Drought stress limits wheat growth and productivity. The response of wheat (Triticum aestivum L.) to different water supply conditions (well-watered and drought-stressed) and exogenous methyl jasmonate (MeJA; 0 and 0.25 μM) was studied. The application of MeJA enhanced wheat adaptability to drought stress by physiological and metabolic adjustments. Drought stress reduced net photosynthetic rate (PN), stomatal conductance (gs), transpiration rate (E), and water-use efficiency (WUE) in wheat. The application of exogenous MeJA decreased also gs and E, but stimulated WUE. Meanwhile, MeJA mitigated the decline of PN, gs, and WUE induced by drought stress and midday depression by 6-183%. Both drought stress and exogenous MeJA induced stomatal closure, which improved water status and delayed plant senescence. MeJA enhanced the activities of superoxide dismutase, peroxidase, catalase, and reduced malondialdehyde content. PN-PAR response curves showed that MeJA mitigated the decline of maximum PN, apparent quantum yield, and saturation irradiance, and the increase of compensation irradiance. Drought stress and exogenous MeJA increased dark respiration rate and showed an additive effect. These results indicated that 0.25 μM MeJA enhanced the photosynthesis under drought stress mainly by improving the water status and antioxidant capacity of wheat., C. Ma, Z. Q. Wang, L. T. Zhang, M. M. Sun, T. B. Lin., and Obsahuje bibliografii
Six genotypes of taro (Colocasia esculenta L. Schott) were evaluated under in vitro and in vivo polyethylene glycol (PEG-6000)-mediated osmotic stress conditions. A significant variation in growth response was observed among the taro genotypes under in vitro-induced stress conditions. In vivo results indicated a significant effect of osmotic stress on photosynthetic parameters, such as net photosynthetic rate, transpiration rate, stomatal conductance, stomatal resistance, internal CO2 concentration, carboxylation efficiency, and transpiration efficiency on the tested genotypes at the tuberization stage. Lesser variations in photosynthesis and higher accumulation of proline, phenols, and antioxidative enzymes, namely, superoxide dismutase and guaiacol peroxidase, were associated with yield maintenance under osmotic stress conditions. The genotypes DP-89, IGCOL-4, and Ramhipur showed a higher degree of tolerance towards osmotic stress with a minimum variation in the studied parameters. These genotypes could be lines of interest for intensification of breeding strategies to develop drought-tolerant plants., M. R. Sahoo, M. Dasgupta, P. C. Kole, A. Mukherjee., and Obsahuje bibliografii
The extensive genus Erebia is divided into several groups of species according to phylogenetic relatedness. The species Erebia medusa was assigned to the medusa group and E. epipsodea to the alberganus group. A detailed study of the morphology of their copulatory organs indicated that these species are closely related and based on this E. epipsodea was transferred to the medusa group. Phylogenetic analyses of the gene sequences of mitochondrial cytochrome C oxidase subunit I (COI) and mitochondrial NADH dehydrogenase subunit 1 (ND1) confirm that E. medusa and E. epipsodea are closely related. A possible scenario is that the North American species, E. episodea, evolved after exclusion/isolation from E. medusa, whose current centre of distribution is in Europe., Martina Šemeláková, Peter Pristaš, Lubomír Panigaj., and Obsahuje seznam literatury
This study reports the results of a molecular phylogenetic analysis of thirty three species of Ennominae (Lepidoptera: Geometridae). The aim of this analysis was to determine the phylogenetic affinities of 13 European species not previously studied using these methods. Fragments of seven nuclear genes, elongation factor 1 alpha (EF-1α), wingless (wgl), isocitrate dehydrogenase (IDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ribosomal protein S5 (RpS5) and expansion segments D1 and D2 of the 28S rRNA gene and fragment of one mitochondrial gene, cytochrome oxidase subunit I (COI), were used. In the analysis using Bayesian phylogenetic inference, original gene sequences of the target species were combined with a larger data matrix of 20 species of Ennominae, used in a previous study (Wahlberg et al., 2010, Mol. Phylogenet. Evol. 55: 929-938). Most notably, the results indicate that the representatives of the genera Cepphis, Plagodis, Pseudopanthera and Selenia form a well-supported monophyletic group which appeared as the sister clade to the rest of the "ennomine" group of tribes. On the other hand, Crocallis and Opisthograptis group together with Ennomos. These results conflict with previous tribal subdivisions of the subfamily pointing to the need to reconsider the concepts of Ennomini and Ourapterygini. Within the tribe Macariini, the genus Macaria appears to be more closely related to Itame (= Speranza) than to Chiasmia clathrata. The emerging phylogenetic tree of Ennominae suggests only a limited phylogenetic inertia in body size making this group a promising target for comparative studies on this central life history trait and its correlates. and Erki Õunap, Juhan Javoiš, Jaan Viidalepp, Toomas Tammaru.
