Anthocyanin accumulation and expression pattern of anthocyanin biosynthesis genes in developing wheat coleoptiles

N. Ahmed, M. Maekawa, K. Noda

Biologia plantarum 2009, 53:223-228 | DOI: 10.1007/s10535-009-0043-x

Anthocyanin accumulation and expression pattern of anthocyanin biosynthesis genes were investigated in developing coleoptiles of wheat (Triticum aestivum L.). In epidermal cell layers of the growing coleoptiles of cv. Hope, anthocyanins started to accumulate between day 2 and 3 after germination, reached their maximum on day 6 and then decreased while another cultivar, Chinese Spring (CS) did not accumulate anthocyanin pigments. None of the six anthocyanin biosynthesis genes was upregulated in coleoptiles of both cvs. grown in the dark, whereas all genes were activated by light in coleoptiles of cv. Hope. Transcript levels of all the six genes...

Photosynthetic parameters and leaf water potential of five common bean genotypes under mild water deficit

M. G. Santos, R. V. Ribeiro, E. C. Machado, C. Pimentel

Biologia plantarum 2009, 53:229-236 | DOI: 10.1007/s10535-009-0044-9

The leaf water potential, gas exchange and chlorophyll fluorescence were evaluated in five common bean (Phaseolus vulgaris) genotypes A222, A320, BAT477, Carioca and Ouro Negro subjected to moderate water deficit. At the maximum water deficit (10 d of water withholding), the leaf water potential of genotypes A320 and A222 was higher (-0.35 and -0.50 MPa) when compared to the other genotypes (-0.67 to -0.77 MPa). The stomatal conductance and net photosynthetic rate were significantly reduced in all genotypes due to the water deficit. The greater reduction in stomatal conductance of A320 under drought resulted in high intrinsic water use efficiency....

Growth, lipid peroxidation and photosynthesis in two tall fescue cultivars differing in heat tolerance

J. Z. Wang, L. J. Cui, Y. Wang, J. L. Li

Biologia plantarum 2009, 53:237-242 | DOI: 10.1007/s10535-009-0045-8

Seedlings (70-d-old) of two tall fescue (Festuca arundinacea Schreb.) genotypes, heat-tolerant Jaguar 3 and heat-sensitive TF 66, were exposed to a high temperature stress of 35/30 °C (day/night) for 20 d and both light-saturated and CO₂-saturated leaf stomatal conductance decreased, especially in TF 66. Higher reductions of quantum efficiency, carboxylation efficiency and maximum photochemical efficiency of photosystem 2 in dark adapted leaves (measured as F_v/F_m) occurred in TF 66 than in Jaguar 3. High temperature stress increased photorespiration in the two plants, but more in TF 66. Moreover, high temperature...

Salt stress effects on growth, pigments, proteins and lipid peroxidation in Salicornia persica and S. europaea

M. Aghaleh, V. Niknam, H. Ebrahimzadeh, K. Razavi

Biologia plantarum 2009, 53:243-248 | DOI: 10.1007/s10535-009-0046-7

The effects of NaCl stress on growth, water status, contents of protein, proline, malondialdehyde (MDA), various sugars and photosynthetic pigments were investigated in seedlings of Salicornia persica and S. europaea grown in vitro. Seeds were germinated under NaCl (0, 100, 200, 300, 400, 500 and 600 mM) on Murashige and Skoog medium for 45 d. The shoot growth of both species increased under low NaCl concentration (100 mM) and then decreased with increasing NaCl concentrations. In contrast to S. persica, root length in S. europaea reduced steadily with an increase in salinity. Proline content in S. persica...

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 2009, 53:249-256 | 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...

The influence of cold acclimation on antioxidative enzymes and antioxidants in sensitive and tolerant barley cultivars

F. Dai, Y. Huang, M. Zhou, G. Zhang

Biologia plantarum 2009, 53:257-262 | DOI: 10.1007/s10535-009-0048-5

In order to better understand the role of cold acclimation in alleviating freezing injury, two barley cultivars with different cold tolerance, i.e. a sensitive cv. Chumai 1 and a tolerant cv. Mo 103, were used. The freezing treatment increased leaf soluble protein content more in the tolerant cultivar than in the sensitive one. Cold acclimation increased H₂O₂ content of the two cultivars during freezing treatment, especially in Mo 103. Glutathione and ascorbate contents during freezing and recovery were significantly higher in cold-acclimated plants than in non-acclimated ones. Activities of peroxidase, ascorbate peroxidase...

