biologia plantarum

International journal on Plant Life established by Bohumil Nìmec in 1959

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Results 1081 to 1110 of 6170:

Romano, A. (ed.): Proceedings of the Third International Symposium on Acclimatization and Establishment of Micropropagated Plants (Acta Horticulturae 812)

J. Pospí¹ilová

Biologia plantarum 53:400, 2009 | DOI: 10.1007/s10535-009-0077-0

Understanding Bioinformatics

R. Podlipná

Biologia plantarum 53:522, 2009 | DOI: 10.1007/s10535-009-0094-z

Biologia Plantarum founded 50 years ago

J. Krekule

Biologia plantarum 53:601-602, 2009 | DOI: 10.1007/s10535-009-0110-3

Chitinases of Coffea arabica genotypes resistant to orange rust Hemileia vastatrix

L. Guerra-Guimarães, M. C. Silva, C. Struck, A. Loureiro, M. Nicole, C. J. Rodrigues Jr., C. P. P. Ricardo

Biologia plantarum 53:702-706, 2009 | DOI: 10.1007/s10535-009-0126-8

Two Coffea arabica - Hemileia vastatrix incompatible interactions (I1: coffee cv. Caturra - rust race VI and I2: coffee cv S4 Agaro - rust race II) and a compatible interaction (coffee cv. Caturra - rust race II) were compared in relation to the infection process and chitinase activity. In the two incompatible interactions the fungus ceased growth in the early infection stages, while in the compatible interaction no fungus growth inhibition was observed. A high constitutive level of chitinase activity was detected in the intercellular fluid of healthy leaves. Upon infection, chitinase isoforms were more abundant in incompatible interactions than in the compatible interaction. Immunodetection showed that class I chitinases are particularly relevant in the incompatible interactions and might participate in the defence response of the coffee plants.

Micropropagation and conservation of endangered species Plantago algarbiensis and P. almogravensis

S. Gonçalves, N. Martins, A. Romano

Biologia plantarum 53:774-778, 2009 | DOI: 10.1007/s10535-009-0142-8

Plantago algarbiensis and P. almogravensis are endemic Al tolerant species from the Western-centre of the Algarve region (South of Portugal) and Portuguese Southwest coast, respectively, which are in risk of global extinction. The aim of this work was to establish an efficient protocol to in vitro propagate these species using shoots obtained from in vitro germinated seeds. The best results in terms of multiplication response were afforded in Murashige and Skoog's (MS) medium supplemented with 6-benzyladenine (8.5 and 9.2 shoots per explant in P. algarbiensis and P. almogravensis, respectively). Shoots of both species showed a great rooting capacity (100 and 80 % for P. algarbiensis and P. almogravensis, respectively) that was not significantly influenced by the concentration of MS macronutrients or auxins. Plants were acclimatized to ex vitro conditions, exhibited normal development (survival rate of 95 and 80 % in P. algarbiensis and P. almogravensis, respectively), and were successfully reintroduced in their natural habitat.

Involvement of phospholipase C-independent calcium-mediated abscisic acid signalling during Arabidopsis response to drought

A. Cousson

Biologia plantarum 53:53-62, 2009 | DOI: 10.1007/s10535-009-0008-0

The present study investigated whether Ca2+ mobilization independent of phosphoinositide-specific phospholipase C (PI-PLC) would delay wilting in Arabidopsis thaliana (L.) Heynh. cv. Columbia through mediating stomatal closure at abscisic acid (ABA) concentrations rising beyond a drought-specific threshold value. In wild type (WT) epidermis, the PI-PLC inhibitor (U73122) affected the stomatal response to 20 µM ABA but not to 30 µM ABA. Disruption in GTP-binding protein ά subunit 1 (GPA1) affected the stomatal response to 30 µM ABA, but not to 20 µM ABA. In the gpa1-4 mutant, the inhibitory effects of the Ca2+ buffer, 1,2-bis(0-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), the inactive mastoparan analogue, mas17 and the antagonist of cyclic ADP-ribose synthesis, nicotinamide, were differentially attenuated on 30 µM ABA-induced stomatal closure. By contrast, the NADPH oxidase atrbohD/F double mutation fully suppressed inhibition of 20 µM ABA-induced stomatal closure by BAPTA or U73122 as well as inhibition of 30 µM ABA-induced stomatal closure by BAPTA, mas17 or nicotinamide. On the contrary, The Al resistant alr-104 mutation modulated ABA-induced stomatal closure by a stimulatory effect of U73122 and an increased sensitivity to mas17, nicotinamide and BAPTA. Compared to WT, the atrbohD/F double mutant was more hypersensitive than the gpa1-4 mutant to wilting under the tested water stress conditions, whereas wilting was delayed in the alr-104 mutant. Since the atrbohD/F mutation breaks down ABA-induced Ca2+ signalling through fully preventing apoplastic Ca2+ to enter into the guard cells, these results showed that a putative guard cell GPA1-dependent ADP-ribosyl cyclase activity should contribute to drought tolerance within PI-PLC-independent-Ca2+-mediated ABA signalling.

