Rosette Stage Research Articles

PM 9/20 (1) Parthenium hysterophorus

PM 9/20 (1) <i>Parthenium hysterophorus</i>

Glyphosate-Resistant Horseweed (Conyza canadensis) Control with Dicamba in Alabama

The development and spread of glyphosate-resistant (GR) horseweed has increased the use of dicamba as an alternative herbicide treatment. Research evaluated suspected glyphosate-resistant horseweed populations from DeKalb (GR-1) and Cherokee (GR-2) counties, Alabama, for response to glyphosate, dicamba, and glyphosate + dicamba. Populations used for resistance determination were tested at rosette and bolt growth stages. Glyphosate resistance evaluation treatments ranged from 0 to 36.0 kg ae ha−1. Data confirmed that GR-1 and GR-2 horseweed populations were 3.0 to 38 times more resistant to glyphosate than the susceptible population, according to population, data type, and growth stage at treatment. GR-1 and GR-2 populations were further evaluated for response to dicamba. Dicamba was applied at 0 to 1.12 kg ai ha−1, both with and without the addition of glyphosate at 1.12 kg ae ha−1. All populations had similar tolerance to dicamba, with the exception of GR-2 treated at the rosette growth stage, which had ~2-fold greater tolerance. When glyphosate was tank-mixed with dicamba, the response of GR populations was similar to that of dicamba alone. Therefore, any potential resistance-management benefit of tank-mixing dicamba with glyphosate may be negated when one is attempting to control GR horseweed. Conversely, adding glyphosate to dicamba drastically enhanced control of the susceptible population at both growth stages.

Nutritional status of winter oilseed rape in cardinal stages of growth as the yield indicator

Nutritional status of the seed crop during its vegetative growth is a tool for a reliable yield prognosis. This approach has been validated for oilseed rape in three 2007/2008, 2008/2009, and 2009/2010 seasons. The field experimental design was: untreated control, NP, NPK, NPKMgS1 (1/3 total MgS rate, spring applied), NPKMgS2 (total rate, autumn), NPKMgS3 (2/3 - autumn, 1/3 - spring). The concentrations of N, P, K, Ca, Mg, Mn, Zn, and Cu were measured in two stages: rosette (whole plant) and flowering (leaves). The yield prognosis was based on path analysis and stepwise regression. The elevated concentration of P, Ca, and Zn in plants at the rosette stage was the early symptom of nutrient imbalance. The Mg concentration in plant leaves at flowering was revealed as the decisive yield predictor. The manner of its management in plant canopy during the yield forming period (YFP) was crucial for the harvested yield. It was documented that each factor leading to increase in Ca but decrease in Mg concentration resulted in yield decrease. The key reason of Mg shortage was its low uptake during the YFP and simultaneous increase in Mn concentration.

AtTCTP2, an Arabidopsis thaliana homolog of Translationally Controlled Tumor Protein, enhances in vitro plant regeneration.

The Translationally Controlled Tumor Protein (TCTP) is a central regulator of cell proliferation and differentiation in animals, and probably also in plants. Arabidopsis harbors two TCTP genes, AtTCTP1 (At3g16640), which is an important mitotic regulator, and AtTCTP2 (At3g05540), which is considered a pseudogene. Nevertheless, we have obtained evidence suggesting that this gene is functional. Indeed, a T-DNA insertion mutant, SALK_045146, displays a lethal phenotype during early rosette stage. Also, both the AtTCTP2 promoter and structural gene are functional, and heterozygous plants show delayed development. AtTCTP1 cannot compensate for the loss of AtTCTP2, since the accumulation levels of the AtTCTP1 transcript are even higher in heterozygous plants than in wild-type plants. Leaf explants transformed with Agrobacterium rhizogenes harboring AtTCTP2, but not AtTCTP1, led to whole plant regeneration with a high frequency. Insertion of a sequence present in AtTCTP1 but absent in AtTCTP2 demonstrates that it suppresses the capacity for plant regeneration; also, this phenomenon is enhanced by the presence of TCTP (AtTCTP1 or 2) in the nuclei of root cells. This confirms that AtTCTP2 is not a pseudogene and suggests the involvement of certain TCTP isoforms in vegetative reproduction in some plant species.

