Acta Physiologiae Plantarum

Appenroth, Klaus-J

doi: 10.1007/s11738-009-0455-4pmid: N/A

Plants do not have the ability to sense physical properties of metals, e.g. specific weight. The term “heavy metal” was defined mainly by the specific weight of metals. The definition was often connected with the expectation that the substance should be toxic. This definition is not acceptable and also inconsistent in use as already stressed in literature. However, in Plant Sciences, the term is so widely used that it is hardly possible to eliminate it. We suggest instead defining the term in a more unequivocal way. This should be done on the basis of the periodic system of elements. Here, we suggest introducing the following three subgroups forming the group of heavy metals for use in Plant Sciences. 1st subgroup: all transition elements except La and Ac (Transition metals). 2nd subgroup: rare earth elements, subdivided in the series of lanthanides and the series of actinides including La and Ac themselves (Rare earth metals). 3rd subgroup: a heterogenous group p-elements including the metal Bi, the amphoterous oxides forming elements Al, Ga, In, Tl, Sn, Pb, Sb and Po, and the metalloids Ge, As and Te. We suggest using the term “lead-group” for this 3rd subgroup of heavy metals as in Toxicology and Environmental Sciences, Pb is the most prominent representative of this group.

Yu, Haiqing; Zhang, Chun; Ding, Chunbang; Wang, Xiaoli; Zhang, Haiqin; Zhou, Yonghong

doi: 10.1007/s11738-009-0441-xpmid: N/A

Genomic constitutions of three taxa of Pseudoroegneria Á. Löve, P. geniculata, P. geniculata ssp. scythica, and P. geniculata ssp. pruinifera, were characterized using genomic in situ hybridization (GISH). The results indicated that ploidy level and genomic constitution in the three Pseudoroegneria taxa studied were as follows: P. geniculata (2n = 4x = 28; genomic formula StSt g ), P. geniculata ssp. scythica (2n = 4x = 28; genomic formula ESt), and P. geniculata ssp. pruinifera (2n = 6x = 42; genomic formula EESt). P. geniculata ssp. scythica and P. geniculata ssp. pruinifera should be transferred to Trichopyrum Á. Löve following Löve’s principles and treated as T. scythicum and T. pruiniferum, respectively.

Petrovská, B.; Salaj, T.; Moravčíková, J.; Libantová, J.; Salaj, Jan

doi: 10.1007/s11738-009-0442-9pmid: N/A

Flax suspension cultures have been established from the callus induced from the cotyledons, hypocotyls, and immature zygotic embryos (iZE). The growth of flax suspension culture (expressed as a sedimented cell volume) was compared in both conditioned (by liquid from embryogenic Pinus nigra suspension culture) and non-conditioned media. Conditioning of media significantly increased the growth of the cell lines of hypocotyl and iZE origin; however, it had no promotive effect on embryogenic response of these flax liquid cultures. Formation of embryo-like structures (ELS), confirmed also histologically, has only been found in the cell line derived from iZE and cultivated in non-conditioned MS medium supplemented with 1 mg l−1 2,4-D. The process of ELS formation in this cell line was accompanied by the expression of the protein(s) with chitinolytic activity and molecular weight approximately of 25 kDa. The relationship between the formation of ELS and secretion of chitinase(s) is discussed.

Islam, S.; Tammi, R.; Singla-Pareek, Sneh; Seraj, Zeba

doi: 10.1007/s11738-009-0443-8pmid: N/A

Rice yield is severely affected by high-salt concentration in the vicinity of the plant. In an effort to engineer rice for improved salt tolerance Agrobacterium-mediated transformation of rice cv. Binnatoa was accomplished with the Pennisetum glaucum vacuolar Na+/H+ antiporter gene (PgNHX1) under the constitutive CaMV35S promoter. For the molecular analysis of putative transgenic plants, PCR and RT-PCR were performed. Transgenic rice plants expressing PgNHX1 showed better physiological status and completed their life cycle by setting flowers and seeds in salt stress, while wild-type plants exhibited rapid chlorosis and growth inhibition. Moreover, transgenic rice plants produced higher grain yields than wild-type plants under salt stress. Assessment of the salinity tolerance of the transgenic plants at seedling and reproductive stages demonstrated the potential of PgNHX1 for imparting enhanced salt tolerance capabilities and improved yield.