Stomatal and non-stomatal limitations to photosynthesis in field-grown grapevine cultivars

D. J. Yu, S. J. Kim, H. J. Lee

Biologia plantarum 53:133-137, 2009 | DOI: 10.1007/s10535-009-0019-x

Diurnal changes of photosynthesis in the leaves of grapevine (Vitis vinifera × V. labrusca) cultivars Campbell Early and Kyoho grown in the field were compared with respect to gas exchanges and actual quantum yield of photosystem 2 (ΦPS2) in late May. Net photosynthetic rate (PN) of the two cultivars rapidly increased in the morning, saturated at photosynthetic photon flux density (PPFD) from 1200 to 1500 µmol m-2 s-1 between 10:00 and 12:00 and slowly decreased after midday. Maximum PN was 13.7 and 12.5 µmol m-2 s-1 in Campbell Early and Kyoho, respectively. The stomatal conductance (gs) and transpiration rate changed in parallel with PN, indicating that PN was greatly affected by gs. However, the decrease in PN after midday under saturating PPFD was also associated with the observed depression of ΦPS2 at high PPFD. The substantial increase in the leaf to air vapour pressure deficit after midday might also contribute to decline of gs and PN.

Agrobacterium-mediated genetic transformation of plants: The role of host

O. Karami, M. Esna-Ashari, G. Karimi Kurdistani, B. Aghavaisi

Biologia plantarum 53:201-212, 2009 | DOI: 10.1007/s10535-009-0041-z

Agrobacterium-mediated genetic transformation is the most widely used technology to obtain overexpression of recombinant proteins in plants. Molecular events that occur within Agrobacterium during interactions with host plants have been studied extensively, and now we have a reasonable understanding the key factors involved in the regulation of T-DNA nuclear import and genomic integration. By contrast, very little is known about the events that take place in the host cells during genetic transformation by Agrobacterium. Here, we describe the plant-related factors including genotype, genes, proteins, competency of target tissues and phenolic compounds that participate in Agrobacterium-mediated genetic transformation and discuss their possible roles in this process. Because Agrobacterium probably adapts existing cellular processes for its life cycle, identifying the processes in host cells during Agrobacterium infection might contribute to better understanding of basic biological processes as cell communication, intracellular transport and DNA repair and recombination as well as to expanding the host range of Agrobacterium as a genetic engineering tool.

Genetic variability in the endemic Leucojum valentinum

A. Jordán-Pla, E. Estrelles, M. Boscaiu, P. Soriano, O. Vicente, I. Mateu-Andrés

Biologia plantarum 53:317-320, 2009 | DOI: 10.1007/s10535-009-0057-4

The genetic variability of Leucojum valentinum Pau (Amaryllidaceae), a vulnerable endemic species restricted to a small area in the region of Valencia (Eastern Spain), has been studied using random amplified polymorphic DNA (RAPD) markers. A total of 197 individuals from eleven populations were studied using 13 RAPD primers. Our results show high variability for the species, low differentiation among populations and uncorrelated levels of genetic variability and population size. Four groups in which three populations (SAG, PUG and COL) are separated from all the others were found, but without connection to geographical location.