A new genus and new species of Cantacaderinae (Heteroptera: Tingidae) is described, Caledoderus monteithi. A key to genera is provided. The phylogenetic relationships among the Cantacaderinae, including this new genus and species, are revisited. The results are congruent with previous studies. However, the Ceratocaderini is a sister group of Carldrakeaninae and not Cantacaderini, even if only weakly supported by the analysis. Therefore, the status of Ceratocaderini and Cantacaderini is maintained, whereas Carldrakeanini stat. nov. is reduced to tribal level and they are all included in the Cantacaderinae., Eric Guilbert., and Obsahuje seznam literatury
1_External morphological characters were used to reconstruct a phylogeny of the mite family Syringophilidae (Acariformes: Cheyletoidea), which are permanent parasites inhabiting the quills of bird feathers. A total of 53 syringophilid genera and 79 characters were included in the data matrix; maximum parsimony (MP) and Bayesian analyses (BA) were performed to determine their phylogenetic relationships. The consensus of unweighted MP trees was weakly resolved. Only four generic groups were recognized: Aulonastus + Krantziaulonastus (i) and (Creagonycha + Kethleyana) + (Megasyringophilus + Selenonycha) (ii) – both with low Bremer support (BS 1); the subfamily Picobiinae – Picobia, Calamincola, Columbiphilus (Neopicobia + Rafapicobia) (BS 12) (iii) and Psittaciphilus generic group – (Meitingsunes + Psittaciphilus) (Peristerophila + (Neoperisterophila + (Castosyringophilus + Terratosyringophilus))) (BS 2) (iv). BA revealed a consensus tree with a topology similar to MP. The two main groups recognized by MP, the subfamily Picobiinae and Psittaciphilus, both received the highest support of 1; while two other groups recognized by MP – Aulonastus + Krantziaulonastus and (Creagonycha + Kethleyana) + (Megasyringophilus + Selenonycha) received relatively low support of 0.73–74 and 0.76–77, respectively., 2_The consensus of re-weighted MP trees was almost fully resolved but, the majority of the generic groups, excluding the Picobiinae and Psittaciphilus were supported by just a few non-unique synapomorphies with a high probability of homoplastic origin. The most intriguing result is the paraphyly of the Syringophilinae in respect to picobiines. The pattern of the re-weighted tree demonstrates only patches of parallel evolution at the level of syringophilid genera and bird orders. Perhaps horizontal shifts on phylogenetically distant hosts and colonization of quill (calamus) types other than primaries and secondaries were also important in the evolution of the syringophilids., Maciej Skoracki, Eliza Glowska, Andre V. Bochkov., and Obsahuje seznam literatury
Caffeine, a purine alkaloid, is reported to act both as an inducer or inhibitor to plant growth in various species. The aim of this study was to examine the effect of exogenous caffeine on tobacco (Nicotiana tabacum) plants, a plant that does not naturally synthesise caffeine. A hydroponic experiment was carried out in a growth chamber for 14 d using Hoagland’s solution supplemented with 0 (control), 25, 50, 100, 1,000; and 5,000 μM caffeine. None of the investigated caffeine concentrations significantly decreased the net photosynthetic rate except the highest concentrations of 1,000 and 5,000 μM. Light microscopy of thick-sectioned roots showed that 1,000 μM and 5,000 μM caffeine-treated plants possessed deformed epidermal cells, reduced number of cortical cells, and deformed vascular tissues with cells exhibiting thickened xylem walls as compared with control plants. Moreover, transmission electron micrographs of roots revealed that mitochondria and the plasma membrane were affected., R. Alkhatib, B. Alkhatib, L. Al-Eitan, N. Abdo, M. Tadros, E. Bsoul., and Obsahuje bibliografii
