Biologia plantarum, 2011 (vol. 55), issue 4

Article

Molecular cloning and phylogenetic analysis of cereal type II metacaspase cDNA from wheat

E. Piszczek, M. Dudkiewicz, M. Sobczak

Biologia plantarum 2011, 55:614 | DOI: 10.1007/s10535-011-0159-7

A new cereal type II metacaspase full-length cDNA from wheat (Triticum aestivum L.) leaves, TaeMCAII, was for the first time successfully amplified and sequenced. The full-length sequence of the TaeMCAII cDNA of 1 551 bp contains a 1 218 bp open reading frame. The deduced protein encoded by the TaeMCAII cDNA consists of 405 amino acids with a calculated molecular mass of 44 kDa and an isoelectric point of 5.29. In response to wounding or heat shock, a similar sequence of ultrastructural events including the tonoplast rupture, chromatin condensation, degradation of chloroplasts and disappearance of cytoplasm and organelles...

Characterization and expression analysis of the SNF2 family genes in response to phytohormones and abiotic stresses in rice

X. -Y. Li, C. Wang, P. -P. Nie, X. -W. Lu, M. Wang, W. Liu, J. Yao, Y. -G. Liu, Q. -Y. Zhang

Biologia plantarum 2011, 55:625 | DOI: 10.1007/s10535-011-0160-1

The function of SNF2 ATPases, the major catalytic subunits of chromatin remodeling complexes, in plants is not sufficiently understood. Here we identified 39 putative SNF2 genes of rice (Oryza sativa L.) by homology analyses and analyzed the expression profiles of eight of them in response to phytohormones and abiotic stresses. Our results indicated that expression of the SNF2 genes was affected by auxin, gibberellin, cytokinin, abscisic acid, ethylene, and some abiotic stresses such as heat, chilling, darkness, drought and salinity. It suggests that, like Arabidopsis SNF2s, rice SNF2 proteins may function in phytohormone...

Heterologous expression of P5CS gene in chickpea enhances salt tolerance without affecting yield

S. Kiran Kumar Ghanti, K. G. Sujata, B. M. Vijay Kumar, N. Nataraja Karba, K. Janardhan Reddy, M. Srinath Rao, P. B. Kavi Kishor

Biologia plantarum 2011, 55:634 | DOI: 10.1007/s10535-011-0161-0

Vigna Δ¹-pyrroline-5-carboxylate synthetase (P5CS) cDNA was transferred to chickpea (Cicer arietinum L.) cultivar Annigeri via Agrobacterium tumefaciens mediated transformation. Following selection on hygromycin and regeneration, 60 hygromycin-resistant plants were recovered. Southern blot analysis of five fertile independent lines of T0 and T1 generation revealed single and multiple insertions of the transgene. RT-PCR and Western blot analysis of T0 and T1 progeny demonstrated that the P5CS gene is expressed and produced functional protein in chickpea. T1 transgenic lines accumulated higher amount...

Early stages of leaf development in has mutant of Arabidopsis thaliana

D. Janošević, B. Uzelac, D. Stojičić, Lj. Tubić, S. Budimir

Biologia plantarum 2011, 55:641 | DOI: 10.1007/s10535-011-0162-z

The elucidation of molecular mechanisms underlying the leaf development can be facilitated by the detailed anatomical study of leaf development mutants. We present an analysis of leaf anatomy and morphogenesis during early developmental stages in has mutant of Arabidopsis thaliana. The recessive has mutation affects a number of aspects in plant development, including the shape and size of both cotyledons and leaves. The earliest developmental observations suggest almost synchronous growth of the first two leaf primordia of has mutant. No significant disruption of the cell division pattern in the internal tissue is observed...

Auxin is involved in the regulation of leaf and root development by LAF1 under short day conditions

B. S. Park, W. G. Sang, J. T. Song, B. H. Lee, J. H. Kim, H. S. Seo

Biologia plantarum 2011, 55:647 | DOI: 10.1007/s10535-011-0163-y

LAF1 (Long after far-red radiation 1) is a R2R3 Myb transcription factor and a signal transducer of far-red radiation. To investigate the role of LAF1 in leaf and root development, the leaf growth and vein patterning in laf1 mutants under short day conditions were examined. The length of rosette leaves was reduced and the width of the midvein was increased in laf1 mutants compared to their wild-type (WT) counterparts. In addition, cell size and cell number were both decreased in the laf1 mutant in comparison to the WT plant. A comparative analysis of gene expression showed that the transcript levels of PIN and IAA...

