Direct shoot regeneration from Arabidopsis thaliana shoot apical meristems

W. Xin, Z. Liu, Y. Song, T. Hou, F. Xiang

Biologia plantarum 2012, 56:601-606 | DOI: 10.1007/s10535-012-0127-x

In Arabidopsis thaliana in vitro culture, shoots were induced from the shoot apical meristem (SAM) of germinating seeds in the presence of 2,4-dichlorophenoxyacetic acid. Primary shoot primordia developed leaf-like structures, from which secondary shoot primordia were produced. Regenerated shoots were recovered when the material was transferred to a medium lacking auxin. Adventitious roots formed from a callusing basal region of the secondary shoots. The CUC1 transcription factor was expressed at the apex of the primary shoot primordium and at the boundary between the regenerated SAM and the developing leaf primordia. The DR5::GUS...

Effect of N⁶-benzyladenine and indole-3-butyric acid on photosynthetic apparatus of Orthosiphon stamineus plants grown in vitro

D. Stoyanova-Koleva, M. Stefanova, M. Zhiponova, V. Kapchina-Toteva

Biologia plantarum 2012, 56:607-612 | DOI: 10.1007/s10535-012-0060-z

The leaf structure and chloroplast ultrastructure of kidney tea (Orthosiphon stamineus Benth.) was studied in in vitro culture on standard MS medium supplemented with or without plant growth regulators (PGRs). The cytokinin N⁶-benzyladenine (BA) negatively affected the structure of the palisade parenchyma and chloroplast ultrastructure and increased the stomatal frequency of the adaxial epidermis. The auxin indole-3-butyric acid (IBA) did not modify the morphology of regenerated leaf tissues as well as the chloroplast ultrastructure. The effect of both PGRs applied in combination was manifested in well-differentiated mesophyll...

Changes in protein pattern during different developmental stages of somatic embryos in chickpea

S. Mishra, I. Sanyal, D. V. Amla

Biologia plantarum 2012, 56:613-619 | DOI: 10.1007/s10535-012-0124-0

Mature embryonic axes were used for chickpea (Cicer arietinum L.) regeneration via somatic embryogenesis. Qualitative and quantitative estimation of protein profile during somatic embryogenesis by SDS-PAGE and densitometric analysis showed differential expression of various storage proteins at different stages of somatic embryo development, which was compared with the profile of developing seeds. Total protein content in somatic embryos of chickpea increased from globular stage [2.9 μg mg^-1(f.m.)] to cotyledonary stage [4.8 μg mg^-1(f.m.)] and then started decreasing during onset of maturation and germination...

A pattern of unique embryogenesis occurring via apomixis in Carya cathayensis

B. Zhang, Z. J. Wang, S. H. Jin, G. H. Xia, Y. J. Huang, J. Q. Huang

Biologia plantarum 2012, 56:620-627 | DOI: 10.1007/s10535-012-0256-2

Apomixis represents an alteration of classical sexual plant reproduction to produce seeds that have essentially clonal embryos. In this report, hickory (Carya cathayensis Sarg.), which is an important oil tree, is identified as a new apomictic species. The ovary has a chamber containing one ovule that is unitegmic and orthotropous. Embryological investigations indicated that the developmental pattern of embryo sac formation is typical polygonum-type. Zygote embryos were not found during numerous histological investigations, and the embryo originated from nucellar cells. Nucellar embryo initials were found both at the micropylar and chalazal...

Tapetum-specific expression of harpin_Pss causes male sterility in transgenic tobacco

B. Madhuri, S. Raut, D. Dey, A. Nazneen, B. Uma, A. R. Podile

Biologia plantarum 2012, 56:628-634 | DOI: 10.1007/s10535-012-0123-1

Harpin, an elicitor molecule of bacterial origin induces hypersensitive response (HR) in non-host plants. In an attempt to induce male sterility, harpin was tagged with a signal peptide and expressed downstream to tapetum-specific TA29 promoter resulting in extracellular secretion, subsequent degeneration of tapetum and development of male sterility in tobacco. Putative transgenics were analyzed by PCR amplification of transgene, semiquantitative RT-PCR analysis from total RNA extracts from anther tissue with transgene specific probe, Western blotting using polyclonal antibody raised against harpin, by transmission and scanning electron microscopy,...

