Species Of Cruciferae Research Articles

New records in the flora of Siberia and Kazakhstan

New data on the occurrence of 14 vascular plant species of Cruciferae, Liliaceae, Poaceae and Rosaceae in Kazakhstan and Siberia are reported. Fritillaria leucanthta, Potentilla exuta, P. kryloviana and P. × habievii are recorded for the first time from Kazakhstan; Cardamine occulta and Sisymbrium irio – from Siberia. Erysimum amurense is a novelty for the flora of Yakutia; Cardamine hirsuta, Сynodon dactylon and Rorippa austriaca are newly found in Altai Krai; Potentilla agrimonioides is for the first time recorded from the Kalbinskiy Ridge. For Potentilla crantzii, the first reliable finding in Kazakhstan is presented, and the second locality of P. × jakovlevii, a narrow neoendemic of Altai-within-Kazakhstan, is registered. Сynodon is recorded as a new genus for the flora of the Altai Krai while occurrence of Lepidium affine in Kemerovo Province is not confirmed. For each species, a list of recorded localities and brief data on general distribution are provided supplied with morphological comments where needed. Additionally, photos of Fritillaria leucanthta and Potentilla crantzii in their natural habitat are presented along with an image of the herbarium specimen of Potentilla × jakovlevii and morphological comparison of inflorescence and spikelet of Cynodon vs. Digitaria.

New records and deletions of Cruciferae for Russia and some neighbouring countries

Based on the study of collections of LE, RV and RWBG, information on occurrence (or absence) of certain Cruciferae (Brassicaceae) species in Russia and some neighbouring states is updated. Camelina hispida is first recorded from Russia, Camelina sativa from Turkmenistan and Goldbachia torulosa from Ukraine as alien species apparently not naturalized in relevant countries. In contrast, Isatis armena, a novelty for the flora of both Russia and Europe, along with Plagioloba persica for the first time recorded from Kyrgyzstan, appears to be aboriginal elements in the newly revealed localities. At the same time, occurrence of Isatis cardiocarpa in Europe, as well as an introduction ofGoldbachia laevigata in Ukraine does not get support. In addition, the combination Plagioloba perfoliata is validated.

On the occurrence of some species of the mustard family (Cruciferae) in certain regions of Mongolia

On the basis of analysis of relevant literature as well as herbarium collections of LE and MW, unreliability of recent record of four Cruciferae species from easternt Mongolia is proved, viz. Alyssum desertorum (Middle Khalkha), Crucihimalaya mollissima, Sisymbrium brassiciforme (both – East Mongolia), and Meniocus linifolius (Great Khingan). It is found that the species could not be collected in 1987 and false findings are based on the confusion with labels of the season 1984 with similar field numbers, a conclusion further supported by the information from relevant field diaries. It is documented that herbarium collections of joint Soviet-Mongolian biological expedition kept in UBA are mislabeled in a way that at least part of gatherings attributed to 1987 actually represent material collected in 1984 in western Mongolia. This fact should be considered when making floristic and taxonomic research in Mongolia; besides, the need of re-labeling of relevant material in UBA is stressed.

Brassicaceae Burnett in the municipality of Santa Maria, Rio Grande do Sul, Brazil

Brassicaceae (Cruciferae) includes invasive species as well as widely cultivated horticultural species. In Santa Maria, Cruciferae species usually occur in environments that have undergone urbanization such as sidewalks, roadsides, walls, near energy poles, etc. The last listing of species of this family in the area was performed by Romeu Beltrão in 1962 and supplemented in 1965. The objective of the current study was to update the number of records of Brassicaceae species that occur in the municipality of Santa Maria, RS, as well as to provide keys for the identification for native and naturalized genera and species. Bibliographic surveys, field collections, herbarium material analysis and data from databases of speciesLink and Flora of Brazil 2020 were carried out, as well as complementary collections from August 2018 to April 2019. The species found were photographed and identified based on the existing literature. Identification keys for genera and species, as well as illustrations, were prepared. All genera had only one representative species in Santa Maria with the exception of Lepidium, which presented three species. There was an addition of three species and one genus in relation to the last survey carried out.

