Inhibited Shoot Elongation Research Articles

Comparative analysis of physiological traits of three Actinidia valvata Dunn genotypes during waterlogging and post-waterlogging recovery

Kiwifruit (Actinidia sp.) vines are poorly adapted to waterlogging stress. Actinidia valvata is more tolerant against waterlogging stress than Actinidia deliciosa, and the latter contains some common rootstocks that are frequently used in kiwifruit cultivation. Little is known about the responses of A. valvata genotypes against waterlogging stress and during post-waterlogging recovery. Here, we compared physiological traits of three A. valvata genotypes (KR1, KR3, and KR5) during waterlogging stress and recovery. Kiwifruit vines displayed water loss, a decline in the net photosynthetic rate, and inhibited shoot elongation during waterlogging. These three genotypes could endure long-term waterlogging owing to their unique root system configurations as well as by sustaining carbohydrate reserves in the roots. Feeder roots of KR1 vines were damaged earlier and lost water more quickly than the other genotypes. Under the same stress, KR3 formed adventitious roots more rapidly, while KR5 had an improved ability to control water loss in above-ground tissues. After reoxygenation, growth of vines was partially recovered due to water loss control, photosynthetic recovery, and carbohydrate replenishment. KR3 and KR5 recovered their growth earlier and replenished more carbohydrates than KR1 after re-aeration. During waterlogging, both the relative water content and carbohydrate levels of vines can limit the recovery efficiency after re-aeration. Our results revealed mutual and distinct responses of different A. valvata genotypes during waterlogging stress and recovery and provided more insight into the physiological basis of their adaptation to waterlogging stress.

The potential of the iron concentrated germinated wheat in wheat flour fortification: an alternative to the conventional expensive iron fortification.

Investigation of the effect of the Fe abiotic stress on the germination rate, iron accumulation, root and shoot elongation of wheat (Triticum aestivum) was carried out. The grains were exposed to different experimental concentrations of ferrous sulfate (FeSO4) (0-15mM). The effect of the treatment on the shoot and root elongation of the seeds were reported. There is a linear relationship between the treatment and the inhibition of shoot elongation. The half-inhibition dose (ID50) of FeSO4 on inhibition of shoot elongation was 7.3mM. Each treatment groups (3-15mM) were used to fortify the wheat flour at 0.1mg Fe/g. The effect of fortification on rheology (farinograph, extensograph, and amylograph), quality of pasta and iron bioavailability was studied. The pasta cooking properties, texture and sensory properties of 12 and 15mM composite pasta were equally acceptable as wheat without fortification, or NaFeEDTA fortified pasta. The iron dialysability of 3-15mM composite pasta was similar to the NaFeEDTA fortified pasta. The iron bioavailability (in vivo) of 15mM group based pasta was evaluated in the anemic rats. The pasta at 4% (Fe 0.026mg/g) in iron-deficient diet fed to anemic rats for 2weeks showed percentage iron absorption (PIA) and hemoglobin regeneration efficiency (HRE) of 85.3% and 44.4% respectively which is higher than the NaFeEDTA. In conclusion, iron-fortified pasta is the promising food fortificant with more iron bioavailability in the prevention of iron deficiency anemia.

A transcriptome analysis of two apple (Malus × domestica) cultivars with different flowering abilities reveals a gene network module associated with floral transitions

Young ‘Nagafu No. 2′ apple trees produce fewer flower buds than the trees of other apple cultivars, including ‘Yanfu No. 6′ (i.e., ‘Fuji’ apple tree exhibiting a bud mutation). Thus, we analyzed the flowering characteristics of these two varieties to further characterize apple floral transition. RNA sequencing was used to characterize differentially expressed genes in buds between the two cultivars during floral transition. Differences in several physiological parameters were also analysed. A total of 3,010, 1,139, and 1346 differentially expressed genes were identified at 30, 50, and 70 days after full bloom. These genes combined with the differences in physiological indices indicated that low gibberellic acid levels and high cytokinin levels in ‘Yanfu No. 6′ buds during the floral induction stage increased the production of flower buds. High cytokinin levels inhibited gibberellic acid signaling and promoted floral transition. Additionally, low gibberellic acid levels likely inhibited shoot elongation by impairing DELLA degradation. Meanwhile, relatively high indole-3-acetic acid and cytokinin levels synergistically maintained meristem activities and accelerated bud growth. Moreover, the high sucrose content in ‘Yanfu No. 6′ buds up-regulated the transcription of TREHALOSE 6-PHOSPHATE SYNTHASE and SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE genes, which ultimately promoted floral induction. The data presented herein indicate that floral transition differences between the two analyzed apple cultivars are linked to sugar and cytokinin signaling pathways.