Modified alternative oxidase expression results in different reactive oxygen species content in Arabidopsis cell culture but not in whole plants

V. I. Tarasenko, E. Y. Garnik, V. N. Shmakov, Y. M. Konstantinov

Biologia plantarum 2012, 56:635-640 | DOI: 10.1007/s10535-012-0115-1

Alternative oxidase (AOX) transfers electrons from ubiquinone to oxygen in the respiratory chain of plant mitochondria. It is widely accepted that AOX functions as a mechanism decreasing the formation of reactive oxygen species (ROS) produced during respiratory electron transport. However, there are no experimental data to provide unambiguous proof of this hypothesis. We have studied growth characteristics, ROS content, and stress sensitivity in Arabidopsis transgenic lines with reduced or increased levels of AOX. We demonstrated that AOX-deficient plants grown in soil had an extended reproductive phase. Changes in AOX activity did not affect...

Identification and characterization of a novel gene encoding myb-box binding zinc finger protein in Gossypium arboreum

M. Zahur, A. Maqbool, M. Irfan, A. Jamal, N. Shahid, B. Aftab, T. Husnain

Biologia plantarum 2012, 56:641-647 | DOI: 10.1007/s10535-012-0255-3

Zinc finger proteins are encoded by the genes chiefly involved in stress resistance hormone signal transduction of plants. In this study, a cDNA encoding a zinc finger transcription factor was isolated by the yeast one-hybrid system from Gossypium arboreum using the MYB-box element of the universal stress gene (GUSP1) promoter as bait. The corresponding protein (named GaZnF) can bind specifically to a 13 bp MYB-box region. The GaZnF cDNA is 1093 bp in length, including a 510 bp open reading frame. The predicted GaZnF protein contains ANI-A20 motifs and shares a high sequence similarity with zinc finger proteins from other plants. Spatial...

Characterization of eight cytosolic sHSP genes and their expression in Capsella bursa-pastoris

P. Tao, L. Liu, J. B. Wang

Biologia plantarum 2012, 56:648-656 | DOI: 10.1007/s10535-012-0239-3

Small heat shock proteins (sHSPs) are crucial components of the plant response to heat shock. We identified and analyzed eight sHSP genes of Capsella bursa-pastoris to better understand the ability of this species to adapt. Eight genes were initially cloned and sequenced from the mature embryo cDNA pool. They belong to the cytosolic I (CI), cytosolic II (CII), and cytosolic III (CIII) subfamilies. One CI sHSP gene was homologous to that of C. rubella. Sequence analysis using 3' RACE revealed that there are two or more variable 3'-untranslated regions (UTRs) in these sHSP transcripts. The transcriptional levels of the eight...

Phylogenetic, structure and expression analysis of ABC1Ps gene family in rice

S. G. Yang, T. Li, M. Liu, S. J. Gao, S. Y. Yang, L. Li, C. W. Yang

Biologia plantarum 2012, 56:667-674 | DOI: 10.1007/s10535-012-0247-3

The ABC1 protein family (ABC1P), a new family of putative kinases, widely existed in procaryote and eucaryote. A comprehensive genome-wide analysis was carried out in this study to find all ABC1Ps in rice (Oryza sativa subsp. japonica). We identified 15 ABC1P genes in rice. All the ABC1Ps contained an ABC1 domain of about 120 conserved amino acid residues and conserved kinase motifs-VAIK (VAVK, VAMK) and DFG (DEG). The phylogenetic analysis showed that all the ABC1Ps were grouped into three subgroups, and formed a total of 12 sister pairs. Conserved motifs analysed by MEME program indicated that almost all ABC1Ps contains motifs...