Transcriptomic analysis of Eruca vesicaria subs. sativa lines with contrasting tolerance to polyethylene glycol-simulated drought stress

BackgroundEruca vesicaria subsp. sativa is one of the Cruciferae species most tolerant to drought stress. In our previous study some extremely drought-tolerant/sensitive Eruca lines were obtained. However little is known about the mechanism for drought tolerance in Eruca.MethodsIn this study two E. vesicaria subs. sativa lines with contrasting drought tolerance were treated with liquid MS/PEG solution. Total RNA was isolated from 7-day old whole seedlings and then applied to Illumina sequencing platform for high-throughput transcriptional sequencing.ResultsKEGG pathway analysis indicated that differentially expressed genes (DEGs) involved in alpha-Linolenic acid metabolism, Tyrosine metabolism, Phenylalanine, Tyrosine and tryptophan biosynthesis, Galactose metabolism, Isoquinoline alkaloid biosynthesis, Tropane, Piperidine and pyridine alkaloid biosynthesis, Mineral absorption, were all up-regulated specifically in drought-tolerant (DT) Eruca line under drought stress, while DEGs involved in ribosome, ribosome biogenesis, Pyrimidine metabolism, RNA degradation, Glyoxylate and dicarboxylate metabolism, Aminoacyl-tRNA biosynthesis, Citrate cycle, Methane metabolism, Carbon fixation in photosynthetic organisms, were all down-regulated. 51 DEGs were found to be most significantly up-regulated (log2 ratio ≥ 8) specifically in the DT line under PEG treatment, including those for ethylene-responsive transcription factors, WRKY and bHLH transcription factors, calmodulin-binding transcription activator, cysteine-rich receptor-like protein kinase, mitogen-activated protein kinase kinase, WD repeat-containing protein, OPDA reductase, allene oxide cyclase, aquaporin, O-acyltransferase WSD1, C-5 sterol desaturase, sugar transporter ERD6-like 12, trehalose-phosphate phosphatase and galactinol synthase 4. Eight of these 51 DEGs wre enriched in 8 COG and 17 KEGG pathways.ConclusionsDEGs that were found to be most significantly up-regulated specifically in the DT line under PEG treatment, up-regulation of DEGs involved in Arginine and proline metabolism, alpha-linolenic acid metabolism and down-regulation of carbon fixation and protein synthesis might be critical for the drought tolerance in Eruca. These results will be valuable for revealing mechanism of drought tolerance in Eruca and also for genetic engineering to improve drought tolerance in crops.

Cutting after grafting affects the growth and cadmium accumulation of Nasturtium officinale.

The growth and cadmium (Cd) accumulation of emergent plant Nasturtium officinale R. Br. cuttings taken from plants grafted onto rootstocks of four terrestrial Cruciferae species were studied in a pot experiment. Scions from N. officinale seedlings were grafted onto rootstocks of Brassica chinensis L., Raphanus sativus L., Brassica napus L., and Rorippa dubia (Pers.) H. Hara. Cuttings were taken after 1month and grown in Cd-contaminated soil (10mg Cd kg-1) for 60days. Compared with non-grafted N. officinale, grafting onto R. sativus and B. napus rootstocks increased the root, shoot, and whole plant biomasses of N. officinale cuttings. Brassica napus rootstock was more effective than R. sativus rootstock for increasing the biomass of N. officinale cuttings. The four rootstocks decreased or had no significant effect on photosynthetic pigment contents in N. officinale cuttings compared with non-grafted N. officinale. Only grafting onto B. napus rootstock enhanced antioxidant enzyme activities. Compared with non-grafted N. officinale, R. sativus and B. napus rootstocks decreased the Cd contents in roots and shoots of N. officinale cuttings, whereas the other rootstocks had no significant effect on the shoot Cd content. The four rootstocks had no increase effects on Cd extraction by N. officinale cuttings. Therefore, cutting after grafting did not enhance the phytoremediation ability of N. officinale for growth in Cd-contaminated soil. However, R. sativus and B. napus rootstocks decreased the Cd content in N. officinale cuttings, which offers a potential approach for N. officinale safety production as a wild vegetable in Cd-contaminated soils.

