causes to lead its hypoglycemic effects.     

Comparative Transcriptome Analysis of Hybrid Population Provides Insights Into Starch Content in Sweet Potato (Ipomoea batatas L.) Storage Root

Plant Molecular Biology Reporter - Sweet potato is an important starchy crop, which is mainly utilized as food, animal feed, and fermented to produce fuel-grade alcohol. However, the genetic...     

Changes in Levels of Butanol- and Water-Soluble Cytokinins during the Life Cycle of Potato Tubers

The nature of the water-soluble cytokinin in potato tubers (Solanumtuberosum L.) and the changes in the levels of both butanol-and water-soluble cytokinins during their life cycle were examined.The main cytokinin detected in the water-soluble fraction hadthe same chromatographic behavior and susceptibility to enzymesas zeatin ribotide. The level of butanol-soluble cytokinin inelongating stolon tips was low, while that of water-solublecytokinin was extremely high. Upon swelling of the stolon tips,the former increased greatly as the latter decreased. The resultssuggest that the increased butanol-soluble cytokinin is responsiblefor the subsequent vigorous thickening growth of the stolonsto form tubers and that the water-soluble cytokinin is a temporarystorage form. (Received February 6, 1982; Accepted May 13, 1982)     

Changes in caffeic acid derivatives in sweet potato (Ipomoea batatas L.) during cooking and processing

There was an obvious decrease in caffeic acid derivatives during the boiling of cube-shaped blocks of sweet potatoes. They also decreased in a mixture of freeze-dried sweet-potato powder and water maintained at room temperature. Ascorbic acid prevented the decrease, supporting the occurrence of an enzyme reaction with polyphenol oxidase (PPO). 5-O-Caffeoylquinic acid (5-CQA, "3-O-caffeoylquinic acid" as a trivial name) and 3,5-di-O-caffeoylquinic acid (3,5-CQA), major phenolic compounds of sweet potato, did not change when they were separately heated in boiling water. When the mixture of powdered sweet potato and water was heated at 100 degrees C, there was only a negligible decrease in the total amount of phenolic compounds, and portions of 5-CQA and 3,5-CQA were found to be isomerized to 3-CQA, 4-CQA, 3,4-CQA, and 4,5-CQA. The content and composition of the phenolic compounds in sweet potatoes differed between fresh and long-stored ones, as did their response to heating.