Leaf gas films, underwater photosynthesis and plant species distributions in a flood gradient.

Traits for survival during flooding of terrestrial plants include stimulation or inhibition of shoot elongation, aerenchyma formation and efficient gas exchange. Leaf gas films form on superhydrophobic cuticles during submergence and enhance underwater gas exchange. The main hypothesis tested was that the presence of leaf gas films influences the distribution of plant species along a natural flood gradient. We conducted laboratory experiments and field observations on species distributed along a natural flood gradient. We measured presence or absence of leaf gas films and specific leaf area of 95 species. We also measured, gas film retention time during submergence and underwater net photosynthesis and dark respiration of 25 target species. The presence of a leaf gas film was inversely correlated to flood frequency and duration and reached a maximum value of 80% of the species in the rarely flooded locations. This relationship was primarily driven by grasses that all, independently of their field location along the flood gradient, possess gas films when submerged. Although the present study and earlier experiments have shown that leaf gas films enhance gas exchange of submerged plants, the ability of species to form leaf gas films did not show the hypothesized relationship with species composition along the flood gradient.

Antagonistic action of blue and red light on shoot elongation in petunia depends on gibberellin, but the effects on flowering are not generally linked to gibberellin

Plant morphology and flowering are influenced by light quality, but responses vary between species. Here we investigated effects of irradiance (70 or 150μmolm−2s−1) of red (R) and blue (B) compared to white (W) light, provided by light emitting diodes, on growth and flowering in petunia. R light inhibited shoot elongation, but opposite to commonly observed, B light greatly enhanced shoot elongation. Consistent with this, bioactive gibberellins (GA1, GA4) showed higher and lower levels under B and R light, respectively, and GA3 application induced elongation in uniconazole-treated plants, although delayed in R. Inhibited shoot elongation under RB treatment in spite of higher GA level compared to R only, supports that R light inhibits elongation growth, and indicates negative effect of R light on GA signaling. Floral bud formation and flowering occurred earlier under B compared to W light. Whereas no floral buds were observed under low R irradiance, high R irradiance and temporal switching to B light during long-term low R irradiance induced floral development. Except slight trends of promoting effect of the highest GA3 level and delay in uniconazole-response under B light, lack of flowering under low R irradiance was not significantly affected by uniconazole or GA3 application. In conclusion, B and R light are strong signals enhancing and inhibiting shoot elongation, respectively, through modulation of GA content. B light is a strong signal in floral bud formation, whereas effect of R light depends on irradiance, indicating existence of an energy/photosynthesis-related floral pathway in petunia. Although light quality affects flowering and main shoot elongation, these responses do probably not correlate with each other through GA synthesis.

Physiological and Antioxidant Responses of Germinating Mung Bean Seedlings to Phthalate Esters in Soil