What is Cochlearia venusta (Cruciferae)?

Available material on the improperly known Cruciferae (Brassicaceae) species, Cochlearia venusta (Pseudosempervivum venustum), is revised and identified. The taxon is found to be conspecific with the eastern Anatolian endemic Noccaea bornmuelleri, previously long known as Thlaspi bornmuelleri (based on Syrenopsis bornmuelleri). The 10-years younger S. bornmuelleri is reduced to synonymy of C. venusta and a combination Noccaea venusta is validated. Original material of both names is briefly discussed; a lectotype (instead of holotype) is recognized for S. bornmuelleri and that is designated for C. venusta.

Spring Ephemerals Adapt to Extremely High Light Conditions via an Unusual Stabilization of Photosystem II.

Ephemerals, widely distributed in the Gobi desert, have developed significant characteristics to sustain high photosynthetic efficiency under high light (HL) conditions. Since the light reaction is the basis for photosynthetic conversion of solar energy to chemical energy, the photosynthetic performances in thylakoid membrane of the spring ephemerals in response to HL were studied. Three plant species, namely two C3 spring ephemeral species of Cruciferae: Arabidopsis pumila (A. pumila) and Sisymbrium altissimum (S. altissimum), and the model plant Arabidopsis thaliana (A. thaliana) were chosen for the study. The ephemeral A. pumila, which is genetically close to A. thaliana and ecologically in the same habitat as S. altissimum, was used to avoid complications arising from the superficial differences resulted from comparing plants from two extremely contrasting ecological groups. The findings manifested that the ephemerals showed significantly enhanced activities of photosystem (PS) II under HL conditions, while the activities of PSII in A. thaliana were markedly decreased under the same conditions. Detailed analyses of the electron transport processes revealed that the increased plastoquinone pool oxidization, together with the enhanced PSI activities, ensured a lowered excitation pressure to PSII of both ephemerals, and thus facilitated the photosynthetic control to avoid photodamage to PSII. The analysis of the reaction centers of the PSs, both in terms of D1 protein turnover kinetics and the long-term adaptation, revealed that the unusually stable PSs structure provided the basis for the ephemerals to carry out high photosynthetic performances. It is proposed that the characteristic photosynthetic performances of ephemerals were resulted from effects of the long-term adaptation to the harsh environments.

Cloning and characterization of the dehydration-responsive element-binding protein 2A gene in Eruca vesicaria subsp sativa.

Eruca vesicaria subsp sativa is one of the most tolerant Cruciferae species to drought, and dehydration-responsive element-binding protein 2A (DREB2A) is involved in responses to salinity, heat, and particularly drought. In this study, a gene encoding EvDREB2A was cloned and characterized in E. vesicaria subsp sativa. The full-length EvDREB2A cDNA sequence contained a 388-bp 5'-untranslated region (UTR), a 348-bp 3'-UTR, and a 1002-bp open reading frame that encoded 334 amino acid residues. The theoretical isoelectric point of the EvDREB2A protein was 4.80 and the molecular weight was 37.64 kDa. The genomic sequence of EvDREB2A contained no introns. Analysis using SMART indicated that EvDREB2A contains a conserved AP2 domain, similar to other plant DREBs. Phylogenetic analysis revealed that EvDREB2A and DREB2As from Brassica rapa, Eutrema salsugineum, Arabidopsis thaliana, Arabidopsis lyrata, and Arachis hypogaea formed a small subgroup, which clustered with DREB2Bs from A. lyrata, A. thaliana, Camelina sativa, and B. rapa to form a larger subgroup. EvDREB2A is most closely related to B. rapa DREB2A, followed by DREB2As from E. salsugineum, A. thaliana, A. hypogaea, and A. lyrata. A quantitative real-time polymerase chain reaction indicated that EvDREB2A expression was highest in the leaves, followed by the roots and hypocotyls, and was lowest in the flower buds. EvDREB2A could be used to improve drought tolerance in crops.