Somatic embryogenesis and plant regeneration in Cedrela fissilis

S. Vila, A. Gonzalez, H. Rey, L. Mroginski

Biologia plantarum 53:383-386, 2009 | DOI: 10.1007/s10535-009-0072-5

Somatic embryos were obtained from immature zygotic embryos of Cedrela fissilis Well. (Meliaceae), after a culture period of 12 months, with regular subcultures every 6-8 weeks. Callus was developed on explants in 2 months on Murashige and Skoog (MS) medium containing 2,4 dichlorophenoxyacetic acid (2,4-D) or picloram (PIC). When the calli were transferred to fresh medium, embryogenic tissue appeared on MS + 45 µM 2,4-D, or 22.5 µM 2,4-D + 0.4 µM 6-benzyladenine (BA), or 20.7 µM PIC after 6 months. Sub-culture of embryogenic tissue in MS medium supplemented with 4.5 µM 2,4-D resulted in the differentiation into somatic embryos after further 4 months. Repeated secondary somatic embryogenesis was achieved by regular subculture on this medium. Maturation and conversion of somatic embryos into plantlets was achieved on MS medium without plant growth regulators and the conversion frequency was approximately 12.5 %. The plantlets were successfully acclimatized in pots with soil. Histological studies showed that somatic embryos had no detectable connection with the mother explants and that somatic embryos in advanced stages were bipolar with shoot and root apical meristems, they contained vascular system and showed typical characteristics of a somatic dicotyledonous embryo.

Regulation of the ALBINO3-mediated transition to flowering in Arabidopsis depends on the expression of CO and GA1

A. X. Wang, D. Y. Wang

Biologia plantarum 53:484-492, 2009 | DOI: 10.1007/s10535-009-0089-9

ALBINO3, a homologue of PPF1 in Arabidopsis, encodes a chloroplast protein, and is essential for chloroplast differentiation. In the present study, ALBINO3(-) transgenic plants exhibited a significant decrease in both the number of rosette leaves at bolting and the days before bolting, suggesting the important roles of ALBINO3 in regulating flowering during non-inductive short-day photoperiods. ALBINO3 mRNA was apparently accumulated in shoot apical meristem and floral meristems around the shoot apical meristem in wild-type plants. ALBINO3 might be predominantly involved in inducing the floral repression pathway by activating the expression of TFL1, and by suppressing the expression of LFY, respectively, in the shoot apical meristem. Moreover, the function of ALBINO3 in regulating flowering transition depended on the expression of CO and GA1, because ALBINO3 might function in the downstream integration of the photoperiod-dependent and the photoperiod-independent pathways. These results suggest that ALBINO3 may have an important integrative function in the flowering process in Arabidopsis.

Regeneration of transgenic citrus plants from the trimmed shoot/root region of etiolated seedlings

D. L. Li, B. Tan, Y. X. Duan, W. W. Guo

Biologia plantarum 53:578-582, 2009 | DOI: 10.1007/s10535-009-0105-0

Transformation and high efficient regeneration of transgenic plants from the trimmed etiolated shoot/root region (TESRR) of Anliucheng sweet orange [Citrus sinensis (L.) Osb.] seedling was reported. A visual green fluorescent protein (GFP) marker gene was introduced to evaluate transformation efficiency by using the explants from TESRR and epicotyls. The transformation protocol was: infection 20 min, co-culture 3 d, selection culture 30 d, and rooting 15 d. Out of a total of 288 sprouted shoots obtained from TESRR, 34 shoots (11.8 %) yielded GFP expression. In contrast, only 2 (3.0 %) of the 67 sprouted shoots from epicotyl transformation yielded GFP expression. In all plants showing the green fluorescence an expected 500 bp GFP fragment was proved by PCR analysis. Southern blot analysis further confirmed the integration of GFP gene into citrus genome. Transgenic plantlets were obtained within 80 d using the TESRR, compared within 150 d by using epicotyls.

Effects of ozone on wild type and transgenic tobacco

J. Guo, X. F. Li, D. M. Qi, S. Y. Chen, Z. Q. Li, I. Nijs, Y. G. Li, G. S. Liu

Biologia plantarum 53:670-676, 2009 | DOI: 10.1007/s10535-009-0121-0

Tocopherol cyclase (TC, encoded by gene VTE1) catalyzes the penultimate step of tocopherol synthesis. In this study we used wild type and transgenic tobacco plants overexpressing VTE1 from Arabidopsis to examine the role of tocopherol in ozone sensitivity. Wild type plants responded to an 4-h exposure to 300 nmol mol-1 ozone by severe leaf necrosis while the transgenic lines exhibited limited injury. Compared with the wild type, VTE1-overexpressing plants had lower increase in hydrogen peroxide, malondialdehyde contents and ion leakage, and lower decrease of net photosynthetic rate 48 h following the ozone exposure. Transgenic plants also better maintained the structural integrity of the photosynthetic apparatus.

