In Vitro Propagation of Potato (Solanum tuberosum L.)

Potato shoots were propagated in vitro by placing nodes fromsprouted tubers on Murashige and Skoog type medium without hormones.The vigour of growth and the rate of node production increasedwith both day-length and temperature over the ranges 8–24h and 15–25 °C respectively. Propagation rates ofup to x 10 per month were obtained. In vitro plantlets spontaneouslyformed roots either in agar or liquid cultures. Plantlets leftin the culture jars for 3–4 months eventually senescedand formed small tubers in 16 and 24 h day-lengths. In a day-lengthof 8 h vegetative growth continued by branching and no tuberswere formed. Solanum tuberosum L., potato, tissue culture, propagation, temperature, day-length     

Growth Enhancement and Developmental Modifications of in Vitro Grown Potato (Solanum tuberosum spp. tuberosum) as Affected by a Nonfluorescent Pseudomonas sp

A plant growth-promoting rhizobacterium, designated Ps JN and isolated from onion roots, was identified as a nonfluorescent Pseudomonas sp. The percentage of similarity of Ps JN to P. gladioli (NCPPB 1891), P. cichorii (NCPPB 943), and P. viridiflava (NCPPB 635), as determined from 135 biochemical and physiological tests was 77, 70, and 66%, respectively. Ps JN persisted through successive generations of in vitro cultured potato plantlets, both as endophytic and epiphytic populations. In vitro inoculated potato (Solanum tuberosum) nodal explants produced plantlets with significant increases in root number (24-196%), root dry weight (44-201%), haulm dry weight (14-151%), and stem length (26-28%) as compared with noninoculated control plants. Bacterization also enhanced leaf hair formation (55-110%), secondary root branching, and total plant lignin content (43%). Other root colonizing bacteria or heat-killed cells of Ps JN had no significant effect on plant growth. Detached leaves from in vitro grown control plants, when exposed to 19°C and 50% relative humidity, lost 55% of their moisture content in 2.5 hours. Moisture loss by leaves of in vitro grown, bacterized plants, as well as greenhouse-acclimated, bacterized plants, and control plants, was less than 20%. Changes in stomatal closure appear to account for this difference.     

Transcriptomic Response of In Vitro Potato (Solanum tuberosum L.) to Piezoelectric Ultrasound

Plant Molecular Biology Reporter - As part of a wider project to assess the impact of ultrasound on in vitro plant growth, this paper aimed to determine whether the application of piezoelectric...     

Effects of the Temperature of the Rooting Zone on the Growth and Development of Roots of Potato (Solanum tuberosum)

In solution culture the effect of optimal (20 °C) and supra-optimal(30 °C) root-zone temperatures on root growth and root morphologyof six potato clones (Solanum tuberosum L spp) was studied Growthwas compared with sweet potato (Ipomoea batatas L) and cassava(Manihot esculenta Crantz) Significant genotypical differencesin the responses of potato roots to supra-optimal temperatureswere observed, indicating the potential for selecting heat tolerantpotato clones In both heat tolerant and heat sensitive clones,the size of the root system was reduced by supra-optimal root-zonetemperature This was principally a result of decreased numberand length of lateral roots The first symptom of heat damagewas a reduction in the rate of cell division, followed by cessationof root elongation Bending of the apical root-zone togetherwith the formation of root hairs on the inner (concave) andlateral roots on the outer (convex) side were other symptoms,these coincided with the loss of starch granules in the root-cap Potato, genotypical differences, root morphology, root growth, temperature, Solanum tuberosum L     

Mobilization of Seedpiece Nitrogen During Plant Growth from Aged Potato (Solanum tuberosum L.) Seed-tubers