Inducible and constitutive expression of HvCBF4 in rice leads to differential gene expression and drought tolerance

T. Lourenço, N. Saibo, R. Batista, C. Pinto Ricardo, M. M. Oliveira

Biologia plantarum 2011, 55:653 | DOI: 10.1007/s10535-011-0164-x

The effects of the ectopic expression of a barley transcription factor (HvCBF4) under the control of a constitutive (maize Ubi1) or a stress-inducible (Arabidopsis RD29A) promoter in the abiotic stress response in rice (Oryza sativa L.) was investigated. The transformed plants were analyzed both at molecular and physiological level and the AtRD29A::HvCBF4 plants were further analyzed using the GeneChip® rice genome array under control conditions. Only the plants constitutively expressing HvCBF4 have shown increased survival to drought stress, but not to cold or high-salinity. These plants have also shown...

Hormonal control of the outgrowth of axillary buds in Alstroemeria cultured in vitro

P. Pumisutapon, R. G. F. Visser, G. -J. De Klerk

Biologia plantarum 2011, 55:664 | DOI: 10.1007/s10535-011-0165-9

We study apical dominance in Alstroemeria, a plant with an architecture very different from the model species used in research on apical dominance. The standard explant was a rhizome with a tip and two vertically growing shoots from which the larger part had been excised leaving ca. 1 cm stem. The axillary buds that resumed growth were located at this 1-cm stem just above the rhizome. They were released by removal of the rhizome tip and the shoot tips. Replacement of excised tips by lanolin with indole-3-butyric acid (IBA) restored apical dominance. The auxin transport inhibitors 2,3,5-triiodobenzoic acid (TIBA) and N-1-napthylphthalamic...

Singlet oxygen as a signaling transducer for modulating artemisinin biosynthetic genes in Artemisia annua

Q. -P. Zeng, X. -M. Zeng, R. -Y. Yang, X. -Q. Yang

Biologia plantarum 2011, 55:669 | DOI: 10.1007/s10535-011-0166-8

Although crosstalk between cytosolic and plastidic terpenoid pathways has been validated in many plant species, we report here for the first time a striking elevation of the nucleus-encoded artemisinin biosynthesis relevant DBR2 mRNA following the incubation of plants with fosmidomycin (FM). FM decreased singlet oxygen (¹O₂) scavengers such as β-carotene and α-tocopherol and subsequently invoked ¹O₂ burst. The treatment of plants with fluridone (FD) neither decreased α-tocopherol content nor triggered ¹O₂ emission. In conclusion, FM can up-regulate ¹O₂-sensitive...

Effects of elevated CO₂ applied to potato roots on the anatomy and ultrastructure of leaves

Z. -P. Sun, T. -L. Li, Y. -L. Liu

Biologia plantarum 2011, 55:675 | DOI: 10.1007/s10535-011-0167-7

The root system of potato (Solanum tuberosum L. cv. Favorita) plants was treated with different O₂ and CO₂ concentrations for 35 d in aeroponic culture. Under 21 or 5 % O₂ in the root zones, the thickness of leaves and palisade parenchyma significantly increased at 3 600 μmol(CO₂) mol^-1 in the root zone, compared with CO₂ concentration 380 μmol mol^-1 or low CO₂ concentration (100 μmol mol^-1). In addition, smaller cells of palisade tissue, more intercellular air spaces and partially two layers of palisade cells were observed in the leaves...