An efficient in vitro regeneration system for Lythrum salicaria

A. U. Turker, B. Yucesan, E. Gurel

Biologia plantarum 53:750-754, 2009 | DOI: 10.1007/s10535-009-0137-5

This report describes an efficient plant regeneration system for the medicinal plant Lythrum salicaria via direct adventitious shoot development from leaf and stem explants. Leaf explants were much more responsive to regeneration than stem segments. Of the hormonal combinations tested, those involving thidiazuron (TDZ; 0.1, 0.3 or 0.5 mg dm-3) were more effective than the combinations of other hormones and 0.1 mg dm-3 TDZ combined with either indole-3-acetic acid (IAA) or indole-3-butyric acid (IBA) was the most productive. Rooting was readily achieved when multiple shoots were singled out and cultured on medium containing different auxins. IAA was the most effective on root development in terms of both the number of roots per shoot and the frequency of rooted shoots. More than 90 % of the regenerants survived after hardening for four weeks at gradually decreased air humidity.

Effect of abscisic acid on photosynthetic parameters during ex vitro transfer of micropropagated tobacco plantlets

J. Pospí¹ilová, H. Synková, D. Haisel, P. Ba»ková

Biologia plantarum 53:11-20, 2009 | DOI: 10.1007/s10535-009-0003-5

The aim of this research was to determine whether exogenous abscisic acid (ABA) applied immediately after ex vitro transfer of in vitro grown plants can improve their acclimatization. Tobacco (Nicotiana tabacum L.) plantlets were transferred into pots with Perlite initially moistened either by water or 50 µM ABA solution and they were grown under low (LI) or high (HI) irradiance of 150 and 700 µmol m-2 s-1, respectively. Endogenous content of ABA in tobacco leaves increased considerably after ABA application and even more in plants grown under HI. Stomatal conductance, transpiration rate and net photosynthetic rate decreased considerably 1 d after ex vitro transfer and increased thereafter. The gas exchange parameters were further decreased by ABA application and so wilting of these plants was limited. Chlorophyll (a+b) and β-carotene contents were higher in ABA-treated plants, but the content of xanthophyll cycle pigments was not increased. However, the degree of xanthophyll cycle pigments deepoxidation was decreased what also suggested less stress in ABA-treated plants. No dramatic changes in most chlorophyll a fluorescence parameters after ex vitro transfer suggested that the plants did not suffer from restriction of electron transport or photosystem damage.

A new RAPD marker for beet necrotic yellow vein virus resistance gene in Beta vulgaris

R. Amiri, M. Mesbah, M. Moghaddam, M. R. Bihamta, S. A. Mohammadi, P. Norouzi

Biologia plantarum 53:112-119, 2009 | DOI: 10.1007/s10535-009-0015-1

RAPD markers linked to beet necrotic yellow vein virus (BNYVV) resistance genes were identified in two Beta vulgaris accessions Holly-1-4 and WB42 using bulked segregant analysis. The polymorphism revealed by the RAPD markers in the F2 generations of WB42 was higher than that of Holly-1-4. The segregation distortion at marker loci was slightly lower in the B. vulgaris × B. maritima cross than in the B. vulgaris × B. vulgaris cross. For Holly-1-4, a RAPD marker was identified in a long distance from the resistance gene of Rz 1 . However, a RAPD marker tightly linked with Rz 2 gene in repulsion phase was detected with an approximate distance of 0.036 rf. This marker was not generation specific and showed high repeatability. The distance between Rz 1 and Rz 2 genes was estimated as 0.464 rf. After the Rz 2 Rz 2 and Rz 2 rz 2 genotypes were identified using ELISA values and repulsion phase RAPD markers, comparison of their ELISA means revealed lack of the gene dosage effects. Nevertheless, under the field or severe infection conditions, the difference between ELISA mean values of the Rz 2 Rz 2 and Rz 2 rz 2 genotypes might be more than that observed in this study and the gene dosage effects of Rz 2 allele might be important.