A study was conducted to characterize patterns of mobilizationand translocation of seedpiece nitrogen (N) from single-eyeseedcores cut from 5 and 17-month-old potato seed-tubers. Differencesin mobilization efficiency were related to age-induced, morphologicaldifferences in plant development. Seedcores from older seed-tuberssprouted earlier and produced an average of 6.6 shoots per eyecompared to a single shoot from younger seed-tubers. Shoot vigour(d. wt per shoot) from 17-month-old was four-fold lower thanthat from 5-month-old seed-tubers following 25 d of growth.However, total shoot dry matter from older seedcores was two-foldgreater than that from younger seedcores. Differences in vigourper shoot were not explained entirely by differences in shootnumber. Rates and absolute amounts of free amino, soluble protein andtotal-N mobilized from 17-month-old seedcores were greater thanfrom younger seedcores. However, a higher degree of intersproutcompetition from older seedcores translated into a lower amountof mobilized N available to support growth of individual shoots.Furthermore, before seedcore N became limiting, concentrationof foliar N (mg g d. wt^–1) from older seedcores was lowercompared to that from younger seedcores, indicating a lowersink strength for N per unit increase in dry weight of the multipleshoots. Seedpiece N did not appear to limit shoot growth fromyounger seedcores. Age-induced loss of vigour on an individualshoot basis may thus be related to decreased sink strength andincreased competition among multiple shoots for seedcore N. Potatoes (Solanum tuberosum L.), seed-tuber age, nitrogen mobilization, plant growth potential     

The Influence of Nitrogen Supply on the Use of Nitrate and Ribulose 1,5-bisphosphate Carboxylase/Oxygenase as Leaf Nitrogen Stores for Growth of Potato Tubers (Solanum tuberosum L.)

Millard, P. and Catt, J. W. 1988. The influence of nitrogensupply on the use of nitrate and ribulose 1,5-bisphosphate carboxylase/oxygenaseas leaf nitrogen stores for growth of potato tubers (Solanumtuberosum L.).—J. exp. Bot. 39: 1–11. The capacity of field-grown potato plants to store N in theirleaves for re-use during tuber growth was studied in two experiments.Increasing the N application from 0 g to 25 g N m^–2 providedplants with more N than they needed for growth and so allowedaccumulation of N in their leaves, principally as nitrate andprotein. Ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO)concentrations increased by approximately 120% in response toN application. During tuber growth there was an export of nitrate-Nfrom the leaves of N-replete plants and of RUBISCO-N from bothhigh and low N plants. RUBISCO-N was mobilized more rapidlyfrom leaves than N from other proteins and, together with nitrate,in one experiment accounted for over 90% of the N lost fromthe leaves irrespective of the N treatment. The potential contributionof mobilization of N stored in RUBISCO to the N content of tubersat final harvest was calculated as being between 11–15%,and appeared to be unaffected by the N supply to the plants. The distribution of N accumulating within the canopy, in responseto N application was studied. Nitrate accumulated predominantlyin the lowermost (shaded) leaves, while reduced N (includingRUBISCO) was found mainly in the younger leaves at the top ofthe canopy. This is discussed in relation to the growth of theplant and the supply of N. Key words: Solanum tuberosum, nitrogen, nitrate, ribulose, 1,5-bisphosphate carboxylase/oxygenase, storage     

One-Leaf Cuttings as a Model to Study Second Growth in the Potato (Solanum tuberosum) Plant

Second growth is an important physiological disorder of thepotato (Solanum tuberosum L.) plant. A model system to studysecond growth was developed using one-leaf cuttings. Photoperiod,temperature, decapitation and leaf removal treatments were carriedout on the plants from which the cuttings were taken and onthe cuttings themselves. Tuberized, one-leaf cuttings takenfrom moderately-induced plants and exposed to 35 °C afterleaf removal showed 95% second growth within 10 d after treatmentinitiation. Conditions that promoted second growth also reducedstarch and dry-matter content, even in tubers that did not developsecond growth. Cuttings, second growth, potato, Solanum tuberosum L, cv, Bintje, Solanum tuberosum L. cv., Désirée, Solanum tuberosum L. cv., Russet Burbank, tuberization, starch content, dry-matter, heat, photoperiod, decapitation, leaf removal     

Differences in Nitrogen Metabolism During Growth of Plants from Aged Potato (Solanum tuberosum L.) Meristems