Growth, yield, and yield components of canola as affected by nitrogen, sulfur, and boron application

AbstractDeveloping efficient nutrient management regimes is a prerequisite for promoting canola (Brassica napus L.) as a viable cash crop in eastern Canada. Field experiments were conducted to investigate the growth, yield, and yield components of canola in response to various combinations of preplant and sidedress nitrogen (N) with soil‐applied sulfur (S) and soil and foliar‐applied boron (B). Canola yield and all its yield components were strongly correlated (r2 = 0.99) with the amount of N applied, as was the above‐ground biomass at 20% flowering and the leaf area index. Sidedress N was more efficiently utilized by the crop, leading to greater yields than preplant N application. On average, canola yields increased by 9.7 kg ha−1 for preplant N application and by 13.7 kg ha−1 for sidedress N application, for every kg N ha−1 applied, in 6 of the 10 site‐years. Soil‐applied S also increased canola yields by 3–31% in 7 of the 10 site‐years, but had no effect on yield components. While there was no change in yield from soil‐applied B, the foliar B application at early flowering increased yields up to 10%, indicating that canola plants absorb B efficiently through their leaves. In summary, canola yields were improved by fertilization with N (8 of 10 site‐years), S (7 of 10 site‐years) and B (4 of 10 site‐years). Yield gains were also noted with split N‐fertilizer application that involved sidedressing N between the rosette and early flowering stage. Following these fertilizer practices could improve the yield and quality of canola crop grown in rainfed humid regions similar to those in eastern Canada.

A profiling approach of the natural variability of foliar N remobilization at the rosette stage gives clues to understand the limiting processes involved in the low N use efficiency of winter oilseed rape.

Oilseed rape, a crop requiring a high level of nitogen (N) fertilizers, is characterized by low N use efficiency. To identify the limiting factors involved in the N use efficiency of winter oilseed rape, the response to low N supply was investigated at the vegetative stage in 10 genotypes by using long-term pulse-chase (15)N labelling and studying the physiological processes of leaf N remobilization. Analysis of growth and components of N use efficiency allowed four profiles to be defined. Group 1 was characterized by an efficient N remobilization under low and high N conditions but by a decrease of leaf growth under N limitation. Group 2 showed a decrease in leaf growth under low N supply that was associated with a low N remobilization efficiency under both N supplies despite a high remobilization of soluble proteins. In response to N limitation, Group 3 is characterized by an increase in N use efficiency and leaf N remobilization compared with high N that is not sufficient to sustain the leaf biomass production at a similar level to non-limited plants. Genotypes of Group 4 subjected to low nitrate were able to maintain leaf growth to the same level as under high N. The profiling approach indicated that enhancement of amino acid export and soluble protein degradation was crucial for N remobilization improvement. At the whole-plant level, N fluxes revealed that Group 4 showed a high N remobilization in source leaves combined with a better N utilization in young leaves. Consequently, an enhanced N remobilization limits N loss in fallen leaves, but this remobilized N needs to be efficiently utilized in young leaves to improve N use efficiency.

Differential Susceptibility of &amp;lt;i&amp;gt;Conyza bonariensis&amp;lt;/i&amp;gt; Biotypes to Glyphosate and ALS-Inhibiting Herbicides in Argentina

The aim of this study was to compare control of three stages biotypes (rosette, bolting, and repro- ductive stage) of Conyza bonariensis glyphosate susceptible biotype (S) and tolerant biotype (T) to glyphosate with glyphosate and mixtures of acetolactate synthase (ALS)-inhibiting. For glyphosate, the dose-response curves confirmed that injury of the biotype T relative to biotype S was signifi- cantly lower for both rosette and bolting stages. Resistance index (RI) for this herbicide was approximately 4 for both weed stages. At bolting, for both biotypes doses much higher than the recommended dose were required. For acetolactate synthase (ALS)-inhibiting herbicides, at the rosette stage, control of both biotypes was excellent with doses significantly lower than the recommended rate. All herbicides within this group showed a very low I50 relative to the recommended rate. These results indicate that biotypes difficult to control with glyphosate at the rosette and bolting stage may be controlled using acetolacte synthase (ALS)-inhibiting herbicides. Control for the reproductive stage was poor. A management program based on the combination of glyphosate with pre- and post-emergence acetolactate synthase (ALS) herbicides may be effective to control the weed.