Enhanced chilling tolerance in Zoysia matrella by pre-treatment with salicylic acid, calcium chloride, hydrogen peroxide or 6-benzylaminopurine

Y. Wang, Z. M. Yang, Q. F. Zhang, J. L. Li

Biologia plantarum 53:179-182, 2009 | DOI: 10.1007/s10535-009-0030-2

Following leaf application of salicylic acid (SA), calcium chloride, hydrogen peroxide and 6-benzylaminopurine (BA), Manila grass (Zoysia matrella) plants were exposed to day/night temperature of 7/2 °C for 120 h in a growth chamber. The lower content of malondialdehyde (MDA) and H2O2 and higher activities of ascorbate peroxidase (APX), guaiacol peroxidase (POD) and catalase (CAT) during exposure to low temperature in pre-treated plants in comparison with control plants demonstrated that these compounds improved the chilling tolerance of Manila grass.

Proteomic analysis of bacterial blight defence signalling pathway using transgenic rice overexpressing thaumatin-like protein

T. Mahmood, A. Jan, S. Komatsu

Biologia plantarum 53:285-293, 2009 | DOI: 10.1007/s10535-009-0052-9

Rice overexpressed thaumatin-like protein gene and the proteins from the leaf blades of 2-week-old transgenic rice seedlings were fractionated into cytosolic and membrane fractions, and separated by two-dimensional polyacrylamide gel electrophoresis and stained with Commassie brilliant blue. Among of 440 detected proteins, 5 proteins were up-regulated and 5 proteins were down-regulated by the overexpression of thaumatin-like protein. In the sense thaumatin-like protein transgenic rice and/or in rice inoculated with Xanthomonas oryzae pv. oryzae (Xo7435), 2-cys peroxiredoxin, thaumatin-like protein and glycine cleavage H protein were up-regulated, while oxygen evolving complex protein 2 was down-regulated. These results suggest that thaumatin-like protein-mediated disease resistance of rice against bacterial blight disease is the results of changes in proteins related to oxidative stress and energy metabolism in addition to changes in proteins related to defence.

Low doses of ultraviolet-B or ultraviolet-C radiation affect phytohormones in young pea plants

Z. Katerova, S. Ivanov, E. Prinsen, H. Van Onckelen, V. Alexieva, A. Azmi

Biologia plantarum 53:365-368, 2009 | DOI: 10.1007/s10535-009-0068-1

Pea (Pisum sativum L., cv. Scinado) seedlings were exposed to low doses of ultraviolet-B (UV-B; 4.4 and 13.3 kJ m-2 d-1) or UV-C (0.1 and 0.3 kJ m-2 d-1) radiation for 14 d. Aminocyclopropane carboxylic acid (ACC), indoleacetic acid (IAA) and abscisic acid (ABA) contents were quantified by gas chromatography coupled to mass spectrometry (GC-MS). The accumulation of ACC upon irradiation was dose-dependent. ABA content was reduced and IAA content increased upon UV-C treatment whereas the UV-B doses used did not cause significant changes in ABA and IAA contents.

Molecular and cytological characterization of ZTL in Ipomoea nil

A. Zienkiewicz, D. J. Smoliñski, K. Zienkiewicz, P. Glaziñska, W. Wojciechowski, J. Kopcewicz

Biologia plantarum 53:435-443, 2009 | DOI: 10.1007/s10535-009-0083-2

The ZEITLUPE (ZTL) protein is involved in the control of circadian period, hypocotyl elongation and flowering time in Arabidopsis thaliana. The aim of the present work was the identification of the InZTL gene and localization of its mRNA in the model short-day plant Ipomoea nil. The deduced InZTL protein of 622 amino acid residues contained a LOV domain at the N-terminal part, followed by an F-box domain and six carboxy terminal kelch repeats. Amino acid sequence of InZTL showed 84 % homology with Mesembryanthemum crystallinum ZTL (McZTL) and 83 % with Arabidopsis thaliana ZTL (AtZTL). Fluorescence in situ hybridization (FISH) to InZTL mRNA showed its high accumulation in the vascular bundles as well in the guard cells of the cotyledon. Immunolocalization of ZTL protein indicated a similar distribution pattern of ZTL protein as InZTL mRNAs.