Boron-aluminum interactions affect organic acid metabolism more in leaves than in roots of Citrus grandis seedlings

N. Tang, H. -X. Jiang, L. -T. Yang, Q. Li, G. -H. Yang, L. -S. Chen

Biologia plantarum 2011, 55:681 | DOI: 10.1007/s10535-011-0168-6

Sour pummelo (Citrus grandis) seedlings were irrigated with nutrient solution containing four boron concentrations (i.e., 2.5, 10, 25 and 50 μM H₃BO₃) and two aluminum concentrations [i.e., 0 (-Al) and 1.2 mM AlCl₃ . 6 H₂O (+Al)]. It was found that B did not affect, but Al increased, the Al content in the roots. The Al and citrate contents in the -Al leaves either did not change or slightly increased with increasing B concentration. On the other hand, the Al and citrate contents in the +Al leaves rapidly decreased as B concentration increased from 2.5 to 50 μM, then decreased at...

Construction and functional analysis of pathogen-inducible synthetic promoters in Brassica napus

F. Shokouhifar, M. R. Zamani, M. Motallebi, A. Mousavi, M. A. Malboobi

Biologia plantarum 2011, 55:689 | DOI: 10.1007/s10535-011-0169-5

In this study, we selected two known pathogen-inducible cis-acting elements, F and E17, to construct synthetic pathogen-inducible promoters for analysis in transformed canola (Brassica napus L.). The synthetic promoter approach was used, which involved the insertion of dimers and combining two cis-acting elements (E17 and F) upstream of the minimal CaMV 35S promoter. Canola plants were transformed by three constructs, pGEE, pGFF, pGFFEE containing synthetic promoters (SP), SP-EE, SP-FF and SP-FFEE, respectively. Analyses of histochemical and fluorometric GUS expression indicated that synthetic promoters responded to fungal elicitors...

Molecular characterization of a gene induced during wheat hypersensitive reaction to stripe rust

G. Zhang, Y. -M. Li, Y. -F. Sun, J. -M. Wang, B. Liu, J. Zhao, J. Guo, L. -L. Huang, X. -M. Chen, Z. -S. Kang

Biologia plantarum 2011, 55:696 | DOI: 10.1007/s10535-011-0170-z

A novel gene induced during hypersensitive reaction (HIR) in wheat was identified using in silico cloning and designated as TaHIR2. The TaHIR2 gene was deduced to encode a 284-amino acid protein, whose molecular mass and isoelectric point (pI) were 31.05 kD and 5.18, respectively. Amino acid sequence analysis demonstrated the presence of stomatins, prohibitin, flotillins, HflK/C (SPFH) domain and prohibitin homologue for the TaHIR2 protein. Phylogenetic analysis of 13 HIR genes from different monocots indicated that TaHIR2 was highly homologous to HvHIR2. Transient expression analysis using particle-mediated bombardment...

Reviews

An insight into the drought stress induced alterations in plants

G. Thapa, M. Dey, L. Sahoo, S. K. Panda

Biologia plantarum 2011, 55:603 | DOI: 10.1007/s10535-011-0158-8

Plants are subjected to several abiotic stresses that adversely affect growth, metabolism and yield. The dynamic research in plant genetics complemented by genome sequencing has opened up avenues to address multiple problems caused by abiotic stresses. Though many drought-induced genes have been phytoengineered in a wide range of plants, the drought signal transduction pathways, and the alteration of plant sensing and signaling systems to adverse environments still remain an intriguing subject for comprehensive investigation. To impart enhanced drought tolerance in plants, a thorough perception of physiological, biochemical and gene regulatory networks...

Brief Communications

Callus sieving is effective in improving synchronization and frequency of somatic embryogenesis in Citrus sinensis

J. M. M. Souza, M. L. Tomaz, S. C. C. Arruda, C. G. B. Demétrio, W. N. Venables, A. P. Martinelli

Biologia plantarum 2011, 55:703 | DOI: 10.1007/s10535-011-0171-y

Somatic embryogenesis has been obtained in many citrus cultivars. However, culture synchronization is yet to be achieved and in the present work we evaluate the effect of desiccation, cold and size of cell clusters on embryo production efficiency from callus cultures of Citrus sinensis L. Osbeck, cv. Valencia. The results showed that sieving was effective in promoting somatic embryo synchronization, whether or not it was followed by cold or desiccation treatments. Histological and histochemical analyses are presented to characterize the structure of cell aggregates and protein accumulation.