Engraftable neural crest stem cells derived from cynomolgus monkey embryonic stem cells

Neural crest stem cells (NCSCs), a population of multipotent cells that migrate extensively and give rise to diverse derivatives, including peripheral and enteric neurons and glia, craniofacial cartilage and bone, melanocytes and smooth muscle, have great potential for regenerative medicine. Non-human primates provide optimal models for the development of stem cell therapies. Here, we describe the first derivation of NCSCs from cynomolgus monkey embryonic stem cells (CmESCs) at the neural rosette stage. CmESC-derived neurospheres replated on polyornithine/laminin-coated dishes migrated onto the substrate and showed characteristic expression of NCSC markers, including Sox10, AP2α, Slug, Nestin, p75, and HNK1. CmNCSCs were capable of propagating in an undifferentiated state in vitro as adherent or suspension cultures, and could be subsequently induced to differentiate towards peripheral nervous system lineages (peripheral sympathetic neurons, sensory neurons, and Schwann cells) and mesenchymal lineages (osteoblasts, adipocytes, chondrocytes, and smooth muscle cells). CmNCSCs transplanted into developing chick embryos or fetal brains of cynomolgus macaques survived, migrated, and differentiated into progeny consistent with a neural crest identity. Our studies demonstrate that CmNCSCs offer a new tool for investigating neural crest development and neural crest-associated human disease and suggest that this non-human primate model may facilitate tissue engineering and regenerative medicine efforts.

Field application of mycorrhizal bio-inoculants affects the mineral uptake of a forage legume (Hedysarum coronarium L.) on a highly calcareous soil.

The efficiency of two mycorrhizal bio-inoculants on the mineral uptake during the growth stages of a Mediterranean forage legume sulla (Hedysarum coronarium L.) was studied in the field on a highly calcareous soil. The first inoculum (Mm) was made up of a mixture of native arbuscular mycorrhizal fungi (AMF) isolated from calcareous soils: Septoglomus constrictum, Funneliformis geosporum, Glomus fuegianum, Rhizophagus irregularis and Glomus sp. The second was a commercial inoculum (Mi) containing one AMF species: R. irregularis. Both mycorrhizal inoculants increased total and arbuscular colonization of sulla roots. Inoculation with Mm showed a positive effect on sulla shoot dry weight (SDW) when compared to Mi and non-inoculated plants (control). Mineral contents (P, Mg, Mn, Fe) were higher in the shoots of sulla plants cultivated on mycorrhiza-inoculated plots compared to non-inoculated ones. This enhancement was observed during the flowering stage for P, Mg and Mn and during the rosette stage for Fe. An increase in P content of 50 % in plants inoculated with Mm compared to non-inoculated ones may be explained by the induction of root alkaline and acid phosphatase activities. Higher efficiency of native AMF species adapted to calcareous soils opens the way towards the development of mycorrhiza bio-fertilizers targeted to improve sustainable fertilization management in such soils.

Diagnosis of sugar beet (Beta vulgaris L.) nutrient imbalance by DRIS and CND-clr methods at two stages during early growth

ABSTRACTHigh yield of sugar beet require adequate mineral nutrition. To be diagnosed across interacting nutrients using appropriate interpretation models, the plant must be sampled at a critical physiological stage. This study aimed to develop and validate norms at the 7-leaf and well-developed rosette stages, for diagnostic purposes using the Diagnosis and Recommended Integrated System (DRIS) and Compositional Nutrient Diagnosis based on centered log ratios (CND-clr). Data on nutrient concentrations and plant performance were obtained from 409 plots in West-Central Poland. With respect to the growth stages, for physiological and practical reasons, the 7-leaf stage is preferable for diagnostic purposes. At this growth stage, the high-yield subpopulation characterized by higher concentration of potassium and sodium compared to other nutrients. CND-clr indices were closely related to DRIS indices (R2 > 0.93). The CND-clr indices, however, better explained the differences in the white sugar yield within the validated dataset than the DRIS indices.