Defence responses of chilli fruits to Colletotrichum capsici and Alternaria alternata

T. Anand, R. Bhaskaran, T. Raguchander, R. Samiyappan, V. Prakasam, C. Gopalakrishnan

Biologia plantarum 53:553-559, 2009 | DOI: 10.1007/s10535-009-0100-5

The induction of defence compounds and enzymes involved in the phenylpropanoid pathway were studied in the ripe and green chilli fruits inoculated with Colletotrichum capsici and Alternaria alternata. Total phenols and the activity of phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenol oxidase (PPO) and catalase (CAT) increased in the inoculated ripe and green chilli fruits compared to the corresponding healthy fruits. Total phenols and the activities of the enzymes were at the maximum 2-3 d after inoculation and thereafter declined sharply in ripe chilli fruits, whereas slowly in green chilli fruits. In comparison with ripe chilli fruits, green chilli fruits were more resistant as they showed higher accumulation of total phenols and also higher activities of enzymes.

Production of transgenic Podophyllum peltatum via Agrobacterium tumefaciens-mediated transformation

V. R. Anbazhagan, Y. -S. Kim, Y. -E. Choi

Biologia plantarum 53:637-642, 2009 | DOI: 10.1007/s10535-009-0116-x

Transgenic Podophyllum peltatum plants were successfully produced by Agrobacterium tumefaciens-mediated transformation. Embryogenic callus was co-cultivated with Agrobacterium tumefaciens harboring a binary vector pBI 121 carrying β-glucuronidase (GUS) and neomycinphosphotransferase (NPT II) gene. GUS-histochemical analysis revealed that, 50 µM acetosyringone treatments during Agrobacterium infection and 3 d co-cultivation with Agrobacterium showed enhanced transformation efficiency. Percentage of GUS positive callus increased rapidly as the subculture time proceeded on selection medium containing 100 mg dm-3 kanamycin. Kanamycin resistant somatic embryos were formed from embryogenic callus after cultivation with 11.35 µM abscisic acid (ABA) for 3 weeks and then on hormone-free selection medium. Somatic embryos were germinated and converted into plantlets on medium containing 2.89 µM gibberellic acid (GA3). The integration of GUS and NPT II gene into transgenic plants was confirmed by polymerase chain reaction and Southern analysis.

Low concentration of exogenous abscisic acid increases lead tolerance in rice seedlings

L. Zhao, J. Xiong, L. P. Li, C. Zhu

Biologia plantarum 53:728-732, 2009 | DOI: 10.1007/s10535-009-0132-x

The effects of exogenous abscisic acid (ABA) on lead tolerance in rice (Oryza sativa L.) seedlings were investigated. Pre-treatment with 0.1 g m3 ABA for 2 d restricted amount of Pb translocated from roots to shoots, decreased malondialdehyde and H2O2 contents in leaves, and alleviated Pb-induced decrease in plant growth and leaf chlorophyll content. Further, ABA pre-treatment adjusted leaf antioxidative enzyme activities (increased ascorbate peroxidase and catalase activities while decreased superoxide dismutase activity) and so alleviated oxidative stress.

Microarray analysis of Arabidopsis genome response to aluminum stress

S. B. Goodwin, T. R. Sutter

Biologia plantarum 53:85-99, 2009 | DOI: 10.1007/s10535-009-0012-4

To better understand the mechanisms involved in aluminum toxicity and tolerance in plants, microarray technology was used to evaluate changes in gene expression in Arabidopsis thaliana under Al stress. With the use of Affymetrix Arabidopsis ATH1 Genechip, a comparison of RNA expression profiles was made between control and Al-treated Arabidopsis seedlings. A total of 256 genes were identified as Al-responsive. Ninety-four genes were shown to be up-regulated and 162 were down-regulated; comprising 1.1 % of the 24 000 Arabidopsis genes. Real-time RT-PCR was used to confirm the microarray data. The analysis showed that a large number of transcription factors and several putative signaling components were up-regulated by aluminum. Chloroplast structural and photosynthetic genes were, in general, down-regulated. A number of previously identified Al-responsive genes, e.g. GST, Auxin-regulated, Peroxidase, and Chitinase, were up-regulated by Al-stress, whereas Wali 3 and Wali 4 were down-regulated. We also identified several up-regulated genes involved in vacuolar signaling, sorting and docking. Three genes were also up-regulated by Al-stress, Ras GTP-binding protein, ABC-cassette binding, and the AtELP1 receptor genes, have previously been documented as responsive to drought and/or oxidative stress and may play important roles the detoxification of Al ions by transportation and storage into root vacuoles. Ultrastructural changes in the roots tips cells of Arabidopsis were evaluated using transmission electron microscopy and energy-dispersive X-ray analysis with scanning electron microscopy and results showed Al accumulation in the root tips of Arabidopsis.