Ascorbate deficient semi-dwarf asfL1 mutant of Lathyrus sativus exhibits alterations in antioxidant defense

D. Talukdar

Biologia plantarum 2012, 56:675-682 | DOI: 10.1007/s10535-012-0245-5

An ascorbate-deficient semi-dwarf mutant asfL-1 was detected in 250 Gy γ-ray treated grass pea (Lathyrus sativus L.) cv. BioR-231. The mutant contained only 42 % of leaf and 20 % of root ascorbate content of mother control (MC). I investigated the possible causes of ascorbate deficiency and its effect on growth and antioxidant defense in control and 150 mM NaCl-treated seedling after 60 d growth period. Ascorbate deficiency was due to significant reduction in activities of monodehydroascorbate reductase and dehydroascorbate reductase as well as increase in ascorbate oxidase, leading to considerable decrease in redox state....

Characterization of a drought inducible trithorax-like H3K4 methyltransferase from barley

D. Papaefthimiou, A. S. Tsaftaris

Biologia plantarum 2012, 56:683-692 | DOI: 10.1007/s10535-012-0125-z

Histone H3 lysine 4 methylations catalyzed by histone lysine methyltransferases (HKMTs), like the Arabidopsis thaliana ATX1 and ATX2, are important epigenetic modifications related to chromatin decondensation and gene activation. In order to study this epigenetic mechanism in monocot cereal plants, we performed homology searches of ATX1 and ATX2 against the Brachypodium distachyon L. Beauv and rice (Oryza sativa L. spp. japonica) genomes, discovering single homologues for each cereal crop representing both Arabidopsis sequences. Using this information, we employed the rolling circle amplification - rapid...

Cu/Zn superoxide dismutase activity and respective gene expression during cold acclimation and freezing stress in barley cultivars

C. Kayihan, F. Eyidogan, N. Afsar, H. A. Oktem, M. Yucel

Biologia plantarum 2012, 56:693-698 | DOI: 10.1007/s10535-012-0143-x

The transcript levels and activities of the superoxide dismutase isoenzyme (Cu/ZnSOD) were assessed in winter (Tarm-92) and spring (Zafer-160) barley cultivars during cold acclimation, freezing stress and after rewarming. Leaf Cu/ZnSOD activity and Cu/ZnSOD expression level were not significantly changed during cold acclimation. The Cu/ZnSOD expression increased evidently at mild freezing stress (-3 °C; F1), while Cu/ZnSOD1 activity did not show any response and Cu/ZnSOD2 activity decreased continuously during F1 and F2 (-7 °C) in Tarm-92. On the other hand, root Cu/ZnSOD2 activity was in accordance with Cu/ZnSOD expression in...

Salt- and osmotic stress-induced choline monooxygenase expression in Kochia scoparia is ABA-independent

E. B. Kalinina, B. K. Keith, A. J. Kern, W. E. Dyer

Biologia plantarum 2012, 56:699-704 | DOI: 10.1007/s10535-012-0132-0

Choline monooxygenase (CMO) is the first regulatory enzyme in the biosynthetic pathway for glycine betaine, an effective osmoprotectant in Kochia scoparia, a highly drought- and salt-tolerant species. In seedlings, CMO transcript levels are rapidly increased in response to both NaCl and osmotic stress treatments. The mRNA level in shoots was substantially higher than in roots. The rapid induction seen in whole plants was in contrast to the apparent down-regulation observed in suspension-cultured K. scoparia cells in response to the same salt stress. Treatment with exogenous abscisic acid (ABA) or fluridone shows that CMO induction proceeds...

Cytosolic NADP-isocitrate dehydrogenase in Arabidopsis leaves and roots

M. Leterrier, J. B. Barroso, J. M. Palma, F. J. Corpas

Biologia plantarum 2012, 56:705-710 | DOI: 10.1007/s10535-012-0244-6

NADP-dependent isocitrate dehydrogenase (NADP-ICDH) catalyses the production of NADPH, which is an essential component in the cellular homeostasis. In Arabidopsis, the kinetic parameters (K _m and V _max) of cytosolic NADP-ICDH were different in leaves and roots. In vitro applied H₂O₂ did not affect the NADP-ICDH activity in either organ, however, the reduced glutathione inhibited the activity in leaves but not in roots. On the other hand, S-nitrosoglutathione (a NO donor) and peroxynitrite depressed NADP-ICDH activity in leaves and roots.