Aerenchyma formation in maize roots

Z. Lenochová, A. Soukup, O. Votrubová

Biologia plantarum 2009, 53:263-270 | DOI: 10.1007/s10535-009-0049-4

Maize (Zea mays L.) is generally considered to be a plant with aerenchyma formation inducible by environmental conditions. In our study, young maize plants, cultivated in various ways in order to minimise the stressing effect of hypoxia, flooding, mechanical impedance or nutrient starvation, were examined for the presence of aerenchyma in their primary roots. The area of aerenchyma in the root cortex was correlated with the root length. Although 12 different maize accessions were used, no plants without aerenchyma were acquired until an ethylene synthesis inhibitor was employed. Using an ACC-synthase inhibitor, it was confirmed that the aerenchyma...

A new tip homolog, ShTIP, from Salicornia shows a different involvement in salt stress compared to that of TIP from Arabidopsis

N. Ermawati, Y. S. Liang, J.-Y. Cha, D. Shin, M. H. Jung, J. J. Lee, B.-H. Lee, C.-D. Han, K. H. Lee, D. Son

Biologia plantarum 2009, 53:271-277 | DOI: 10.1007/s10535-009-0050-y

To obtain an insight into the comprehensive molecular characteristics of the salt tolerance mechanism, we performed a screening for salt inducible genes in a halophytic plant, Salicornia herbacea, using mRNA differential display. A comparative analysis of gene expression in Salicornia grown in control and salt-stressed conditions led to the detection of a gene that was induced by salt. Both sequence analysis and a subsequent database search revealed that this gene was highly homologous to tonoplast intrinsic proteins (TIPs) from a variety of plant species. This gene, designated as ShTIP, is 1014 bp in size and contains a coding...

The mitigating role of environmental factors in seedling injury and chill-dependent depression of catalase activity in maize leaves

R. Bączek-Kwinta, J. Kościelniak

Biologia plantarum 2009, 53:278-284 | DOI: 10.1007/s10535-009-0051-x

In pot experiments performed on maize seedlings chilled at 5 °C, leaf injury was diminished by the application of elevated temperature (1 or 5 h at 15 or 20°C, "warm breaks" treatment) in a dose-dependent manner. The lower the injury count, the higher the catalase (CAT) activity. In a separate experiment, the application of 100 % relative humidity also protected the plants from chilling injury and water loss, increased their gas exchange and variable to maximum chlorophyll fluorescence ratio (F_v/F_m), but did not influence CAT activity. Another protective environmental factor, elevated atmospheric CO₂ concentration [700...

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

T. Mahmood, A. Jan, S. Komatsu

Biologia plantarum 2009, 53:285-293 | 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,...

Dark and light green tissues of tobacco leaves systemically infected with tobacco mosaic virus

O. L. Burundukova, M. V. Sapotsky, A. V. Kochetov, E. A. Trifonova, V. I. Malinovsky

Biologia plantarum 2009, 53:294-300 | DOI: 10.1007/s10535-009-0053-8

There are significant changes in the structure of the upper tobacco (Nicotiana tabacum L.) leaves systemically infected with tobacco mosaic virus (TMV) especially in the light green tissue (LGT). Dark green areas (DGI) had intermediate status between healthy tissue and LGT. DGI contained significantly less infectious TMV and viral antigen than the LGT. The DGI, LGT and healthy tissues did not differ in the permeability of cell membranes and in the set of acidic pathogenesis-related (PR) proteins but the total content of PR-proteins in the healthy plants was higher than in the infected ones with the DGI being intermediate between healthy tissue...

Phenylalanine ammonia lyase genes in red clover: Expression in whole plants and in response to yeast fungal elicitor

M. L. Sullivan

Biologia plantarum 2009, 53:301-306 | DOI: 10.1007/s10535-009-0054-7

In red clover (Trifolium pratense L.) four unique cDNAs encoding phenylalanine ammonia lyase (PAL, EC 4.3.1.5) were identified (PAL1-4). PAL2-4 encode nearly identical proteins (> 97 %) that are only 89 % identical to that encoded by PAL1. Under normal growing conditions, in young leaves and flowers PAL1 mRNA accumulates to higher levels than that of PAL2-4 whereas in mature leaves and stems, mRNA levels are similar for PAL1 and PAL2-4. Treatment of red clover seedlings with yeast elicitor preparation results in an approximately six-fold induction of PAL2-4 transcripts within 1 h of treatment but only a modest induction of PAL1 transcripts....