Development of thirty new polymorphic microsatellite primers for Paeonia suffruticosa

X. -G. Hou, D. -L. Guo, S. -P. Cheng, J. -Y. Zhang

Biologia plantarum 2011, 55:708 | DOI: 10.1007/s10535-011-0172-x

Four new microsatellite primer pairs were developed in tree peony (Paeonia suffruticosa) based on the database mining and other twenty-six primer pairs by fast isolation by AFLP of sequences containing repeats (FIASCO) method. The polymorphism of each locus was further evaluated in 40 individuals of one population plus 5 tree peony related species. The number of alleles per locus ranged from 3 to 7 and the expected (H_e) and observed (H_o) heterozygosity at each locus ranged from 0.42 to 0.78 and 0.28 to 0.59, respectively. These microsatellite markers will be useful for investigating genetic diversity and studies of population...

Induction of sucrose synthase in the phloem of phytoplasma infected maize

J. Brzin, N. Petrovič, M. Ravnikar, M. Kovač

Biologia plantarum 2011, 55:711 | DOI: 10.1007/s10535-011-0173-9

In this study, we have analyzed the expression of the low oxygen inducible sucrose synthase isozyme SH1 (SUS-SH1) in the phloem of maize (Zea mays L.) infected with maize bushy stunt phytoplasma. Immunolocalization and Western blot analysis revealed several fold induction of SUS-SH1 in companion cells of phytoplasma inhabited phloem of leaf sheaths and stems. The results imply higher rates of sucrose metabolism and intensified hypoxia in the phloem.

Guard cells on adaxial and abaxial epidermes of Erythrina corallodendron sepals

B. Huang, Y. Wang, S. Huang, S. Ma

Biologia plantarum 2011, 55:716 | DOI: 10.1007/s10535-011-0174-8

This study investigated guard cells on the adaxial and the abaxial epidermes during Erythrina corallodendron sepal development. On the adaxial epidermis, the morphology of guard cells was highly variable and changes in aperture induced by abscisic acid (ABA) were observed in 9.1 % stomata, while on the abaxial epidermis 86.7 % stomata responded to ABA. On the adaxial epidermis, stomata did not close even when guard cell pressure potential was reduced to zero by plasmolysis, even if fluorescein diacetate revealed that guard cells were alive. It was concluded that guard cells on the adaxial and the abaxial epidermes of sepals sensed environmental...

Heat tolerance in rice mutants is associated with reduced accumulation of reactive oxygen species

M. Panigrahy, S. Neelamraju, D. Nageswara Rao, R. Ramanan

Biologia plantarum 2011, 55:721 | DOI: 10.1007/s10535-011-0175-7

Four mutants induced by ethylmethane sulphonate (N22-H-dgl56, N22-H-dgl101, N22-H-dgl162 and N22-H-dgl219) with conspicuous dark green leaves were identified in the drought and heat-tolerant rice cultivar Nagina22 (N22), when screened under prolonged drought and heat conditions in field. During dark-induced senescence, these mutants maintained higher chlorophyll and carotenoid contents, and photochemical efficiency of photosystem 2 in comparison with N22. Following heat treatment, these mutants accumulated less reactive oxygen species (assayed by histochemical staining for H₂O₂ and superoxide radicals)...

Phenolic compounds in apple leaves after infection with apple scab

M. Mikulic Petkovsek, A. Slatnar, F. Stampar, R. Veberic

Biologia plantarum 2011, 55:725 | DOI: 10.1007/s10535-011-0176-6

Leaves of the scab-susceptible apple (Malus domestica) cultivar Golden Delicious were harvested from May to August 2008 and 2009. Some leaves were healthy and some infected with fungus Venturia inaequalis. The phenolic compounds were analysed in healthy leaves, infected leaves and in the scab spot tissue. In comparison to healthy leaves, the infected leaves showed higher contents of hydroxycinnamic acid, flavanols and phloridzin, while lower contents on procyanidins, quercetins and phloretin. The total amount of phenolic compounds in the infected tissue was 10 to 20 % higher than in the healthy leaves. Accumulation of phenolic compounds...