Single phytotoxicity of two representative phthalate esters (PAEs), di-n-butyl phthalate (DnBP) and bis(2-ethylhexyl) phthalate (DEHP), was tested in mung bean (Vigna radiata) seedlings germinated for 72 h in soils spiked with varying concentrations (0-500 mg kg−1 soil) of DnBP or DEHP. PAEs added at up to 500 mg kg−1 soil exerted no significant effect on germination but both pollutants significantly inhibited root elongation (P < 0.01), DEHP inhibited shoot elongation (P < 0.01) and DnBP depressed biomass on a fresh weight basis (P < 0.05). Seedling shoot and root malondialdehyde (MDA) contents tended to be stimulated by DnBP but inhibited by DEHP. However, increases in superoxide dismutase, peroxidase, ascorbate peroxidase and polyphenol oxidase activities, as well as glutathione (GSH) content, were induced at higher concentrations (e.g., 20 mg kg−1) of both compounds. Accumulation of proline in both roots and shoots and the storage compounds, such as free amino acids and total soluble sugars, in whole plant was induced under the stress exerted by both PAEs. The general responses of mung bean seedlings indicated higher toxicity of DnBP than DEHP on primary growth, during which root elongation was a more responsive index. MDA and GSH were more sensitive parameters in the roots than in the shoots and they might be recommended as physiologically sensitive parameters to assess the toxicity of PAE compounds in soils in future long-term studies.

1-Methylcyclopropene prevents cotton physiological and molecular responses to ethylene

The phytohormone ethylene can cause adverse effects in plants, including inhibition of shoot elongation and abscission of leaves, flowers and fruits. 1-Methylcyclopropene (1-MCP) is a competitive inhibitor of ethylene binding with the ethylene receptors and prevents ethylene responses. To determine the effectiveness of 1-MCP as an ethylene prophylactic for cotton, an assay system was developed that integrated analyses of leaf declination, shoot elongation and ethylene-responsive gene expression (GhACS6, GhACO5, GhEIN4, GhLTL1). Using a flow-through controlled growth system, the optimal parameters of ethylene treatment in eliciting responses and of 1-MCP treatment in preventing these responses, were determined. Shoot elongation and gene expression changes in response to ethylene correlated well, but gene expression changes were found to offer a more robust estimate of ethylene responsiveness. The effect of ethylene treatment on the expression of the marker genes was determined to be optimal with 3 h of 10 μL L−1 fumigation. 250 nL L−1 of gaseous 1-MCP provided for 1 h immediately before ethylene fumigation was highly efficacious at preventing ethylene responses, but the duration of protection did not exceed 48 h. A liquid formulation of 1-MCP designed for field use was found to be equally effective as the gas. The results, and the system described, may prove useful in increasing 1-MCP efficacy as a tool to manage the negative effects of stress ethylene in cotton crops.

CHARACTERISTICS OF LINGONBERRY PLANTS PROPAGATED BY IN VITRO AND EX VITRO PROPAGATION METHODS

ISHS XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Berries: From Genomics to Sustainable Production, Quality and Health CHARACTERISTICS OF LINGONBERRY PLANTS PROPAGATED BY IN VITRO AND EX VITRO PROPAGATION METHODS

An efficient protocol for regeneration and transformation of Symphyotrichum novi-belgii

A protocol for adventitious shoot formation in Symphyotrichum novi-belgii was developed after investigating the effects of cultivar and hormone combinations. A Murashige and Skoog medium with 1.0 mg l−1 6-benzyladenine induced adventitious shoot formation in 15 out of 19 cultivars. Addition of 0.1 mg l−1 indole-3-acetic acid or naphthaleneacetic acid increased the total number of shoots per explant, but not the number of shoots longer than 1 cm. Addition of dichlorophenoxyacetic acid (2,4-D) promoted callus formation, but inhibited shoot elongation. A transformation system for the two cultivars Victoria Fanny and Victoria Jane was developed by co-cultivation of leaf explants with Agrobacterium tumefaciens. Three bacterial strains (LBA 4404, A281 and C58) all carrying the binary vector, p35S-GUS-INT, and harbouring the uidA gene coding for β-glucuronidase (GUS) were used. Regeneration of transgenic plants after co-cultivation with A281 was independent of cultivar, and all explants produced callus followed by indirect shoot formation. In ‘Victoria Fanny’ shoots were formed faster and without a callus phase after co-cultivation with LBA 4404 or C58. The highest number of potentially transformed shoots was regenerated after co-cultivation of ‘Victoria Fanny’ leaf explants with LBA 4404. Integration of the transgenes in the plant genome was confirmed using PCR and Southern blot hybridisation. To verify that the transgenes could be transferred to offspring, crosses were conducted between three transgenic lines of ‘Victoria Fanny’ and two wild type pollen donors. It was demonstrated that viable seeds were produced and that the uidA gene was inherited.