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

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

Biologia plantarum 2009, 53:201-212 | 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...

Interactions of lichens with heavy metals

M. Bačkor, S. Loppi

Biologia plantarum 2009, 53:214-222 | DOI: 10.1007/s10535-009-0042-y

Recent developments in knowledge about the interactions between lichens and heavy metals at different levels, from populations to cells and from ecology to molecular biology are reviewed. Sources of heavy metals, mechanisms of heavy metal accumulation and detoxification by lichens are discussed. Special emphasis is placed on ultrastructural changes as well as physiological parameters such as membrane integrity, pigment composition, chlorophyll a fluorescence, photosynthesis, respiration, contents of ATP, amino acids, ergosterol, ethylene, non-protein thiols, activity of antioxidant enzymes and expression of stress proteins.

Frowine, S.A.: Moth orchid. The complete guide to Phalaenopsis

I. Babůrek

Biologia plantarum 2009, 53:372 | DOI: 10.1007/s10535-009-0040-0

Bowsher, C., Steer, M., Tobin, A.: Plant Biochemistry

J. Pospíšilová

Biologia plantarum 2009, 53:400 | DOI: 10.1007/s10535-009-0076-1

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

J. Pospíšilová

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

Cotton somatic embryo morphology affects its conversion to plant

S. S. Hussain, A. Q. Rao, T. Husnain, S. Riazuddin

Biologia plantarum 2009, 53:307-311 | DOI: 10.1007/s10535-009-0055-6

Somatic embryos differentiated from hypocotyl explant in cotton (Gossypium hirsutum L.) exhibited very divergent morphologies. Six different types of somatic embryos based on cotyledon development were observed. The growth hormones (2,4-dichlorophenoxyacetic acid and kinetin) used in induction and maintenance media did not affect embryo rooting and germination. The 95 % conversion of normal embryos (with two cotyledons) was achieved, while an overall conversion was only 38 %. Horn shaped embryos failed to exhibit shoot growth. Poorly developed apical meristems were responsible for lower conversion percentages in some of embryo classes. However,...

High frequency plant regeneration from the cotyledonary node of common bean

W. Dang, Z. M. Wei

Biologia plantarum 2009, 53:312-316 | DOI: 10.1007/s10535-009-0056-5

An efficient regeneration system for Phaseolus vulgaris was developed from mature seeds germinated on Murashige and Skoog (MS) medium supplemented with thidiazuron or N⁶-benzylaminopurine (BA) for 6 d. Using cotyledonary nodes, multiple buds were induced on the MS medium supplemented with 5.0 mg dm^-3 BA with the induction frequency 71.9 % after 4-week culture. The buds were then transferred onto shoot formation medium containing 1.0 mg dm^-3 BA, 0.1 mg dm^-3 gibberellic acid and 2.0 mg dm^-3 silver nitrate. The addition of AgNO₃ enhanced the frequency of the shoot formation from...

Genetic variability in the endemic Leucojum valentinum

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

Biologia plantarum 2009, 53:317-320 | 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.

Pre-treatment with H₂O₂ induces salt tolerance in Barley seedlings

I. S. Fedina, D. Nedeva, N. Çiçek

Biologia plantarum 2009, 53:321-324 | DOI: 10.1007/s10535-009-0058-3

Barley seedlings were pre-treated with 1 and 5 µM H₂O₂ for 2 d and then supplied with water or 150 mM NaCl for 4 and 7 d. Exogenous H₂O₂ alone had no effect on the proline, malondialdehyde (MDA) and H₂O₂ contents, decreased catalase (CAT) activity and had no effect on peroxidase (POX) activity. Three new superoxide dismutase (SOD) isoenzymes appeared in the leaves as a result of 1 µM H₂O₂ treatment. NaCl enhanced CAT and POX activity. SOD activity and isoenzyme patterns were changed due to H₂O₂ pre-treatment, NaCl stress and leaf...