The effect of advanced meristem age on growth and accumulationof plant nitrogen (N) in potato (Solanum tuberosum L.) was studied.Etiolated plantlets, excised from sprouted, single-eye-containingcores from 7 and 19-month-old seed-tubers, were transplantedinto aerated nutrient culture. Rates of shoot and root dry matterand shoot soluble-N (which included nitrate-N) accumulationwere similar for plants from both meristem ages over a 30 dinterval of log-linear growth. The rate at which nitrate-N accumulatedwas consistently 17 per cent higher in shoots from 19-month-oldcompared to those from 7-month-old meristems. However, accumulationof free amino-N and soluble protein-N were 21 and 15 per centlower, respectively in shoots from 19-month-old meristems. Abuild-up of shoot nitrate, along with lower rates of accumulationof amino-N and soluble protein-N, suggests a lower capacityfor nitrate reduction during early growth of plants from oldermeristems. Furthermore, these effects can be attributed to age-inducedchanges in the meristem or bud tissue as the plants were separatedfrom the tuber tissue initially in the study. Long-term ageingof seed-potatoes apparently affects changes within meristemsthat translate into a lower capacity to accumulate reduced formsof nitrogen during early plant growth. Potatoes (Solanum tuberosum L.), meristem age, nitrogen metabolism, plant growth potential     

Nitrogen Partitioning Within the Potato (Solarium tuberosum L) Plant in Relation to Nitrogen Supply

Nitrogen uptake and partitioning have been studied in field-grownpotato crops which were subjected to N deficiency (no fertilizerN applied), or received large applications of N (20 g N m^–2)at planting. Isolation of part of the root system of the plantsallowed pulses of 1SN to be applied at three different stagesof crop development. Partitioning of ¹⁵N throughout the plantswas followed during a subsequent chase, to distinguish betweenthe use in tuber growth of recently absorbed N, and redistributionof N from the existing N capital of the plant When a pulse of ¹⁵N was applied 26 d after emergence (DAE),the distribution of ¹⁵N within the plant closely followed thatof total N for the duration of the chase, which finished 110DAE. Application of fertilizer N decreased the proportion of¹⁵N recovered in the tubers, while increasing that found inthe canopy, because of an increase in leaf growth, particularlyat the top of the canopy, after 69 DAE. When fertilized plantswere supplied with 18N 69 DAE, a greater proportion of ¹⁵N wasrecovered in new leaf growth during the subsequent chase, thanwhen the ¹⁵N was supplied earlier in the season. It appearsthat current uptake of N is used to augment N pools within thecanopy and, where appropriate, support leaf growth at the endof the season. In contrast, transfer of N into the tubers isby remobilization of the existing N capital, as leaves senesce.The results are discussed in relation to studies of N partitioningin potatoes and other crops Solatium tuberosum, nitrogen-15, uptake, partitioning, pulse-chase     

雷竹体细胞胚诱导的初步研究

以雷竹（Phyllostachys violascens）种胚为外植体, 脱分化产生愈伤组织, 愈伤组织诱导产生体细胞胚, 并发育成苗。实验结果表明： 愈伤组织诱导体细胞胚基本培养基为MS无机盐＋20 g·L^-1葡萄糖（glucose）＋10 mg·L^-1腺嘌呤（adenine sulfate）＋ 0.5 g·L^-1麦芽抽提物（malt extract）＋0.1 mg·L^-1 6-BA＋0.01 mg·L^-1氨氯吡啶酸（picloram）＋10 g·L^-1type A agar; 将基本培养基中的氨氯吡啶酸浓度升高至0.1 mg·L^-1即为愈伤组织诱导的最佳培养基, 早期子叶胚是愈伤组织诱导的最佳胚体; 愈伤组织在添加0.001 mg·L^-1TDZ和0.3 mg·L^-1ABA的愈伤组织最佳培养基上光照培养4周后, 去除其中的ABA, 并添加0.1 mg·L^-1NAA继续培养1个月, 体细胞胚数量最多可达87.43%, 该培养基是体细胞胚发生的最佳培养基; 将上述体细胞胚发生培养基中的6-BA浓度升高至1 mg·L^-1, 继代培养2个月后有小苗出现。组织学观察显示, 体细胞胚细胞核大、质浓且多数呈球形原胚状。     