Micropropagation of Embelia ribes Burm f. through proliferation of adult plant axillary shoots

Micropropagation of Embelia ribes was achieved through proliferation of axillary shoots obtained from mature plants. Nodal shoot segments, collected March–May, exhibited high-frequency (75%) shoot initiation when cultured on Murashige and Skoog (MS) basal medium supplemented with thidiazuron (TDZ) at 1.13 µM and indole-3-butyric acid (IBA) at 0.49 µM. Subculture of sprouted shoots from the original explants on medium containing TDZ (1.13 and 0.45 µM) during the first and second subcultures was found essential for further shoot proliferation, while inhibition of shoot elongation by TDZ could be overcome by transferring shoot cultures onto MS medium containing 6-benzylaminopurine (BAP; 11.10 µM) for the third subculture. Treating the explants with an antioxidant mixture of 568 µM ascorbic acid, 119 µM citric acid, and 307 µM glutathione prior to inoculation, coupled with subculture at 2-wk intervals onto fresh medium, both helped to reduce browning of the explants and facilitated production of five to six shoots/explant. MS medium supplemented with BAP (4.44 µM) and IBA (0.49 µM) induced shoot multiplication, producing five to six shoots/explant with a shoot length of 3 to 4 cm over a 4-wk culture period. Shoots of 3 to 4 cm in length exhibited 100% rooting within 4 wk after transfer to media containing half the nutrient salt concentration of MS medium with 3.69 µM IBA. Ex vitro rooting in the greenhouse from the in vitro shoots treated with 4.93 µM IBA for 30 min exhibited 95% rooting in soilrite™ medium in a 4-wk period. About 85% of micropropagated plants were established successfully in root trainers. Three-month-old, hardened plants could further be successfully established in the field. In 1 yr, by using the above protocol, 3,200 plants could be produced from a single shoot and 2,700 could be established in the field.

Light and temperature sensing and signaling in induction of bud dormancy in woody plants

In woody species cycling between growth and dormancy must be precisely synchronized with the seasonal climatic variations. Cessation of apical growth, resulting from exposure to short photoperiod (SD) and altered light quality, is gating the chain of events resulting in bud dormancy and cold hardiness. The relative importance of these light parameters, sensed by phytochromes and possibly a blue light receptor, varies with latitude. Early in SD, changes in expression of light signaling components dominate. In Populus active shoot elongation is linked to high expression of FLOWERING LOCUS T (FT) resulting from coincidence of high levels of CONSTANS and light at the end of days longer than a critical one. In Picea, PaFT4 expression increases substantially in response to SD. Thus, in contrast to Populus-FT, PaFT4 appears to function in inhibition of shoot elongation or promotion of growth cessation. Accordingly, different FT-genes appear to have opposite effects in photoperiodic control of shoot elongation. Reduction in gibberellin under SD is involved in control of growth cessation and bud formation, but not further dormancy development. Coinciding with formation of a closed bud, abscisic acid activity increases and cell-proliferation genes are down-regulated. When dormancy is established very few changes in gene expression occur. Thus, maintenance of dormancy is not dependent on comprehensive transcriptional regulation. In some species low temperature induces growth cessation and dormancy, in others temperature affects photoperiod requirement. The temperature under SD affects both the rate of growth cessation, bud formation and depth of dormancy. As yet, information on the molecular basis of these responses to temperature is scarce.

Comparison of shoot induction ability of different explants in herbaceous peony ( Paeonia lactiflora Pall.)