Physiological and ultrastructural effects of lead on tobacco

R. Alkhatib, J. Maruthavanan, S. Ghoshroy, R. Steiner, T. Sterling, R. Creamer

Biologia plantarum 2012, 56:711-716 | DOI: 10.1007/s10535-012-0241-9

The effects of lead toxicity on leaf gas exchange, chlorophyll content, chlorophyll fluorescence, chloroplast ultrastructure, and opening of stomata were examined in tobacco (Nicotiana tabacum L.) plants. Plants were grown in a growth chamber for 7 d in Hoagland nutrient solution supplemented with 0.0 (control), 5, 10, 25, 50, 100, 300 and 500 μM Pb(NO₃)₂. Plants treated with 5, 10, and 25 μM Pb(NO₃)₂ exhibited no abnormalities. Root and shoot growth, net photosynthetic rate and stomatal conductance were significantly reduced in plants treated with 100, 300 and 500 μM Pb(NO₃)₂....

Nitrogen remobilization in shoots of Paris polyphylla is altered by gibberellic acid application during senescence

K. Yu, Q. L. Fan, J. R. Wei, D. Yu, J. R. Li

Biologia plantarum 2012, 56:717-723 | DOI: 10.1007/s10535-012-0116-0

Nitrogen remobilization during senescence has been studied in perennial herb Paris polyphylla. We analyzed changes in N content, amino acids, N-remobilization enzymes and effects of gibberellic acid (GA) during natural senescence. There was a gradual decrease in the contents of N, chlorophyll and soluble proteins and activities of glutamine synthetase (GS; EC 6.3.1.2) and glutamate dehydrogenase (GLDH; EC 1.4.1.2). Activity staining and Western blots showed that GS2 activity decreased, whereas GS1 activity was relatively stable over time. In contrast, the C/N ratio and total amino acid content increased. Among individual amino acids, the proportions...

Impact of short-term cadmium treatment on catalase and ascorbate peroxidase activities in barley root tips

B. Bočová, J. Huttová, Ľ. Liptáková, I. Mistrík, M. Ollé, L. Tamás

Biologia plantarum 2012, 56:724-728 | DOI: 10.1007/s10535-012-0129-8

The aim of this study was to analyse the relationship between root growth inhibition and alterations in catalase (CAT) and ascorbate peroxidase (APX) contents and activities in barley root tips during the recovery after short-term Cd stress. Significant root growth inhibition was observed after a relatively short-term (30 min) exposure of barley roots to low 15 μM Cd concentration. In seedlings treated with 30 μM Cd root growth was renewed 8-9 h after Cd treatment. By contrast, seedlings exposed to 60 μM Cd failed to restore root growth. The CAT activity increased after 15 μM Cd treatment, whereas, higher Cd concentrations inhibited CAT...

Cadmium exclusion a key factor in differential Cd-resistance in Thlaspi arvense ecotypes

S. R. Martin, M. Llugany, J. Barceló, C. Poschenrieder

Biologia plantarum 2012, 56:729-734 | DOI: 10.1007/s10535-012-0056-8

Differences in Cd accumulation and Cd tolerance between Thlaspi arvense ecotype Aigues Vives (AV) from a commercial grower in South France and ecotype Jena collected in the polluted urban area of Jena (Germany) were reported here. Ecotype Jena exhibited considerable Cd-tolerance. Shoot and root masses were unaffected and root elongation was even enhanced by exposure to 50 μM Cd. In contrast, growth of ecotype AV was severely affected by this Cd treatment. Ecotype Jena was much more efficient in excluding Cd from both roots and shoots than ecotype AV. Despite the efficient restriction of Cd transport from roots to shoots in Jena, this ecotype...