Determination of genetic stability of long-term micropropagated plantlets of Platanus acerifolia using ISSR markers

W. J. Huang, G. G. Ning, G. F. Liu, M. Z. Bao

Biologia plantarum 53:159-163, 2009 | DOI: 10.1007/s10535-009-0025-z

Inter-simple sequence repeat (ISSR) markers were used to assess the genetic stability of long-term micropropagated plantlets of London plane tree (Platanus acerifolia Willd.). Twenty micropropagated plantlets were chosen from a clonal collection of shoots that originated from a single mother shoot. This clonal collection had been maintained under in vitro culture conditions for at least 8 years, as achieved by axillary branch multiplication. Out of 38 ISSR primers screened, 16 primers were found to produce clear reproducible bands resulting in a total of 103 distinct bands with an average of 6.44 scorable bands per primer. Of these 103 bands, 86 were monomorphic across all 20 of the plants tested and 17 showed polymorphisms (16.5 % polymorphism). Based on the ISSR band data, similarity indices between the plantlets ranged from 0.92 to 1.00. These similarity indices were used to construct an UPGMA dendrogram and demonstrated that all 20 micropropagated plants grouped together in one major cluster with a similarity level of 91 %. A total of 1771 scorable bands were obtained from the full combination of primers and plantlets and only 51 (2.88 %) were polymorphic across the plantlets which indicates that this micropropagated line of P. acerifolia is genetically stable.

Response of maize genotypes to salinity stress in relation to osmolytes and metal-ions contents, oxidative stress and antioxidant enzymes activity

J. Kholová, R. K. Sairam, R.C. Meena, G. C. Srivastava

Biologia plantarum 53:249-256, 2009 | DOI: 10.1007/s10535-009-0047-6

Effect of long term soil salinity (control-S0 and three levels S1 to S3) was studied in two maize (Zea mays L.) genotypes, PEHM 3 (comparatively tolerant) and Navjot (susceptible) at vegetative and anthesis stages during summer-rainy season. Salinity stress decreased relative water content (RWC), chlorophyll (Chl) and carotenoid (Car) contents, membrane stability index (MSI), potassium and calcium contents, and increased the contents of superoxide radical (O2 .-), hydrogen peroxide (H2O2), thiobarbituric acid reactive substances (TBARS), proline, glycinebetaine, total soluble sugars, and sodium, and Na+/K+ and Na+/Ca2+ ratios in both the genotypes. Contents of zinc, copper, manganese and iron increased up to S2. Though under S0 PEHM 3 had higher content of all the metals, Navjot recorded higher content of Zn at all salinity levels and contents of all metal ions at S2 and S3. Activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR) increased upto S2 in both the genotypes, and upto S3 in PEHM 3 at the two stages. Salinity induced decrease in RWC, Chl, Car, MSI, K+ and Ca2+ was significantly greater in Navjot, which also recorded higher Na+ content and Na+/K+ and Na+/Ca2+ ratios than PEHM-3. PEHM-3 recorded higher contents of proline, glycine-betaine, total soluble sugars, K+, Ca2+, activity of SOD, APX, CAT, GR, and comparatively lower O2 .-, H2O2 and TBARS contents compared to Navjot.