In vitro direct organogenesis and regeneration of Medicago sativa

J. J. Li, Y.M. Wu, T. Wang, J. X. Liu

Biologia plantarum 2009, 53:325-328 | DOI: 10.1007/s10535-009-0059-2

A rapid and efficient plant regeneration protocol for a wide range of alfalfa genotypes was developed via direct organogenesis. Through a successive excision of the newly developed apical and axillary shoots, a lot of adventitious buds were directly induced from the cotyledonary nodes when hypocotyl of explants were vertically inserted into modified Murashige and Skoog (MS) medium supplemented with 0.025 mg dm^-3 thidiazuron (TDZ) and 3 mg dm^-3 AgNO₃. When the lower part of shoots excised from explants were immersed into the liquid medium with 1.0 mg dm^-3 α-naphthaleneacetic acid (NAA) for 2 min,...

Photosystem 2-activity and thylakoid membrane polypeptides of in vitro cultured chrysanthemum as affected by NaCl

D. M. Pandey, I. Choi, U.-D. Yeo

Biologia plantarum 2009, 53:329-333 | DOI: 10.1007/s10535-009-0060-9

Long-term (30 d) effects of 100, 200, 300, and 400 mM NaCl on photosystem 2 (PS 2)-mediated electron transport activity and content of D1 protein in the thylakoid membranes of chrysanthemum (Dendranthema grandiflorum) cultured in vitro at low irradiance 20 µmol(photon) m^-2 s^-1 were investigated. 100 mM NaCl increased contents of chlorophylls (Chl) a and b, carotenoids (Car; xanthophylls + carotenes), and the ratio of Chl a/b, and Car/Chl a+b. However, further increase in NaCl concentration led to the significant reduction in the contents of Chl a, and Chl b, and increase...

Effects of salicylic acid and salinity on apoplastic antioxidant enzymes in two wheat cultivars differing in salt tolerance

S. Mutlu, Ö. Atici, B. Nalbantoglu

Biologia plantarum 2009, 53:334-338 | DOI: 10.1007/s10535-009-0061-8

The effects of salicylic acid (SA) and salinity on the activity of apoplastic antioxidant enzymes were studied in the leaves of two wheat (Triticum aestivam L.) cultivars: salt-tolerant (Gerek-79) and salt-sensitive (Bezostaya). The leaves of 10-d-old seedlings grown at nutrient solution with 0 (control), 250 or 500 mM NaCl were sprayed with 0.01 or 0.1 mM SA. Then, the activities of catalase (CAT), peroxidase (POX) and superoxide dismutase (SOD) were determined in the fresh leaves obtained from 15-d-old seedlings. The NaCl applications increased CAT and SOD activities in both cultivars, compared to those of untreated control plants. In addition,...

Influence of elevated CO₂ and O₃ on IAA, IAA oxidase and peroxidase in the leaves of ginkgo trees

X.-M. Li, X.-Y. He, L.-H. Zhang, W. Chen, Q. Chen

Biologia plantarum 2009, 53:339-342 | DOI: 10.1007/s10535-009-0062-7

This study examined the impacts of elevated CO₂ or O₃ on indole-3-acetic acid (IAA) content, activities of IAA oxidase (IAAO) and peroxidase (POD) in Ginkgo biloba leaves. Plants grown in open-top chambers were exposed to ambient atmosphere (control; C), elevated CO₂ and elevated O₃ from 1 June to 30 September. An increase in IAA content and decrease in IAAO and POD activities were observed in plants exposed to elevated CO₂ compared with C. Elevated O₃ had no significant effect on IAA content and IAAO activity, but increased POD activity during the early days. When trees pre-exposed...

Genetic diversity assessment in greek Medicago truncatula genotypes using microsatellite markers

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

Biologia plantarum 2009, 53:343-346 | 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...