Engineering resistance against Tobacco streak virus (TSV) in sunflower and tobacco using RNA interference

K. Pradeep, V. K. Satya, M. Selvapriya, A. Vijayasamundeeswari, D. Ladhalakshmi, V. Paranidharan, R. Rabindran, R. Samiyappan, P. Balasubramanian, R. Velazhahan

Biologia plantarum 2012, 56:735-741 | DOI: 10.1007/s10535-012-0111-5

The coat protein (CP) gene of Tobacco streak virus (TSV) from sunflower (Helianthus annuus L.) was amplified, cloned and sequenced. A 421 bp fragment of the TSV coat protein gene was amplified and a gene construct encoding the hairpin RNA (hpRNA) of the TSV-CP sequence was made in the plasmid pHANNIBAL. The construct contains sense and antisense CP sequences flanking a 742 bp spacer sequence (Pdk intron) under the control of the constitutive CaMV35S promoter. A 3.6 kb Not I fragment containing the hpRNA cassette (TSV-CP) was isolated from pHANNIBAL and sub-cloned into the binary vector pART27. This chimeric gene construct...

Virus resistance obtained in transgenic tobacco and rice by RNA interference using promoters with distinct activity

C. Zhang, Y. Song, F. Jiang, G. Li, Y. Jiang, C. Zhu, F. Wen

Biologia plantarum 2012, 56:742-748 | DOI: 10.1007/s10535-012-0117-z

To induce virus resistance in tobacco and rice we constructed hairpin RNA expression system harbouring inverted repeat fragments of coat protein cDNA of Potato virus Y (PVY) or Rice stripe virus (RSV). These structures were driven by three promoters [cauliflower mosaic virus 35S (CaMV 35S), polyubiqutin gene of maize (Ubi), and Pharbitis nil leucine zipper gene (PNZIP)] which have different tissue-specific activity. PVY resistance ratios were 65.18, 24.33 and 83.54 % in transgenic tobacco plants harboring p35S-PVY, pUbi-PVY and pPNZIP-PVY. RSV resistance was 16.21, 28.61 and 29.33 % in transgenic rice plants harboring p35S-RSV,...

Visualisation of xylem sap flow direction in isolated fine lateral roots and estimation of the xylem sap osmotic potential

M. Fritz, R. Ehwald

Biologia plantarum 2012, 56:749-756 | DOI: 10.1007/s10535-012-0121-3

Xylem sap outflow from fine lateral roots (FLRs) isolated from hydroponically grown young maize (Zea mays L.) plants was visualized by local brightening of test solutions contrasted with purified Indian ink particles. Flow into the vessels was indicated by the adsorption of Evans Blue in their walls. The fraction of the FLRs able to exude xylem sap in a mineral medium with 30 mM mannitol decreased with increasing incubation time. This change was strongly retarded, when the FLRs were incubated in a medium containing glucose instead of mannitol. There was a broad range of variation of the osmotic potential of the test solutions (Ψ_so),...

Book Review

I. Babůrek

Biologia plantarum 2012, 56:798 | DOI: 10.1007/s10535-012-0262-4

Book Review

N. Wilhelmová

Biologia plantarum 2012, 56:799 | DOI: 10.1007/s10535-012-0263-3

Book Review

L. Burketová

Biologia plantarum 2012, 56:800 | DOI: 10.1007/s10535-012-0264-2

Early gene expression in the walnut tree occurring during stimulation of leaf hydraulic conductance by irradiance

K. Ben Bâaziz, D. Lopez, S. Bouzid, H. Cochard, J. -S. Venisse, S. Sakr

Biologia plantarum 2012, 56:657-666 | DOI: 10.1007/s10535-012-0120-4

Leaf hydraulic conductance (K_leaf) plays a significant part in plant-water regulation. In walnut leaves, K_leaf is stimulated by irradiance and closely relates to the accumulation of JrPIP2s aquaporin transcripts, but it is independent of stomatal aperture. To provide an insight into the early molecular events occurred during light-induced K_leaf, a large-scale transcriptomic analysis consisting of the cDNA-amplified fragment length polymorphism (AFLP) was carried out on walnut leaves maintained under irradiance or in darkness. Of the total 12 000 transcript-derived fragments (TDFs) obtained using cDNA-AFLP with...