Shoot induction ability of explants of herbaceous peony was investigated in semisolid MS medium containing BA, TDZ and GA 3. Callus was readily induced from stem without node and petiole explants within 2 days of culture but failed to generate shoots. Adventitious shoots were successfully produced from meristematic regions only: bud eyes on nodal stem sections, and junctions of petioles and petiolules. No shoots were induced from internode sections, petiole without junctions, or leaf sections. Nodal sections were the most efficient explants. There were up to 20 shoots in one explant generated within 20 days of culture. TDZ was more effective than BA to induce shoots. The 100% shoot induction rate was obtained in medium containing 0.1–3 mg L −1 of TDZ. However, higher concentrations of TDZ inhibited shoot elongation and only large leaf clusters were produced. Combinations of BA and TDZ failed to increase shoot induction rates but caused shoots shorter. The 2–60-min pretreatment of explants with 20 mg L −1 TDZ solution was very effective to induce adventitious shoots directly, but both shoot number and shoot length tended to decrease as treatment time increased. GA 3 was beneficial for shoot and stem elongation.

Growth-active gibberellins overcome the very slow shoot growth of Hancornia speciosa, an important fruit tree from the Brazilian “Cerrado”

Shoot elongation of Hancornia speciosa, an endangered tree from the Brazilian savannah “Cerrado”, is very slow, thus limiting nursery production of plants. Gibberellins (GAs) A1, A3, and A5, and two inhibitors of GA biosynthesis, trinexapac-ethyl and ancymidol were applied to shoots of Hancornia seedlings. GA1 and GA3 significantly stimulated shoot elongation, while GA5 had no significant effect. Trinexapac-ethyl and ancymidol, both at 100 µg per seedling, inhibited shoot elongation up to 45 days after treatment, though the effect was statistically significant only for ancymidol. Somewhat surprisingly, exogenous GA3 more effectively stimulated shoot elongation in SD-grown plants, than in LD-grown plants. The results from exogenous application of GAs and inhibitors of GA biosynthesis imply that Hancornia shoot growth is controlled by GAs, and that level of endogenous growth-active GAs is likely to be the limiting factor for shoot elongation in Hancornia. Application of GAs thus offer a practical method for nursery production of Hancornia seedlings for outplanting into the field.

Zeatin and TDZ-induced Shoot Proliferation and Use of Bioreactor in Clonal Propagation of Medicinal Herb, Roseroot (Rhodiola rosea L)

A procedure for in vitro propagation of roseroots (Rhodiola rosea L), a medicinal plant, was developed using a RITA bioreactor system containing liquid medium, combined with a gelled medium. Wild roseroot clones: ‘RCi’, ‘RC2’ and ‘RC3’ were established on a basal medium (BM) from in vitro-germinated seedlings on half-strength Murashige and Skoog (MS) salts. TDZ at 2–4 μM supported shoot proliferation but inhibited shoot elongation of ‘RCi’ shoots on gelled medium. Clones differed significantly with respect to multiplication rate with ‘RCi’ producing the most shoots per explant on gelled BM with 2 μM zeatin. In a bioreactor system, TDZ supported rapid shoot proliferation at lower concentration (0.5 μM) but induced hyperhydricity at more than 0.5 μM. Bioreactor-multiplied hyperhydric shoots of all clones when transferred to gelled medium containing 1–2 μM zeatin produced normal shoots within 4 wk of culture. Shoots were rooted in vitro on BM void of growth regulators. Almost all (9U to 95%) in vitro plantlets survived when transferred to potting medium.

Characteristics of strawberry plants propagated by in vitro bioreactor culture and ex vitro propagation method

AbstractReproducible protocol for regeneration of complete plantlets from ‘Bounty’ strawberry (Fragaria ananassa Duch.), using a combination of gelled medium and bioreactor system, has been standardized. Sepals, leaf discs, and petiole halves produced multiple buds and shoots when cultured on semi solid‐gelled medium containing 4 μM thidiazuron (TDZ) for 4 wk followed by transferring in liquid medium containing 2 μM TDZ in a bioreactor system and cultured for another 4 wk. TDZ induced shoot proliferation at 0.1 μM in the bioreactor system but inhibited shoot elongation. TDZ‐induced shoots were elongated and rooted in vitro on gelled medium containing 2 μM zeatin. Such bioreactor‐derived tissue culture (BC) plantlets obtained from sepal explants were grown ex vitro and compared with those propagated by tissue culture on gelled medium (GC) and by conventional runner cuttings (RC), for growth, morphology, anthocyanin content, and antioxidant activity after three growth seasons. The BC and GC plants produced more crowns, runners, leaves, and berries than the RC plants although berry weight per plant did not differ significantly. BC and GC plants produced berries with more anthocyanin contents and antioxidant activities than those produced by the RC plants. However, intersimple sequence repeat (ISSR) marker assay produced a homogenous amplification profile in the tissue culture and donor control plants confirming the clonal fidelity of micropropagated plants. In vitro culture on TDZ and zeatin‐containing nutrient media apparently induced the juvenile branching characteristics that favored enhanced vegetative growth with more crown, runners, leaf, and berry production.