Screening for Eruca genotypes tolerant to polyethylene glycol-simulated drought stress based on the principal component and cluster analyses of seed germination and early seedling growth

Water deficit is an environmental factor that constrains crops to express their ecophysiological potential and causes crop yield reduction. Eruca vesicaria has been reported to be one of the most drought-tolerant species in Cruciferae. In this study, polyethylene glycol-simulated drought tolerance was evaluated in one line of Brassica carinata, one line of Brassica napus and 249 Eruca lines based on the principal component analysis (PCA) and unweighted pair-group arithmetic average (UPGMA) cluster analysis. The PCA based on eight drought tolerance indices indicated that the first three components accounted for 85.46% of the total variation, with principal component (PC) 1 accounting for 43.89%, PC2 for 27.85% and PC3 for 13.73% of the total variation. The UPGMA cluster analysis indicated that B. napus cultivar Zhongshuang 9 and Eruca lines could be clustered into five major groups, with group 1 being, in general, drought sensitive, group 2 being slightly–medium drought tolerant, group 3 being drought tolerant, group 4 being highly drought sensitive and group 5 being highly drought tolerant. B. carinata cultivar XB1, as an outstander, showed high drought sensitivity. The UPGMA cluster dendrogram provides a good representation of the similarity matrix (r= 0.68). The drought-tolerant Eruca materials obtained in this study will be valuable for genetic improvement not only in Eruca itself, but also in Brassica crops since they are drought-tolerant lines from a drought-tolerant species.

Accumulation of heavy metals by North Caucasian plant species of the Cruciferae family in regards to phytoremediation

Heavy metals (Fe, Zn, Mn, Cu, Ni, Co, Pb, and Cd) were analyzed in 61 samples of plant species of the family Cruciferae and 23 samples of North Caucasian soils developed on ultramafic, mafic, and felsic bedrocks. The study revealed the dependence between the chemical composition of plants, geochemical environments, and the taxonomic position of species. We identified two species, Arabis sagittata, an accumulator of Zn, Cu, Ni, and Alyssum murale, a hyperaccumulator of Ni, which can be effective in phytoremediation of heavy-metal contaminated soils.

THE ECOGEOGRAPHIC DISTRIBUTION OF BREEDING SYSTEMS IN THE CRUCIFERAE (BRASSICACEAE) OF ISRAEL

Eighty-six species of Cruciferae in Israel, from two ecologically different types of habitats, desert and Mediterranean, were screened for a possible association between their ecogeographic distribution and their breeding systems. The use of pollen: ovule ratio as a valid indicator for the breeding system was supported by a significant correlation between this ratio and autogamous fruit set in a sample of 28 species. The distribution of breeding systems is largely bimodal. Based on pollen:ovule ratios, 60% of the taxa studied are xenogamous; the remainder are self-compatible and largely autogamous. The percentage of selfers was larger in the desert than in the Mediterranean territory, yet the differences between the frequencies of the two breeding categories in the two ecogeographic territories are not statistically significant. Contrary to the expected, in secondary habitats xenogamous taxa are more frequent than autogamous ones.