Putrescine modulates antioxidant defense response in wheat under high temperature stress

B. Asthir, A. Koundal, N. S. Bains

Biologia plantarum 2012, 56:757-761 | DOI: 10.1007/s10535-012-0209-1

Effects of putrescine (Put) on responses of wheat (Triticum aestivum) seedlings or detached tillers at mid-milky stage to high temperature (HT) stress were investigated. The heat tolerant cv. PBW 343 exhibited higher content of antioxidants and activities of antioxidative enzymes, while lower content of lipid peroxides as compared to the heat-sensitive cv. HD 2329. HT elevated peroxidase (POX) and superoxide dismutase (SOD) activities, while diamine oxidase (DAO) and polyamine oxidase (PAO) activities were reduced in roots, shoots and developing grains. Application of Put under HT further enhanced POX and SOD activities along with increased...

Expression of Na⁺/H⁺ antiporter gene in response to water and salinity stress in grapevine rootstocks

A. Upadhyay, A. K. Upadhyay, R. A. Bhirangi

Biologia plantarum 2012, 56:762-766 | DOI: 10.1007/s10535-012-0240-x

Grapevine rootstocks belonging to different species of Vitis differ in their response to stress. Vines of rootstocks 110R and 1613C were subjected to different salt and water stresses individually and in combination. Expression of VvNHX1, a Na⁺/H⁺ antiporter gene, was analyzed at 7 and 21 d of stress treatment. In 110R, the expression of VvNHX1 gene increased in response to both salinity and water stress already after 7 d. Under salinity and combined stress enhanced expression of this gene was observed also after 21 d whereas expression decreased under water stress. In 1613C, expression of this gene did not...

Amelioration of salt-induced oxidative stress in eggplant by application of 24-epibrassinolide

H. -D. Ding, X. -H. Zhu, Z. -W. Zhu, S. -J. Yang, D. -S. Zha, X. -X. Wu

Biologia plantarum 2012, 56:767-770 | DOI: 10.1007/s10535-012-0108-0

The effects of exogenous 24-epibrassinolide (EBR) on the growth, oxidative damage, antioxidant system and ion contents in eggplant (Solanum melongena L.) seedlings under salt stress were investigated. Eggplant seedlings were exposed to 90 mM NaCl with 0, 0.025, 0.05, 0.10 and 0.20 mg dm^-3 EBR for 10 d. EBR, especially at concentration 0.05 mg dm^-3, alleviated growth suppression caused by NaCl stress, decreased electrolyte leakage, superoxide production and content of malondialdehyde and H₂O₂ in NaCl-treated plants. EBR also increased activities of superoxide dismutase, guaiacol peroxidase, catalase...

Stomatal NH₃ compensation point and its metabolic regulation in senescence phenotypes of Nicotiana tabacum

W. J. Duan, T. Z. Yang, Y. Dai, D. L. Li, X. Q. Zhang, H. B. Liu, N. Li, C. G. Wang

Biologia plantarum 2012, 56:771-774 | DOI: 10.1007/s10535-012-0141-z

We compared stomatal ammonia compensation point (χ_s) and its metabolic regulation in tobacco (Nicotiana tabacum) leaves of a quick-leaf-senescence phenotype ZY90 and a slow-leaf-senescence phenotype NC89. Compared with NC89, ZY90 had significantly higher χ_s values between 40 and 60 d after leaf sprouting in spite of its lower nitrogen content. During the same time, a steeper decline in glutamine synthetase activity was detected in ZY90 leaves, simultaneously with a steep increase in χ_s. These results suggested that the quick leaf senescence phenotype exhibited high NH₃ emission potential...