Modification of Cell Wall Architecture in Gramineous Plants under Altered Gravity Conditions

Gramineous plants, such as rice, wheat, and maize, are essential crops. The cell wall composition of gramineous plants is distinguished from that of dicotyledons, such as Arabidopsis, pea, and mung bean. In cell walls of gramineous plants, arabinoxylans and β-glucans are the major matrix polysaccharides and they make network structure within cell wall architecture. Gravitational stimuli affect the metabolism of β-glucans in gramineous shoots; hypergravity suppressed the β-glucan breakdown, when it inhibited shoot elongation. The opposite results were obtained under microgravity conditions in space. On the other hand, the arabinoxylan and diferulic acid (DFA) contents increased under continuous hypergravity conditions. Since arabinoxylans are cross-linked by DFA-bridges, continuous hypergravity may stimulate the formation of arabinoxylan-DFA network within cell walls. These findings suggest that the β-glucan metabolism is primarily involved in the mechanism of growth regulation, while the arabinoxylan-DFA network has a load-bearing function against the gravitational force. The modification of these wall constituents may contribute to the capacity of gramineous plants to sustain their structure and growth under altered gravity conditions.

Prohexadione-Ca Affects Vegetative Growth of the Rejuvenated Shoots in Walnut Trees

Prohexadione-calcium (ProCa), formulated as Regalis, was tested as a vegetative growth inhibitor in rejuvenated annual shoots of 14-year-old mother trees in the ‘Franquette’ walnut cultivar. ProCa was applied three times during growing seasons in 2005 (Y5) and 2006 (Y6). This was during the second half of spring growth flush, the resting phase between the first and second growth flushes, and in the middle of summer growth flush. As a result, treated shoots in the upper part of the canopy were shorter than untreated ones during the whole growing season in both years. In Y5, two treatments of ProCa (250 mg·L−1), applied until the middle of June, inhibited shoot elongation during summer growth, which was the main purpose of the experiment. The reduction of shoot elongation was between 18% [lower shoots in the canopy (LS)] and 33% [upper shoots (US)]. After three ProCa applications, also the final length of the shoots was reduced by 5% (US) and 18% (LS). In Y6, when 100 mg·L−1 of ProCa had been used, strong reduction (24%) was observed only in US after two treatments. Summer growth was not reduced, probably as a result of an interaction between lower concentration of ProCa and stress caused by a water deficit and extremely high temperatures during the summer. On the base of the shoots, three treatments of ProCa (100 mg·L−1) in Y6 increased the ratio between wood and pith and, consequently, increased the quality and uniformity of the scion wood. Further research into additional cultivars and ProCa concentrations is recommended to optimize the terms of application.

Growth Responses of Seedlings in Oryza glaberrima Steud. to Short-term Submergence in Guinea, West Africa