Morphological and histological changes during the somatic embryogenesis of mangosteen

M. Elviana, E. R. Rohani, I. Ismanizan, M. N. Normah

Biologia plantarum 2011, 55:731 | DOI: 10.1007/s10535-011-0177-5

Induction of somatic embryogenesis in leaf explants from young mangosteen seedlings using different concentrations and combinations of 6-benzylaminopurine (BAP) and thidiazuron (TDZ) was investigated. The best medium inducing the formation of globular structures (40 %) was Murashige and Skoog medium with 0.7 mg dm^-3 BAP and 0.7 mg dm^-3 TDZ. For their further development, subculturing onto different maturation media was carried out, but these globular structures did not develop futher stages of somatic embryogenesis. However, they developed shoots after 90 d of culture on the original medium. Morphological and histological analyses...

The effect of exogenously applied nitric oxide on photosynthesis and antioxidant activity in heat stressed chrysanthemum

W. Yang, Y. Sun, S. Chen, J. Jiang, F. Chen, W. Fang, Z. Liu

Biologia plantarum 2011, 55:737 | DOI: 10.1007/s10535-011-0178-4

The effect of exogenously applied nitric oxide on the heat tolerance of Chrysanthemum morifolium was investigated by applying the NO donor sodium nitroprusside (SNP). We found that the SNP partially alleviated the heat stress by slowing down the reduction of photosynthetic pigment content and net photosynthetic rate. SNP treatment also lowered the increase in the non-photochemical quenching of fluorescence and malondialdehyde content and maintained higher activities of superoxide dismutase, peroxidase, catalase and ascorbate peroxidase.

NADPH oxidase as the source of ROS produced under waterlogging in roots of mung bean

R. K. Sairam, K. Dharmar, V. Chinnusamy, S. Lekshmy, R. Joshi, P. Bhattacharya

Biologia plantarum 2011, 55:741 | DOI: 10.1007/s10535-011-0179-3

The objective of this study was to examine the role of NADPH oxidase on superoxide radical production under waterlogging in mung bean (Vigna radiata) cvs. T 44 (tolerant) and Pusa Baisakhi (PB) (susceptible), and wild species Vigna luteola. Two days of waterlogging caused decline in superoxide radical (O₂ ^.-) contents in all the genotypes, however, further waterlogging up to 8 d caused significant increase in O₂ ^.- contents. In control and revived plants O₂ ^.- contents were higher in PB, while under waterlogging stress T 44 and V. luteola showed greater increases...

Effects of high temperature and low pH on photosystem 2 photochemistry in spinach thylakoid membranes

S. Mathur, P. Singh, P. Mehta, A. Jajoo

Biologia plantarum 2011, 55:747 | DOI: 10.1007/s10535-011-0180-x

The effects of temperature (25-45 °C) and pH (7.5-5.5) on photosystem (PS) 2 was studied in spinach (Spinacia oleracea L.) thylakoid membranes using chlorophyll a fluorescence induction kinetics. In high temperature and low pH treated thylakoid membranes a decline in the variable to maximum fluorescence ratio (F_v/F_m) and PS 2 electron transport rate were observed. More stacking in thylakoid membranes, studied by digitonin fractionation method, was observed at low pH, while the degree of unstacking increased under high temperature conditions. We conclude that the change in pH does not significantly affect the donor/acceptor...

Microtubule organization during successive microsporogenesis in Allium cepa and simultaneous cytokinesis in Nicotiana tabacum

Y. N. Zhang, D. M. Wei, Y. Y. Song, L. Chen, X. Y. Zhu, H. Q. Tian

Biologia plantarum 2011, 55:752 | DOI: 10.1007/s10535-011-0181-9

Microtubule cytoskeleton organization during microspore mother cell (MMC) meiosis in Allium cepa L. and microsporogenesis in Nicotiana tabacum L. was examined. The MMC microtubules (MTs) were short and well dispersed in the cytoplasm of both taxa. As the MMCs of both species entered metaphase of meiosis I, the MTs constructed a spindle that facilitated the chromosomes to orient in the meridian plane. At anaphase of meiosis I, the spindle MTs differentiated into two types: one MT type became short, pulled the chromosomes toward the two poles, and was designated as centromere MTs; the second type of MT connected the two poles, and was designated...