The present study revealed that Ginkgo biloba and Platanus occidentalis, the most abundant roadside trees in Seoul, grown under polluted environmental conditions, displayed lower contents of total chlorophyll (Chl), carotenoids (Car), and ascorbic acid (AsA) compared to the trees grown under clean conditions. The reduction in Chl, Car, and AsA contents was 59, 53, and 50%, respectively, in G. biloba, contrary to 26, 23, and 24%, respectively, in P. occidentalis. Furthermore, relative ion leakage and leaf temperature was higher in the trees grown under polluted conditions than in those grown under clean conditions. The increase in relative ion leakage and leaf temperature was 58 and 3% for G. biloba and 17 and 4% for P. occidentalis, respectively. Our results, therefore, highlighted the negative impact of urban environmental pollution on the physiological and biochemical parameters in roadside trees., H. N. You, S. Y. Woo, C. R. Park., and Seznam literatury
Flooding is common in lowlands and areas with high rainfall or excessive irrigation. A major effect of flooding is the deprivation of O2 in the root zone, which affects several biochemical and morphophysiological plant processes. The objective of this study was to elucidate biochemical and physiological characteristics associated with tolerance to O2 deficiency in two clonal cacao genotypes. The experiment was conducted in a greenhouse with two contrasting clones differing in flood tolerance: TSA-792 (tolerant) and TSH-774 (susceptible). Leaf gas exchange, chlorophyll (Chl) fluorescence, chemical composition and oxidative stress were assessed during 40 d for control and flooded plants. Flooding induced a decrease in net photosynthesis, stomatal conductance and transpiration of both genotypes. In flood conditions, the flood-susceptible clone showed changes in chlorophyll fluorescence, reductions in chlorophyll content and increased activity of peroxidase and polyphenol oxidase. Flooding also caused changes in macro- and micronutrients, total soluble sugars and starch concentrations in different plant organs of both genotypes. Response curves for the relationship between photosynthetically active radiation (PAR) and net photosynthetic rate (PN) for flooded plants were similar for both genotypes. In flood conditions, the flood-susceptible clone exhibited (1) nonstomatal limitations to photosynthesis since decreased in maximum potential quantum yield of PSII (Fv/Fm) values indicated possible damage to the PSII light-harvesting complex; (2) oxidative stress; (3) increased leaf chlorosis; and (4) a reduction in root carbohydrate levels. These stresses resulted in death of several plants after 30 d of flooding., F. Z. Bertolde ... [et al.]., and Obsahuje bibliografii
We examined the physiological and biochemical responses of two halophytic grasses with different photosynthetic pathways, Puccinellia tenuiflora (C3) and Chloris virgata (C4), to saline-alkaline stresses. Plants were grown at different Na2CO3 concentrations (from 0 to 200 mM). Low Na2CO3 (< 12.5 mM) enhanced seed germination and plant growth, whereas high Na2CO3 concentrations (> 100 mM) reduced seed germination by 45% in P. tenuiflora and by 30% in C. virgata. Compared to C. virgata, P. tenuiflora showed lower net photosynthesis, stomatal conductance, intercellular CO2 concentration, and water-use efficiency under the same treatment. C. virgata exhibited also relatively higher ATP content, K+ concentration, and the K+/Na+ ratio under the stress treatments implying that salt tolerance may be the main mechanism for salt resistance in this species. Our results demonstrated that the C. virgata was relatively more resistant to saline-alkaline stress than the co-occurring P. tenuiflora; both two species adapt to their native saline-alkaline habitat by different physiological mechanisms., C. Y. Guo, X. Z. Wang, L. Chen, L. N. Ma, R. Z. Wang., and Obsahuje bibliografii