Grąbkowska, Renata; Królicka, Aleksandra; Mielicki, Wojciech; Wielanek, Marzena; Wysokińska, Halina

doi: 10.1007/s11738-009-0445-6pmid: N/A

A genetic transformation method using Agrobacterium rhizogenes was developed for Harpagophytum procumbens. The influence of three factors on hairy root formation was tested: bacterial strains (A4 and ATCC 15834), various types of explants and acetosyringone (AS) (200 μM). The highest frequency of transformation (over 50% of explants forming roots at the infected sites after 6 weeks of culture on Lloyd and McCown (WP) medium) was achieved using a combination of nodal stem explants and A. rhizogenes strain A4. The addition of 200 μM AS to root induction medium was found to enhance hairy root induction but its effect varied depending on bacterial strain and explant type. Three of the most vigorously growing hairy root clones of H. procumbens were chosen and analyzed for accumulation of iridoid and phenylethanoid glycosides. The transgenic nature of these root clones was confirmed by PCR amplification; they were positive for rolB and rolC genes. Harpagoside, verbascoside and isoverbascoside were identified by HPLC and LC–ESI-MS as the major compounds from all analyzed hairy root clones. The Hp-3 root clone showed the higher harpagoside content (0.32 mg g−1 dry wt.) compared with other analyzed transformed and non-tuberized untransformed roots of H. procumbens. However, the level of the compound in the hairy root clone was lower than that detected in a sample of commercially available root tubers of H. procumbens. The Hp-3 root clone also produced high amounts of verbascoside and isoverbascoside (8.12 mg g−1 dry wt. and 9.97 mg g−1 dry wt., respectively) comparable to those found in root tubers.

Pinhatti, Amanda; Matos Nunes, Jéssica; Maurmann, Natasha; Rosa, Luís; Poser, Gilsane; Rech, Sandra

doi: 10.1007/s11738-009-0446-5pmid: N/A

The phenolic compound content of Hypericum ternum was investigated after micropropagation establishment and during acclimatization over the phenological development of the plant. Plantlets cultured in vitro on full Murashige and Skoog medium without growth regulators displayed higher phenolic compound yields, were acclimatized, and field grown. Production of total phenolic compounds as well as hyperoside, chlorogenic acid, quercitrin, guaijaverin, isoquercitrin, and uliginosin B were quantified at vegetative, flowering and fructification stages, and different plant organs (roots, stems, leaves and reproductive parts) showing that reproductive parts at flowering stage and the leaves at fructification stage were the main repository site of secondary metabolites, except for uliginosin B. The stems were the least accumulative organ, while the roots accumulated only hyperoside and uliginosin B. Moreover, the accumulation of most of the flavonoids and uliginosin B in acclimatized plants surpassed the levels found in the wild plant, warranting further research with the species.

Sorgonà, Agostino; Cacco, Giovanni; Dio, Lugi; Schmidt, Wolfgang; Perry, Paula; Abenavoli, Maria

doi: 10.1007/s11738-009-0447-4pmid: N/A

Spatial–temporal variation of the regulation and the kinetics of net nitrate (NO3 −) uptake rate (NNUR) along the tap root of Citrus aurantium L. were analysed. Suberin incrustation in the peripheral cell layers and plasma membrane (PM) H+-ATPase localisation, anatomical and physiological factors involved in NO3 − uptake were also investigated. The results clearly indicated a spatially uniform distribution of the regulation process, accompanied by a temporal heterogeneous pattern of the kinetics of NO3 − uptake along citrus tap root. In particular, kinetic analysis had a biphasic pattern, saturating (high affinity transport system) and linear (low affinity transport system), in response to increasing external NO3 − concentrations in each root region, where 200 μM NO3 − represented the threshold separating these two systems. Kinetic parameters, K m and V max, clearly indicated that apical segments reached the maximum value of induction before basal segments. Hence, the apical root zones, early exhibiting the maximum of potential capacity to absorb the NO3 −, could be considered more efficient than basal root segments for acquiring NO3 − from external solution. Suberin incrustations in the hypodermal cell layer, characterised by uniform fluorescence intensity among the root segments, could be responsible for the unchanged NNUR, while the PM H+-ATPase could explain the temporal pattern of NNUR.