In inundation areas in rainfed lowland and inland valleys of Guinea as well as other regions in Africa, submergence for a few days to a few weeks with a water depth less than 50 cm occurs in rice cultivation during the rainy season. Young rice seedlings after transplanting are particularly vulnerable to submergence stress. Oryza glaberrima Steud. is well adapted to growth in inundation areas with deepwater conditions in West Africa; however, it is not evident whether it resists short-term submergence stress after transplanting. The purpose of the study was to understand the physiological responses of rice plants after transplanting to short-term submergence stress under rainfed conditions for O. glaberrima by comparison with several genotypes of Oryza sativa L. from Guinea. Eight genotypes of O. glaber­ rima and seven genotypes of O. sativa including two shoot elongation genotypes, one submergence tolerant genotype as a control cultivars, and four genotypes of common cultivars in West Africa were used. Thirty day-old seedlings were submerged completely for 10 days with medium deepwater conditions at 45 cm water depth at 13 days after transplanting in a lowland field. O. glaberrima showed higher shoot elongation ability during submergence than any genotype of O. sativa that we tested. However, O. gla­ berrima lodged easily after desubmergence due to longer and rapid shoot elongation during submergence, and thus triggered a decrease in its survival rate. The submergence tolerant genotype of O. sativa maintained the dry matter weight of the leaf blade during submergence through the inhibition of shoot elongation. We suggest that O. glaberrima is susceptible to short-term submergence while it may adapt to prolonged flooding because of improved restoration of aerial photosynthesis and survival rate through shoot elongation ability.

Proteomic analysis reveals differences between Vitis vinifera L. cv. Chardonnay and cv. Cabernet Sauvignon and their responses to water deficit and salinity

The impact of water deficit and salt stress on two important wine grape cultivars, Chardonnay and Cabernet Sauvignon, was investigated. Plants were exposed to increasing salinity and water deficit stress over a 16 d time period. Measurements of stem water potentials, and shoot and leaf lengths indicated that Chardonnay was more tolerant to these stresses than Cabernet Sauvignon. Shoot tips were harvested every 8 d for proteomic analysis using a trichloroacetic acid/acetone extraction protocol and two-dimensional gel electrophoresis. Proteins were stained with Coomassie Brilliant Blue, quantified, and then 191 unique proteins were identified using matrix-assisted laser desorption ionization time of flight/time of flight mass spectrometry. Peptide sequences were matched against both the NCBI nr and TIGR Vitis expressed sequence tag (EST) databases that had been implemented with all public Vitis sequences. Approximately 44% of the protein isoforms could be identified. Analysis of variance indicated that varietal difference was the main source of protein expression variation (40%). In stressed plants, reduction of the amount of proteins involved with photosynthesis, protein synthesis, and protein destination was correlated with the inhibition of shoot elongation. Many of the proteins up-regulated in Chardonnay were of unclassified or of unknown function, whereas proteins specifically up-regulated in Cabernet Sauvignon were involved in protein metabolism.

In vitro propagation of Indian Kino (Pterocarpus marsupium Roxb.) using Thidiazuron

An efficient protocol was developed for micropropagation of an economically important timber-yielding multipurpose tree, Pterocarpus marsupium Roxb. Multiple shoots were induced from cotyledonary nodes (CNs) derived from 18-d-old axenic seedlings on Murashige and Skoog (MS) medium supplemented with thidiazuron (TDZ) (0.1–10 μM). The highest shoot regeneration frequency (90%) and maximum number (15.2 ± 0.20) of shoots per explant was recorded on MS medium amended with 0.4 μM TDZ. Continuous presence of TDZ inhibited shoot elongation. In the primary medium, TDZ-initiated cultures were transferred to the secondary medium supplemented with another cytokinin, 6-benzyladenine (BA), for shoot growth and elongation. Maximum (90%) shoot elongation with an average shoot length of 5.4 ± 0.06 cm was observed at 5 μM BA. To further enhance the number of shoots per explant, mother tissue was repeatedly subcultured on fresh shoot induction medium after each harvest of newly formed shoots. Thus, by adopting this strategy, an average of 44 shoots per explant could be obtained. About 65% of in vitro regenerated shoots produced a maximum number (4.4 ± 0.2) of roots per shoot by a two-step culture procedure employing pulse treatment and subsequent transfer of treated shoots to a low concentration of 0.2 μM indole-3-butyric acid along with phloroglucinol (3.96 μM). The in vitro-raised plantlets were successfully acclimatized first under culture room conditions, then to greenhouse with 70% survival rate.