Micropropagation of Bixa orellana using phytohormones and triacontanol

R. Parimalan, P. Giridhar, H. B. Gururaj, G. A. Ravishankar

Biologia plantarum 2009, 53:347-350 | DOI: 10.1007/s10535-009-0064-5

An efficient micropropagation protocol for annatto (Bixa orellana L.) was achieved using nodal shoot tip explants. Shoot buds were obtained on the Murashige and Skoog (MS) medium supplemented with various concentrations and combinations of indole-3-acetic acid (IAA), N⁶-benzyladenine (BA) and triacontanol (TRIA). Maximum of 213 shoot buds along with 18 primary shoots were produced on MS medium containing 0.05 µM IAA, 8.87 µM BA, and 11.2 µM TRIA. The primary shoots elongated best on MS medium containing 6.66 µM BA and 2.45 µM indole-3-butyric acid (IBA). The regenerated shoots rooted best on MS medium...

Increase in isoprene and monoterpene emissions after re-watering of droughted Quercus ilex seedlings

J. Peñuelas, I. Filella, R. Seco, J. Llusià

Biologia plantarum 2009, 53:351-354 | DOI: 10.1007/s10535-009-0065-4

We followed the diurnal cycles of isoprenoid emissions from Quercus ilex seedlings under drought and after re-watering. We found that Quercus ilex, generally considered a non-isoprene emitter, also emitted isoprene although at low rates. The emission rates of isoprene reached 0.37 ± 0.02 nmol m^-2 s^-1 in controls, 0.15 ± 0.03 nmol m^-2 s^-1 under drought and 0.35 ± 0.04 nmol m^-2 s^-1 after re-watering, while emission rates of monoterpenes reached 11.0 ± 3.0, 7.0 ± 1.0 and 23.0 ± 5.0 nmol m^-2 s^-1, respectively....

Expression of Rhizobium pydA-pydB fusion gene in Nicotiana tabacum confers resistance to the toxic aromatic compound 3-hydroxy-4-pyridone

S. Jube, J. Awaya, D. Borthakur

Biologia plantarum 2009, 53:355-359 | DOI: 10.1007/s10535-009-0066-3

The toxic aromatic compound 3-hydroxy-4-pyridone (HP) is an intermediate in both synthesis and degradation of mimosine, which is produced by the tree legume Leucaena leucocephala. The L. leucocephala root-nodule symbiont Rhizobium TAL1145 contains a dioxygenase (pydA) and a hydrolase (pydB) gene that produce enzymes necessary for the degradation of HP. In order to coordinately express both genes in plant tissues under a single promoter, three different pydA-pydB fusion constructs (G0, G3, and G7) with varying glycine linkers between the two genes were developed. Prior to transferring the fusion constructs into...

In vitro organogenesis and plant regeneration from unpollinated ovary cultures of Azadirachta indica

P. Srivastava, M. Singh, P. Mathur, R. Chaturvedi

Biologia plantarum 2009, 53:360-364 | DOI: 10.1007/s10535-009-0067-2

A novel method of organogenesis in neem (Azadirachta indica A. Juss.) from unfertilized ovaries is described. The Murashige and Skoog's (MS) medium with 9 % sucrose, 1 µM 2,4-dichlorophenoxyacetic acid (2,4-D) and 5 µM 6-benzylaminopurine (BAP) was the best for callus induction from unfertilized ovaries. However, further proliferation of callus occurred better on MS medium supplemented with 0.5 µM 2,4-D either alone or in combination with 4.5 µM kinetin. Maximum shoot regeneration (78 %) was observed when calli, induced from ovaries of 4 mm size flower buds and proliferating on MS + 0.5 µM 2,4-D, were subcultured...

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 2009, 53:365-368 | 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.

Cd-induced system of defence in the garlic root meristematic cells

W. S. Jiang, D. H. Liu, P. Xu

Biologia plantarum 2009, 53:369-372 | DOI: 10.1007/s10535-009-0069-0

Studies on cadmium effects in the root meristematic cells of Allium sativum L. were carried out using electron microscopy in order to explain the possible mechanisms of garlic seedlings' tolerance to Cd stress. Seedlings were treated with 0.01, 0.10 and 1.00 mM CdCl₂ solutions for 0.5, 1, 2, 4, 8, 10, 12, 24 and 48 h, respectively. The results indicated that cell walls, plasma membrane and main organelles actively participated in Cd detoxification and tolerance at low Cd concentrations. Once excessive Cd ions entered the cytosol, a defence mechanism becomes activated, protecting the cells against cadmium toxicity. However, under high...