Growth and Tuberization of Potato (Solanum tuberosum L.) under Continuous Light

The growth and tuberization of potatoes (Solanum tuberosum L.) maintained for 6 weeks under four different regimes of continuous irradiance were compared to plants given 12 hours light and 12 hours dark. Treatments included: (a) continuous photosynthetic photon flux of 200 micromoles per square meter per second cool-white fluorescent (CWF); (b) continuous 400 micromoles per square meter per second CWF; (c) 12 hours 400 micromoles per square meter per second CWF plus 12 hours dim CWF at 5 micromoles per square meter per second; (d) 12 hours micromoles per square meter per second CWF plus 12 hours dim incandescent (INC) at 5 micromoles per square meter per second and a control treatment of 12 hours light at 400 micromoles per square meter per second CWF and 12 hours dark. The study included five cultivars ranging from early- to late-season types: `Norland,' `Superior,' `Norchip,' `Russet Burbank,' and `Kennebec.' Tuber development progressed well under continuous irradiation at 400 micromoles per square meter per second and under 12 hours irradiance and 12 hours dark, while tuber development was suppressed in all other light treatments. Continuous irradiation at 200 or 400 micromoles per square meter per second resulted in severe stunting and leaf malformation on `Superior' and `Kennebec' plants, but little or no injury and vigorous shoot growth in the other cultivars. No injury or stunting were apparent under 12-dim light or 12-dark treatments. Plants given 12 hours dim INC showed significantly greater stem elongation but less total biomass than plants in other treatments. The continuous light encouraged shoot growth over tuber growth but this trend was overridden by providing a high irradiance level. The variation among cultivars for tolerance to continuous lighting indicates that potato may be a useful species for photoinhibition studies.     

Factors Affecting the Formation of In vitro Tubers of Potato (Solanum tuberosum L.)

In vitro (mini) tubers were induced within 6–8 weeks inserially propagated potato shoot cultures by subculturing tomedium containing 2.0 mg 1^–1 benzylaminopurine (BAP) and6 per cent sucrose in 8- and 24-h days. The effect of BAP inpromoting tubering was greater in short than in long days. Inshort days most of the tubers were formed above the agar, inlong days within the agar. Tubering was promoted less effectivelyby the addition of (2-chloroethyl)-trimethylammonium chloride(CCC) to the medium, but CCC reinforced the effect of BAP leadingto earlier tubering above the agar. Tubering eventually tookplace after 4—5 months on medium without hormones, soonerin short than in long days. Periods of short days and low temperaturesgiven to long-day cultures did not accelerate tubering. Abscisicacid had little effect on, and GA2 strongly inhibited, tubering.Tubering was also inhibited by sealing the culture vessels butnot if ethylene-absorbing agents were included. Solanum tuberosum L, potato, tissue culture, tubers, cytokinin, ethylene, daylength, propagation     

九种报春花属植物的核形态学研究

对报春花属（Prinula)4个组9种植物进行了核形态学研究。这9个种的间期核构形均为复杂染色中心型,前期染色体属于中间型,体细胞有丝分裂中期染色体的数目及核型如下：中甸海水仙报表P.monticola(Hand.-Mazz.)Chen et C.M.Hu,K(2n)=16=12m 4sm;高穗花报春P.vialii Delavay ex Franch.,K(2n)=20=16m 2sm 2st;偏花报春P.secundiflora Franch.,K(2n)=22=18m 4sm;海仙花报春P.poissonii Fanch.,K(2n)=22=16m 6sm;霞红灯台报春P.beesiana Forr.,K(2n)=22=18m 4sm;桔红灯台报春P.bulleyana Forr., K(2n)=22=18m 4sm;橙红灯台报春P.aurantiaca W.W.Smith et Forr.,K(2n)=22=16m(sat) 6sm;粉被灯台报春P.pulverulenta Duthie,K(2n)=22=19m 2sm 1st;钟花报春P.sikkimensis Hook.,K(2n)=20=14m(1sat) 4sm 2T。其中,中甸海水仙报春和高穗花报春两种的染色体数目及核型为首次报道。同时,本文还将偏花报春与灯台组报春以及钟花组报春进行了细胞学的比较分析。     

The Relation Between the Nitrogen Concentration and Photosynthetic Capacity of Potato (Solanum tuberosum L.) Leaves