제주지역 사찰음식으로 이용되는 식물에 대한 연구

본 연구는 제주지역의 사찰에서 음식으로 이용되는 식물을 파악하기 위하여 2011년 5월부터 2012년 1월까지 수행되었다. 조사대상 사찰은 36개 사찰이었고 설문대상자는 58명이었다. 사찰에서 이용하는 식물종은 27과 51속 55종 2변종 총 57분류군이었다. 이 중, 가장 많이 이용하는 과단위 분류군은 국화과가 8종으로 가장 많고, 십자화과 6종, 산형과 4종 등의 순이었으며, 목본 식물은 10종, 제주지역 자생식물은 25종이었다. 식물체의 이용부위는 잎을 사용하는 종이 19종으로 가장 많았고, 뿌리, 어린순, 열매 순 이었다. 특허검색을 통한 지식재산권을 가지고 있는 식물은 조사식물 대부분이 포함되었고, 이 중 식품관련 특허를 가지고 있는 식물이 48종, 화장품관련 특허를 가지고 있는 것이 34종, 의약관련 특허를 가지고 있는 식물이 38종으로 집계되었다. 제주지역 사찰 음식에 사용하는 식물재료의 구입 및 조달 방법은 주변의 식물 활용보다는 시장 또는 재배에 의존하고, 산나물 채취에 의한 사용은 한정적으로 사용되고 있기 때문에 제주 생물자원의 이용에 대한 전통지식의 수집은 사찰 보다는 다른 조건을 이용한 연구가 필요하다고 사료된다. We examined plants that were used as temple food in Jeju from May 2011 to January 2012. Thirty-six temples participated in the study, and there were 58 questionnaire respondents. Fifty-seven taxa were used as temple food, which belonged to 27 families, 51 genera, 55 species, and two varieties. The most commonly used family-based taxa were eight species of Compositae, six species of Cruciferae, and four species of Umbelliferae. Ten species of woody plants and 25 species of Jeju native plants were also used as temple food. The most useful part was the leaf, followed by the root, leaflet, and fruit. A patent search showed that most of the surveyed plants were covered by intellectual property rights. Forty-eight species had food-related patents, 34 species had cosmetics-related patents, and 38 species had medicine-related patents. The purchase and procurement of Jeju temple food plants usually depended on the market or plant cultivation rather than the use of the plants. Gathering of wild herbs for temple food has been performed on a limited basis. Therefore, collecting traditional knowledge for the use of Jeju plant resources should be conducted under different conditions rather than through a temple-related study.

Interconnected Metabolism of Host Plants and Obligate Biotrophic Pathogens

Downy mildew disease, caused by obligate biotrophic oomycetes in the family Peronsporaceae, affects a wide range of flowering plants, including numerous monocot and dicot crops. Species from the Hyaloperonospora genus are causal agents of downy mildew in Arabidopsis thaliana and many other Cruciferae species, including crops such as broccoli, cabbage, and canola, and the Arabidopsis/ Hyaloperonospora arabidopsidis pathosystem is an established model for downy mildews (Coates and Beynon, 2010). Obligate biotrophic parasites depend on living host cells for their growth and reproduction (reviewed in O’Connell and Panstruga, 2006). This means that, following successful infection, the parasite must establish connections within plant cells (e.g., haustoria) and obtain nourishment from the host without causing immediate host cell death. Therefore, changes in the metabolic state of the host might be expected to influence the growth of obligate biotrophic pathogens and the development of disease. In new work, Stuttmann et al. (pages 2788–2803) describe two distinct mutants of Arabidopsis ,b oth of which show increased resistance to H. arabidopsidis (Hpa) resulting from a disruption in amino acid metabolism causing overaccumulation of the amino acid Thr. Although the mutant plants overaccumulated all three Asp-derived amino acids, Thr, Ile, and Met, enhanced resistance was found to be related specifically to Thr accumulation. Mutant plants that overaccumulate only Met were not hyperresistant to Hpa, and pretreatment of plants with Thr, but not Ile, led to reduced Hpa sporulation (see figure). In addition, the mutations did not cause constitutive plant defense activation, and enhanced resistance did not appear to be linked to plant immunity. Rather, the effect appeared to be due to a loss of susceptibility (i.e., Thr overaccumulation somehow rendered the plant unsuitable for Hpa infection). Interestingly, this effect was specific for Hpa susceptibility, since pretreatment of plants with Thr did not affect sporulation of another obligate biotroph, the powdery mildew ascomycete Golovinomyces orontii (Go). The authors addressed the question of how overaccumulation of Thr might affect Hpa but not Go. Excess Thr is known to be toxic to Arabidopsis, and, indeed, the mutants described in this study were smaller than wild-type plants. An assessment of genes and biochemical pathway components present in the different phyla provided support for the notion that oomycetes and plants might use similar pathways of amino acid biosynthesis and metabolism in a distinct manner from the more distantly related ascomycete. Thus, the toxic effect of high Thr accumulation might be shared among plants and oomycetes, but not by the fungal ascomycete Go. These data provide solid examples of how plant host metabolic state can influence growth and pathogenicity of adapted biotrophic pathogens.