Ultrastructural responses of the desiccation tolerant plants Xerophyta viscosa and X. retinervis to dehydration and rehydration

A. Bhatt, Y. Naidoo, S. Gairola, A. Nicholas

Biologia plantarum 2009, 53:373-377 | DOI: 10.1007/s10535-009-0070-7

This paper compares the changes in water content, chlorophyll a fluorescence and leaf ultrastructure during dehydration and rehydration in two desiccation tolerant plants Xerophyta viscosa and X. retinervis. Both species showed decreasing quantum efficiency of photosystem 2 (F_v/F_m) with decreasing water content. Extreme water loss observed after 25 d of dehydration resulted in considerable damage of leaf tissue ultrastructure. After rehydration, both species need several days to reconstitute their photosynthetic machinery.

Effects of phosphorus and chilling under low irradiance on photosynthesis and growth of tomato plants

Y. H. Zhou, J. X. Wu, L. J. Zhu, K. Shi, J. Q. Yu

Biologia plantarum 2009, 53:378-382 | DOI: 10.1007/s10535-009-0071-6

To determine the effects of phosphorus nutrition on chilling tolerance of photosynthetic apparatus, tomato (Lycopersicon esculentum Mill. cv. Kenfengxin 2002) plants were raised under different P contents and subjected to 7 d of chilling at 9/7 °C. After chilling (2 h or 7 d) plant growth, P content in tissue, gas exchange and chlorophyll fluorescence were measured. Decreasing P concentration [P] in the nutrient solution markedly reduced plant growth and the chilled plants exhibiting higher optimum [P] than the unchilled plants. Decreasing [P] significantly decreased light saturated net photosynthetic rate (P_Nsat), maximum carboxylation...

Somatic embryogenesis and plant regeneration in Cedrela fissilis

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

Biologia plantarum 2009, 53:383-386 | 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...

Cadmium effects on the organization of microtubular cytoskeleton in interphase and mitotic cells of Allium sativum

P. Xu, D. Liu, W. Jiang

Biologia plantarum 2009, 53:387-390 | DOI: 10.1007/s10535-009-0073-4

We have investigated the effects of cadmium on the microtubular (MT) cytoskeleton in the root tip cells of Allium sativum L. using indirect immunofluorescence microscopy. Cd affected the mechanisms controlling the organization of MT cytoskeleton, as well as tubulin assembly/disassembly processes. Cd induced the formation of abnormal MT arrays, consisting of discontinuous wavy MTs or short MT fragments at the cell periphery. Cadmium caused irregular nuclear disorder in cells where the MT organization and function was disturbed. Furthermore, with increased Cd concentration and duration of treatment the MTs depolymerized more severely, the frequency...

Photosynthetic and anatomic responses of peanut leaves to zinc stress

G. R. Shi, Q. S. Cai

Biologia plantarum 2009, 53:391-394 | DOI: 10.1007/s10535-009-0074-3

In this study, photosynthetic performance, pigment content, chlorophyll a fluorescence, and leaf anatomy in peanut (Arachis hypogaea) subjected to zinc (Zn) stress were investigated. Zn stress resulted in reduction of photosynthetic and transpiration rates, pigment contents and root biomass. Zn-induced xerophyte structure in peanut leaves (i.e. thick lamina, upper epidermis, and palisade mesophyll, as well as abundant and small stomata) also contributed to decreased transpiration rate and stomatal conductance. This in turn, partially contributed to the limitation of photosynthesis.

In vitro organogenesis of Citrus volkameriana and Citrus aurantium

E. C. R. Tavano, L. C. L. Stipp, F. R. Muniz, F. A. A. Mourão Filho, B. M. J. Mendes

Biologia plantarum 2009, 53:395-399 | DOI: 10.1007/s10535-009-0075-2

In vitro organogenesis of Citrus volkameriana and C. aurantium was studied considering three explant types: epicotyl segment, internodal segment, and hypocotyl segment with attached cotyledon fragment. The explants were cultured in medium according to Grosser and Gmitter (EME) supplemented with 0, 0.5, 1.0, 1.5, and 2.0 mg dm^{- 3} 6-benzyl-aminopurine (BAP), incubated firstly in darkness for 4 weeks, and then transferred to 16-h photoperiod for 2 weeks. Comparing epicotyl and internodal segments, a higher percentage of responsive explants and a higher number of shoots per explant were obtained with epicotyl segments, regardless...