Cross talk between phytohormones in the regulation of flower induction in Pharbitis nil

E. Wilmowicz, K. Frankowski, P. Glazińska, J. Kęsy, W. Wojciechowski, J. Kopcewicz

Biologia plantarum 2011, 55:757 | DOI: 10.1007/s10535-011-0182-8

Application of gibberellic acid (GA₃) on the cotyledons of 5-d-old Pharbitis nil reversed the inhibitory effect of both abscisic acid (ABA) and ethylene on flowering. Application of GA₃ slightly decreased ethylene production and did not affect the endogenous ABA content in the cotyledons during the night. However, it reversed the stimulating effect of ABA on ethylene production.

Development and evaluation of expressed sequence tag-derived microsatellite markers for hop genotyping

J. Patzak, J. Matoušek

Biologia plantarum 2011, 55:761 | DOI: 10.1007/s10535-011-0183-7

The use of expressed sequence tag-simple sequence repeat (EST-SSR) markers might reflect the better relationship among species or cultivars than markers previously used. The first set of 30 EST-SSR was developed in hop (Humulus lupulus L.). They represent 25 gene loci with total of 1268 EST sequences. They were used for characterization of 11 hop samples and cross-amplification in Humulus japonicus Sieb. et Zucc. The number of alleles per locus ranged from two to nine. The observed and expected heterozygosities ranged from 0.182 to 0.956 and from 0.233 to 0.775, respectively. We used EST-SSR markers for cluster analysis of hop...

Effect of transient accumulation of anthocyanin on leaf development and photoprotection of Fagopyrum dibotrys mutant

J. -X. Lan, A. -L. Li, C. -X. Chen

Biologia plantarum 2011, 55:766 | DOI: 10.1007/s10535-011-0184-6

Changes in pigments contents, leaf area, leaf dry mass per unit area (LMA), photosynthetic rate and chlorophyll a fluorescence were investigated in developing leaves of Fagopyrum dibotrys Hara. mutant. Anthocyanins transiently accumulate below the upper epidermis during leaf ontogeny of this mutant. Red leaves possessed lower Chl content, LMA, photosynthetic rate and apparent carboxylation efficiency than green leaves. However, content of anthocyanins declined and above mentioned parameters increased during further leaf development. In both red and green leaves, chronic photoinhibition did not take place according to variable to maximum...

Adventitious root system reduces lead uptake and oxidative stress in sunflower seedlings

J. Strubińska, A. Hanaka

Biologia plantarum 2011, 55:771 | DOI: 10.1007/s10535-011-0185-5

In this work, the effect of lead on sunflower seedlings with two root system types: primary - formed from embryonic tissues and adventitious - originating from hypocotyl after cutting off primary roots was investigated. The seedlings were subjected to Pb(NO₃)₂ in doses: 0, 0.5, 2.5, 5 and 20 mg(Pb) dm^-3 for a week. Lead accumulation, seedling length and mass as well as selected parameters representative of oxidative damage (malondialdehyde) and protection (superoxide dismutase and glutathione) were used to compare stress response of plants. The comparison showed significant differences between plants with different...

Effect of low boron supply in turnip plants under drought stress

R. Hajiboland, F. Farhanghi

Biologia plantarum 2011, 55:775 | DOI: 10.1007/s10535-011-0186-4

Turnip (Brassica rapa L.) plants were grown in Perlite with low (< 2.5 μM) or adequate (25 μM) boron supply under well-watered and drought conditions for 12 weeks. Dry mass of leaves and roots was reduced under drought by about 61 and 56 % in plants supplied adequately with B, while up to 84 and 74 % under B starvation. Drought reduced B content by about 70 and 82 % for B-sufficient and B-deficient plants, respectively. According to the chlorophyll fluorescence parameters, the photosynthesis processes conserved their normal activities under low B supply in well-watered plants, while a serious damage to photosystem 2 occurred...

Catechin promotes growth of Arabidopsis thaliana with concomitant changes in vascular system, photosynthesis and hormone content

A. Rani, S. Kumar Vats, M. Sharma, S. Kumar

Biologia plantarum 2011, 55:779 | DOI: 10.1007/s10535-011-0187-3

Catechin is associated with several functions in animal and plant systems, with little information available regarding its role in plant growth. Low concentrations of catechin (50 and 100 μM) were found to enhance length of primary and lateral roots, number of lateral roots, fresh and dry masses of shoots and roots, leaf area, water potential of leaf and root tissues, the number of vascular bundles in the inflorescence, and leaf thickness in Arabidopsis thaliana ecotype Col-0. A significant increase in net photosynthetic rate, stomatal conductance and concentration of indole-3-acetic acid was also observed in catechin treated plants.