Usha Rani, Pathipati; Jyothsna, Yasur

doi: 10.1007/s11738-009-0449-2pmid: N/A

A laboratory study was undertaken to ascertain the impact and the extent of feeding by different pests on biochemical constituents and various enzyme levels in rice plants. The difference in these parameters due to the pest damage by three different modes of feeding was also studied and compared. The borer pest—yellow stem borer (YSB), Scirpophaga incertulas (W); surface feeder—-leaf roller (LR), Cnaphalocrosis medinalis (G) and a sucking pest—brown plant hopper (BPH), Nilaparvata lugens (S) fed rice plants were analyzed for the quantitative and qualitative changes in biochemical profile and enzymatic changes that occur as plant’s defensive responses were analyzed spectrophotometrically. The phenolic acids were analyzed using HPLC and quantitated with the standard samples. The quantity of biochemicals such as proteins, phenols and carbohydrates has been enhanced along with the enzyme activities of peroxidase (POD), catalase (CAT), chitinase (CHI). A decrease in superoxide dismutase (SOD), phenyl alanine ammonia lyase (PAL), β-1, 3-glucanase (GLU) enzyme activities were evident in pest infested plants. Phenolic acids like vanillic acid, syringic acid, cinnamic acid, and p-coumaric acids were mostly found in the infested plants. We demonstrate that the elevated levels of biochemicals, phenolic acids, and enzymes may play a major role in plant defense.

Agrawal, Anuradha; Sanayaima, Rajkumari; Tandon, Rajesh; Tyagi, Rishi

doi: 10.1007/s11738-009-0450-9pmid: N/A

To decrease the cost of in vitro conservation of banana cv. Karpura Chakkarakeli (AAB; Mysore subgroup) without any adverse effects on cultures, expensive components of medium such as sucrose and gelling agents, i.e. phytagel or agar (90% of the total cost of the medium), were replaced with inexpensive alternates such as market sugar and isabgol, respectively (Experiment 1). In general, no significant effects of isabgol and market sugar were observed on shoot (1.0–1.3 shoots/shoot explant) and root (1.5–2.0 roots/shoot explant) regeneration. Up to 12 months, 100% of cultures survived on isabgol-media, which was significantly higher than that on agar-media (79–83%) and on phytagel-media (51–57%). Isabgol-media with or without other constituents of medium were also tested for survival of banana cultures (Experiment 2); significant differences were observed for survival of cultures (20–100%). Slow growth of the cultures on isabgol-media was attributed to low availability of free water and consequently slower rate of transport of nutrients from isabgol matrix to the plantlets than that of other media tested, as evidenced by significantly lower relative matric potentials (0.801 and 0.804) of isabgol-media. In vitro conservation-derived plants grown in the field exhibited no significant morphological variations. The total cost of medium used for in vitro conservation of banana was decreased by 59% by using isabgol as an alternate gelling agent to agar and phytagel.

Uno, Yuichi; Hashidume, Sae; Kurita, Osamu; Fujiwara, Takayuki; Nomura, Keiichi

doi: 10.1007/s11738-009-0452-7pmid: N/A

α-Mannosidase (EC 3.2.1.24) was purified from ‘Iseimo’, a native variety of Dioscorea opposita Thunb. Before purification, we investigated the composition of a viscous polysaccharide that interferes with column chromatography procedures. The polysaccharide consisted mainly of mannose, and also contained uronic acid. We used the cationic detergent cetylpyridinium chloride (CPC) to remove the polysaccharide. CPC treatment decreased viscosity without affecting α-mannosidase activity. We purified α-mannosidase 2,650-fold. The optimal pH of the enzyme was 6.0 and the optimum temperature was 65°C. The K m value for p-nitrophenyl-α-d-mannopyranoside was 0.35 ± 0.03 mM. Activity was inhibited by swainsonine but not kifunensine. The enzyme cleaved α-1,2 linkages preferentially to α-1,6 and α-1,3 linkages. The M r of purified α-mannosidase was estimated to be 250–260 kDa by gel filtration and native-PAGE. Four polypeptides (86, 83, 80, and 28 kDa) were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It is unclear whether the polypeptides are encoded by one gene or multiple genes. However, N-terminal sequence analysis suggested that post-translational cleavage and/or glycosylation resulted in the three large fragments, if these amino acids were encoded by the same gene. Homology searches and characterization of the enzyme’s properties indicated that Iseimo α-mannosidase belongs to the glycoside hydrolase family 38 proteins, and to the Class II mannosidase group.