Morphological, ecological and biological variations in the mustard aphid, Lipaphis pseudobrassicae (Kaltenbach) (Hemiptera: Aphididae) from different host plants

Genetic and morphological differentiation of insect populations in relation to the use of different host plants is an important phenomenon that leads to ecological specialization. In this study, we describe variations in morphology, and in ecological and biological parameters of Lipaphis pseudobrassicae (Kaltenbach) clones associated with three host species of Cruciferae, Brassica juncea (L.) var. rai sarson Czern and Cross (brown mustard), Brassica campestris L. var. sarson Prain (yellow mustard), and Rorippa indica (L.) Hiern (wild herb). This study was aimed at obtaining evidence regarding phenotypic differentiation induced by, or associated with, the use of distinct host species. Ten morphological characters, 4 growth parameters and 8 biological functions were investigated in wingless aphids collected from plants of the three host species. Aphids from B. campestris and B. juncea clones were bigger in size, heavier in weight and showed higher growth rates and fecundity than the clones from R. indica. Between the two crop plants, clones from B. juncea showed significantly higher growth rates than the clones from B. campestris. Transfer of L. pseudobrassicae populations from B. campestris to B. juncea and R. indica and vice versa resulted in poor performance. Results indicate that the average phenotype of L. pseudobrassicae individuals inhabiting different host plant species differs as a consequence of the contrasting feeding environments the host species provide.

Differential response of weed and crop species to potassium and sulphur fertilizers

Fertilization may affect the relative competitive ability of weeds and crops if the growth response to fertilizer differs among species. Greenhouse studies were conducted to evaluate the relative biomass yield response of 19 weed species and the crops canola (Brassica napus L.) and spring wheat (Triticum aestivum L.) to potassium (K) and sulphur (S) fertilization. Seven weed species showed a significant increase in biomass production at 6 wk with K fertilization, but biomass production of canola and wheat did not increase with K addition. Sulphur fertilizer increased the biomass production of canola, flixweed (Descurainia sophia L.) and wild mustard (Sinapis arvensis L.), three of the four Cruciferae species evaluated, as well as that of hairy nightshade (Solanum sarrachoides Sendtner), round-leaved mallow (Malva pusilla Sm.) and stork’s-bill [Erodium cirutarium (L.) L’Her. Ex. Ait.]. Sulphur fertilizer did not increase the biomass production of spring wheat or of any grass weed species. The data from the greenhouse study support the concept that fertilization may shift the relative competition between a crop and the weed population if the weeds are more responsive than the crop to the type of fertilizer applied. However, this concept should be tested under field conditions. Key words: Integrated weed management, sulphur, potassium

Floral characters and breeding systems in the dimorphic annual plant Diptychocarpus strictus (Cruciferae)

Diptychocarpus strictus is an early spring ephemeral plant mainly distributed in Junggar Basin of China. It is one of the few species of Cruciferae that has heterocarpy on the same raceme. The upper and lower flowers in a raceme develop into two kinds of siliques that differ in morphology and in manner of dehiscence. This paper deals primarily with the floral syndromes and breeding system of D. strictus. The results can be summarized as follows. (1) This species has two floral morphs, purple-flowered and white-flowered, and the color of flowers is stably inherited. The ratio of the two morphs within a population is close to 1:1. (2) There are significant differences between the two morphs in anther length of the longer stamens in the upper part flowers of a raceme and in length of petal and style of the lower flowers in a raceme (P0.01). Additionally, there are significant differences between the two morphs in length of outer sepals, petals, filaments of longer stamens, ovary, and style between upper and lower flowers in a raceme (P0.01). The data of morphological characters of the upper flowers in a raceme are larger than those of the lower flowers. (3) Number of pollen grains per flower in upper and lower flowers of a raceme in purple-flowered and white-flowered morphs are 7589.07±976.64 and 5428.93±900.45 and 7044.73±557.37 and 5138.60±813.48, respectively; number of ovules per ovary, 31.83±3.36 and 25.03±3.72 and 32.03±3.43 and 25.70±2.61, respectively; and P/O ratios, 241.31±41.85 and 222.33± 52.51 and 222.19±27.80 and 201.84±37.52, respectively. Number of pollen grains per anther is greater in the shorter stamens than they are in the longer stamens of the same flower (P0.01). Abortion rate of pollen is very low, and it differs between longer and shorter stamens (P0.05). (4) In the same raceme of the two morphs, the upper flowers have more pollen grains, higher P/O ratios, and more ovules than the lower flowers (P0.01). Also, there are significant differences between the two morphs in number of pollen grains per anther in the longer stamens of the upper flowers in a raceme (P0.01). (5) Pollen longevity and stigma receptivity barely overlap; the period of highest pollen vigor is just the same as the peak of stigma receptivity. Dynamic curves of pollen viability of the longer and the shorter stamens in the two morphs are similar. At the beginning of anther dehiscence, the pollen vigor of both longer and shorter stamens is 90%. (6) Few pollinators were present during flowering, and self-pollen could germinate normally on the stigma. In the two morphs, fruit-set was 88.2%and 85.7%, respectively, in no emasculation and bagging treatments, and 95.0% and 90.0%, respectively, under conditions of natural pollination, indicating that D. strictus is a facultative selfer.