Effects of hypobaric growth conditions on morphogenic potential and antioxidative enzyme activities in Saussurea involucrata

B. Guo, B. H. Abbasi, Y. H. Wei

Biologia plantarum 2011, 55:783 | DOI: 10.1007/s10535-011-0188-2

Effects of reduced atmospheric pressure on morphogenic potential and antioxidative enzyme activities in regenerated tissues of Saussurea involucrata were evaluated. Leaf explants were cultured at atmospheric pressure 30, 60 or 101 kPa on Murashige and Skoog (MS) medium with several plant growth regulators (PGRs). Oxygen and carbon dioxide partial pressures were maintained at 21 and 0.038 kPa, respectively. At 60 kPa, 12 shoots per explant were recorded, which was 1.5 and 2.1-folds higher than at 101 and 30 kPa, respectively. A shooting frequency of 80 % was observed at 60 and 101 kPa. Rooted plantlets were obtained on MS medium with indoleacetic...

Paraquat pretreatment alters antioxidant enzyme activity and protects chloroplast ultrastructure in heat-stressed cucumber leaves

Y. Gao, Y. -K. Guo, A. -H. Dai, W. -J. Sun, J. -G. Bai

Biologia plantarum 2011, 55:788 | DOI: 10.1007/s10535-011-0189-1

Cucumis sativus L. seedlings were pretreated 1 h with 10 μM paraquat (PQ) and then were subjected to normal (25/18 °C) or elevated (42/38 °C) temperature to investigate whether PQ can protect plants against heat stress. Heat stress inhibited fresh and dry masses of the second leaf, root dry mass and shoot fresh mass. In leaves, the stress disintegrated membranes of 84.97 % chloroplasts and elevated contents of malondialdehyde, superoxide radical and hydrogen peroxide. In contrast, PQ pretreatment altered antioxidant activities in leaves, even after PQ was rinsed off before seedlings were exposed to different temperatures. Under heat stress,...

Hexanoic acid 2-(diethylamino)ethyl ester enhances chilling tolerance in strawberry seedlings by impact on photosynthesis and antioxidants

X. -J. Fu, A. S. Maimaiti, H. -M. Mou, Q. Yang, G. -J. Liu

Biologia plantarum 2011, 55:793 | DOI: 10.1007/s10535-011-0190-8

Strawberry (Fragaria ananassa Duch.) seedlings were pretreated with hexanoic acid 2-(diethylamino)ethyl ester (DA-6) in concentrations of 0, 10, 20 and 40 mg dm^-3 and then subjected to chilling and rewarming. The effects of applied DA-6 on the generation of reactive oxygen species (O₂ ^-, H₂O₂), lipid peroxidation, proline accumulation and photosynthesis were evaluated. Pretreatment with DA-6 alleviated the inhibition of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activities caused by chilling stress thus reducing O₂ ^- and H₂O₂...

Callus induction and plant regeneration from immature embryos of Brachypodium distachyon with different chromosome numbers

R. Hammami, A. Cuadrado, E. Friero, N. Jouve, C. Soler, J. M. González

Biologia plantarum 2011, 55:797 | DOI: 10.1007/s10535-011-0191-7

The paper reports the in vitro cultivation of two commercial lines and 23 wild populations (with 10, 20 and 30 chromosomes) of Brachypodium distachyon. Callus induction was assayed on Murashige and Skoog medium containing 1 mg dm^-3 2,4-dichlorophenoxyacetic acid (2,4-D) with 30 g dm^-3 of sucrose (MSs) or maltose (MSm). No significant differences were seen between the two media with respect to callus induction. Calli were transferred to MSm medium without 2,4-D but containing 0.1 mg dm^-3 of 6-benzylaminopurine for plant regeneration. The plant regeneration response was very variable depending on the original...