The influence of the N- and C- terminal modifications of Potato virus X coat protein on virus properties

H. Hoffmeisterova, T. Moravec, H. Plchova, J. Folwarczna, N. Cerovska

Biologia plantarum 2012, 56:775-779 | DOI: 10.1007/s10535-012-0130-2

The Potato virus X (PVX)-based vector was used for the construction of N- and C-terminally modified PVX coat protein (XCP) chimeras. N-terminal XCP modifications do not influence the viral life cycle, whereas the simple XCP C-terminal fusion impedes the viral replication. We designed several C-terminally modified XCP chimeras and tested their viabilities in various Nicotiana benthamiana genotypes. Our results showed the negative impact of 3'-terminal modification of XCP on the chimera's life cycle. To ensure chimeric constructs stability, the second copy of the last 60 nucleotides of XCP followed by the 3'-untranslated region (UTR) was...

Pretreatment with 5-aminolevulinic acid mitigates heat stress of cucumber leaves

J. Zhang, D. -M. Li, Y. Gao, B. Yu, C. -X. Xia, J. -G. Bai

Biologia plantarum 2012, 56:780-784 | DOI: 10.1007/s10535-012-0136-9

Cucumber seedlings were pretreated with 3 μM 5-aminolevulinic acid (ALA) followed by cultivation at normal (25/18 °C) or high (42/38 °C) day/night temperature to investigate the protective effects of ALA on heat stress in plants. Heat elevated the contents of malondiadehyde (MDA), superoxide radical (O₂ ^.-) and hydrogen peroxide (H₂O₂) in leaves of all plants but less in ALA-pretreated plants. Heat treatment resulted in higher antioxidant enzyme activities and proline and soluble sugar contents and weaker growth inhibition in ALA-pretreated plants than in those treated with heat alone. These results indicate...

Effects of temperature and irradiance on photosystem activity during Alhagi sparsifolia leaf senescence

W. Xue, X. Y. Li, J. T. Zhu, L. S. Lin

Biologia plantarum 2012, 56:785-788 | DOI: 10.1007/s10535-012-0145-8

During the period of senescence of desert plant Alhagi sparsifolia Shap. the maximum photochemical quantum yield measured as variable to maximum fluorescence ratio (F_v/F_m) remained relatively high, although the number of active reaction centres per cross section (RCs) decreased significantly. The efficiency of electron acceptors beyond the primary quinone acceptor (Q_A) decreased. The effect of temperature and irradiance on photosystem activity was maximum after 6 d. Our results suggest that: 1) the down-regulation of photosystem activity was due to the decline of both RCs and electron acceptance between...

New polymorphic microsatellite loci for Theobroma cacao: isolation and characterization of microsatellites from enriched genomic libraries

E. S. L. Santos, C. B. M. Cerqueira-Silva, G. M. Mori, D. Ahnert, R. X. Corrêa, A. P. Souza

Biologia plantarum 2012, 56:789-792 | DOI: 10.1007/s10535-012-0134-y

Seventeen polymorphic microsatellite markers were isolated from enriched genomic libraries for Theobroma cacao, providing additional tools for studying the genetic diversity and map saturation of this species. These markers were characterized in 32 accessions of the T. cacao germplasm collection from the Centro de Pesquisas do Cacau. The number of alleles at each locus varied from 2 to 8, with an average of 4.41 alleles per locus. The polymorphism information content varied from 0.060 to 0.695, with an average of 0.333. The markers characterized in this study will be employed in map saturation studies and diversity assessments of cacao...

Role of antioxidative system during the development and senescence of cucumber fruit

C. -L. Qian, Y. -Y. Zhao, H. -B. Mi, X. -H. Chen, L. -J. Guo, L. -C. Mao

Biologia plantarum 2012, 56:793-797 | DOI: 10.1007/s10535-012-0126-y

The oxidative processes and antioxidative system in cucumber (Cucumis sativus L.) fruit were determined during development and senescence. Four distinct developmental stages could be delineated during fruit maturation: immature (3-8 d after anthesis, DAA), mature (9-16 DAA), breaker (17-22 DAA), and yellow (35-40 DAA). The electrolyte leakage, malondialdehyde content, superoxide anion production rate, and hydrogen peroxide content increased continuously during fruit development and senescence. Superoxide dismutase and peroxidase activities consistently increased during fruit maturation, and the catalase activity displayed a single peak at the...