WEEDS AND WEED MANAGEMENT IN PROCESSING TOMATO

The EWRS (European Weed Research Society) Working Group Weed Management Systems in Vegetables collected information about weeds and Integrated Weed Management programmes in processing tomatoes. Crops are mostly transplanted and the weed communities are commonly very rich of species (both grasses and broad-leaved weeds) but they are made up by a small group of common species (Echinochloa crus-galli, Amaranthus spp., Chenopodium album, Polygonum spp., Portulaca oleracea and Solanum nigrum) throughout the Mediterranean area. In field-seeded crops and in Northern countries, early-emergence weeds (Alopecurus myosuroides, Avena spp., Lolium spp., and several species of Cruciferae and Compositae) are frequent. S. nigrum (plus S. sarrachoides and S. physalifolium in Spain, and S. eleagnifolium in Israel) is the key weed in all the countries. Paper reports species that are becoming an increasing problem in each country. Among parasitic plants, Orobanche spp. is a problem in Spain, Portugal, Morocco, Italy and Israel while Cuscuta campestris in Spain and Israel. A S. nigrum management system should be based on: 1) chemical control in the previous crops where it is easier; 2) preferring transplanted than direct seeded tomatoes; 3) early soil preparation and chemical control of first emergence fluxes of Solanum before tomato planting; 4) row localisation of residual herbicides at planting integrated by inter-row hoeing and/or by split low-dose treatments with metribuzin+rimsulfuron against S. nigrum at very early growth stage (cotyledons). Some news about chemical weed control and about programmes of integrated control of parasitic weeds are also discussed.

Karyological Studies on Some Wild Species of Family Cruciferae in Egypt

Karyological Studies on Some Wild Species of Family Cruciferae in Egypt

The evolutionary origin and genomic organization of SINEs in Arabidopsis thaliana.

We have characterized the two families of SINE retroposons present in Arabidopsis thaliana. The origin, distribution, organization, and evolutionary history of RAthE1 and RAthE2 elements were studied and compared to the well-characterized SINE S1 element from Brassica. Our studies show that RAthE1, RAthE2, and S1 retroposons were generated independently from three different tRNAs. The RAthE1 and RAthE2 families are older than the S1 family and are present in all tested Cruciferae species. The evolutionary history of the RAthE1 family is unusual for SINEs. The 144 RAthE1 elements of the Arabidopsis genome cannot be classified in distinct subfamilies of different evolutionary ages as is the case for S1, RAthE2, and mammalian SINEs. Instead, most RAthE1 elements were probably derived steadily from a single source gene that was maintained intact and active for at least 12-20 Myr, a result suggesting that the RAthE1 source gene was under selection. The distribution of RAthE1 and RAthE2 elements on the Arabidopsis physical map was studied. We observed that, in contrast to other Arabidopsis transposable elements, SINEs are not concentrated in the heterochromatic regions. Instead, SINEs are grouped in the euchromatic chromosome territories several hundred kilobase pairs long. In these territories, SINE elements are closely associated with genes. A retroposition partnership between Arabidopsis SINEs and LINEs is proposed.