Measurements of the rate of light-saturated photosynthesis (P_max)were made on terminal leaflets of potato plants growing in cropssupplied with 0, 3, 6, 12, 24 and 36 g N m^–2. Measurementswere made between 100 and 154 d after planting. Two types ofleaf were selected—the fourth leaf on the second-levelbranch (L₄, _B1) and the youngest terminal leaflet that was measurable(L_YM). Later, the total nitrogen concentration of each leaflet(N_L) was measured. A linear regression between P_max and N_L,common to both leaf positions, explained 68.5% of the totalvariation. With L₄, _B1 leaves there was a significant improvementin the proportion of variation explained when regressions withseparate intercepts and a common slope were fitted to individualfertilizer treatments. These results suggest that an increasingproportion of leaf nitrogen was not associated with the performanceof the photosynthetic system with increasing nitrogen supply.This separation between nitrogen treatments was not as clearfor L_YM leaves. Stomatal conductance to transfer of water vapourwas neither influenced by leaf position nor directly by nitrogensupply. Rather conductance declined in parallel with the declinein photosynthetic capacity. Solanum tuberosum, potato, nitrogen, photosynthesis, stomatal conductance, leaf     

In Vitro Fungicidal Photodynamic Effect of Hypericin on Trichophyton spp

Hypericin is a natural photosensitizer used in photodynamic therapy (PDT), which has shown in vitro antifungal effect against Candida spp. The aim of this study was to evaluate the in vitro fungicidal effect of hypericin-PDT on dermatophytes. Trichophyton rubrum and Trichophyton mentagrophytes strains were incubated with different concentrations of hypericin for different times and exposed to light-emitting diode lamp (602 ± 10 nm, 10.3 mW cm^?2, and fluence 37 J cm^?2). Using the optimal incubation time, 60 min, a 3-log fungicidal effect was achieved with hypericin concentration ranges of 10–20 μM for T. rubrum and 20–50 μM for T. mentagrophytes (p = 0.95). Confocal fluorescence microscopy showed the localization of hypericin inside the dermatophytes diffusely distributed in the cytoplasm of conidia and hyphae and outside the nucleus. In conclusion, hypericin-PDT has a fungicidal effect in vitro on dermatophytes. Hypericin seems to be a promising photosensitizer to treat localized dermatophytic infections such as tinea pedis and onychomycosis.     

Effect of Salt Stress on Growth,Na+ Accumulation and Proline Metabolism in Potato (Solanum tuberosum) Cultivars

Potato (Solanum tuberosum) is a major crop world-wide and the productivity of currently used cultivars is strongly reduced at high soil salt levels. We compared the response of six potato cultivars to increased root NaCl concentrations. Cuttings were grown hydroponically and treated with 0 mM, 60 mM and 180 mM NaCl for one week. Growth reduction on salt was strongest for the cultivars Mozart and Mona Lisa with a severe senescence response at 180 mM NaCl and Mozart barely survived the treatment. The cultivars Desiree and Russett Burbank were more tolerant showing no senescence after salt treatment. A clear difference in Na⁺ homeostasis was observed between sensitive and tolerant cultivars. The salt sensitive cultivar Mozart combined low Na⁺ levels in root and stem with the highest leaf Na⁺ concentration of all cultivars, resulting in a high Na⁺ shoot distribution index (SDI) for Mozart as compared to Desiree. Overall, a positive correlation between salt tolerance and stem Na⁺ accumulation was found and the SDI for Na⁺ points to a role of stem Na⁺ accumulation in tolerance. In stem tissue, Mozart accumulated more H₂O₂ and less proline compared to the tolerant cultivars. Analysis of the expression of proline biosynthesis genes in Mozart and Desiree showed a clear reduction in proline dehydrogenase (PDH) expression in both cultivars and an increase in pyrroline-5-carboxylate synthetase 1 (P5CS1) gene expression in Desiree, but not in Mozart. Taken together, current day commercial cultivars show promising differences in salt tolerance and the results suggest that mechanisms of tolerance reside in the capacity of Na⁺ accumulation in stem tissue, resulting in reduced Na⁺ transport to the leaves.