Genetic diversity assessment in greek Medicago truncatula genotypes using microsatellite markers

P. Akritidis, P. V. Mylona, A. S. Tsaftaris, A. N. Polidoros

Biologia plantarum 53:343-346, 2009 | DOI: 10.1007/s10535-009-0063-6

In this study we examined the genetic diversity and geographic scale of genotype distribution within the model legume species Medicago truncatula widely distributed in pasture and marginal agricultural lands in Greece and other Mediterranean countries. Thirty one Medicago truncatula and Medicago littorialis accessions were chosen on the basis of their geographical distributions and studied using 9 polymorphic simple sequence repeats (SSR) markers. The number of alleles per locus varied between 3 and 7. A total of 42 alleles were detected with a mean value of 4.66 alleles per locus. Geographic origin was not related with genotypic similarity among accessions. However, there were instances of close genetic relatedness between accessions from neighboring locations in a geographic compartment. In conclusion, the presented data revealed extensive M. truncatula genotype dispersal in Greece pointing to the significance of preserving local genetic resources in their natural environment.

Synergid: a key link in fertilization of angiosperms

D. X. Li, M. Z. Lin, Y. Y. Wang, H. Q. Tian

Biologia plantarum 53:401-407, 2009 | DOI: 10.1007/s10535-009-0078-z

In over 80 % of the angiosperms, the female gametophyte is comprised of seven cells, two of which are the synergid cells. These cells are considered pivotal in assuring successful fertilization. The synergid cells direct pollen tube growth toward the female gametophyte, and facilitate the entrance of the tube into the embryo sac. Once the pollen tube enters the synergid cell, its growth is arrested, the tip of the tube breaks, and two sperm cells are released. This sequence of events is also synergid dependent. In addition, separation of the cells of the male germ unit, orientation of the two sperm cells in the degenerating synergid, and fusion of the egg and central cell with sperm cells may also be related to synergid cells. Synergid structure has been widely studied, but development and function of these cells during angiosperm fertilization remains elusive. Recent molecular approaches have provided an enhanced understanding of the role of synergid cells in fertilization. The present review summarizes the results of current studies regarding the role of synergids in angiosperm reproductive function.

Contractile roots are the most sensitive organ in Crocus sativus to salt stress

S. M. Rajaei, V. Niknam, S. M. Seyedi, H. Ebrahimzadeh, K. Razavi

Biologia plantarum 53:523-529, 2009 | DOI: 10.1007/s10535-009-0095-y

Crocus sativus corms were grown in Perlite and watered by half-strength modified Hoagland nutrient solution containing 0, 50, 100, 150, 200 mM NaCl. Growth parameters and contents of proteins, proline, polyphenols, minerals and saccharides were studied in fibrous roots, contractile roots, corms and leaves. All plants remained alive and did not display any sign of foliar damage even at 200 mM NaCl. However, the salinity decreased growth, relative water content and increased contents of proline and Na+ in all organs. Total protein content was increased in corms and contractile roots but decreased in fibrous roots. Changes in protein pattern were also observed. Polyphenol content was increased by salinity in all organs except the leaves. As salinity increased, content of soluble saccharides decreased except in the contractile roots.

Somatic embryogenesis and regeneration of Cenchrus ciliaris genotypes from immature inflorescence explants

C. B. Yadav, P. Jha, C. Mahalakshmi, V. Anjaiah, V. Bhat

Biologia plantarum 53:603-609, 2009 | DOI: 10.1007/s10535-009-0111-2

An efficient, highly reproducible system for plant regeneration via somatic embryogenesis was developed for Cenchrus ciliaris genotypes IG-3108 and IG-74. Explants such as seeds, shoot tip segments and immature inflorescences were cultured on Murashige and Skoog (MS) medium supplemented with 2.0-5.0 mg dm-3 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg dm-3 N6-benzyladenine (BA) for induction of callus. Callus could be successfully induced from all the three explants of both the genotypes. But the high frequency of embryogenic callus could be induced only from immature inflorescence explants. Somatic embryos were formed from nodular, hard and compact embryogenic calli when 2,4-D concentration was gradually reduced and BA concentration increased. Histological studies of somatic embryos indicated the presence of shoot apical meristem with leaf primordia. Ultrastructural details of globular and scutellar somatic embryos further validated successful induction and progression of somatic embryogenesis. Shoots were differentiated upon germination of somatic embryos on MS medium containing 2,4-D (0.25 mg dm-3) and BA or kinetin (1-5 mg dm-3). Roots were induced on 1/2 MS medium containing charcoal (0.8 %), and the regenerated plants transferred to pots and established in the soil showed normal growth and fertility.

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