Meadow Knapweed (Centaurea debeauxii) Response to Herbicides and Mechanical Control

AbstractMeadow knapweed is a fertile European hybrid between black and brown knapweed that has expanded its North American distribution to 27 of the United States and four provinces in Canada. Two experiments were conducted on meadow knapweed in northwestern Washington to determine (1) whether meadow knapweed is similarly sensitive to several herbicides commonly used to control related knapweeds, (2) if herbicide application timing plays a role in control of meadow knapweed, and (3) whether mowing before, after, or instead of herbicide treatment can aid in meadow knapweed control. In the first experiment, herbicides were applied to meadow knapweed at rosette or bolting stages of growth, and again with the same herbicides in the autumn. In the summer following treatment, clopyralid alone or with 2,4-D, dicamba + 2,4-D, and triclopyr ester + 2,4-D ester provided 81 to 100% meadow knapweed control; the only other treatment providing similar control was glyphosate + ammonium sulfate applied at bolting and in autumn in the 2004 to 2005 trial. In the second experiment, combinations of mowing and dicamba + 2,4-D were applied at rosette or early flowering stages of growth. In the 2002 to 2003 trial, control when dicamba + 2,4-D was used exceeded 90%, except when meadow knapweed was mowed at rosette and sprayed at early flowering (78% control). Mowing twice the previous year had only a slight effect on meadow knapweed (10% control). Grass biomass exceeded meadow knapweed biomass in all herbicide-treated plots. In the 2004 to 2005 trial, meadow knapweed control and grass biomass was maximized when plots were mowed at rosette and treated with dicamba + 2,4-D at early flowering or when treated twice with these herbicides; these were the only treatments where grass biomass exceeded meadow knapweed biomass.

Multi-gene silencing in Arabidopsis: a collection of artificial microRNAs targeting groups of paralogs encoding transcription factors.

Functional redundancy often hampers the analysis of gene families. To overcome this difficulty, we constructed Arabidopsis thaliana lines that expressed artificial microRNAs designed to simultaneously target two to six paralogous genes encoding members of transcription factor families. Of the 576 genes that we chose as targets, only 122 had already been functionally studied at some level. As a simple indicator of the inhibitory effects of our amiRNAs on their targets, we examined the amiRNA-expressing transgenic lines for morphological phenotypes at the rosette stage. Of 338 transgenes tested, 21 caused a visible morphological phenotype in leaves, a proportion that is much higher than that expected as a result of insertional mutagenesis. Also, our collection probably represents many other mutant phenotypes, not just those in leaves. This robust, versatile method enables functional examination of redundant transcription factor paralogs, and is particularly useful for genes that occur in tandem.

Production of guaianolides in Agrobacterium rhizogenes - transformed chicory regenerants flowering in vitro

Chicory (Cichorium intybus L.) is rich in bitter sesquiterpene lactones, mainly guaianolides: lactucin, 8-deoxylactucin, lactupicrin and their 11(S),13-dihydroderivatives—compounds recognized for their antimicrobial and anti-cancer effects. In vitro plant tissue culture, and particularly Agrobacterium rhizogenes—generated hairy root (HR) cultures, have many advantages as systems for production of valuable secondary metabolites. Although chicory HRs grow better than control culture, having nearly 60 times greater fresh weight gain, they do not contain a higher content of guaianolides than wild type (wt) roots. Thus we have established in vitro system comprised of wt root and HR cultures, and wt and transformed regenerated plants of the same age, in rosette and flowering stage, in order to study the effects of transformation, organogenesis and flowering on guaianolides production. Both regeneration and flowering in vitro were spontaneous, so the results were not influenced by exogenous growth regulators. Some of the transformed clones grew better, but all flowered earlier in comparison to wt plants. Floral transition increased guaianolides content in both roots and leaves of transformed, but not of wt plants. Expression of RolC oncogene correlated with floral transition and with guaianolides accumulation. We propose A. rhizogenes—transformed plants at the flowering stage as an alternative source of free guaianolides, where, in contrast to HRs, entire plants can be used for the extraction.

Growth, Photosynthesis and Chlorophyll Fluorescence of Chinese Cabbage in Response to High Temperature

In order to gain insight into the physiological responses of plants to high temperature stress, the effects of temperature on Chinese cabbage (Brassica campestris subsp. napus var. pekinensis cv. Detong) were investigated through analyses of photosynthesis and chlorophyll fluorescence under 3 different temperatures in the temperature gradient tunnel. Growth (leaf length and number of leaves) during the rosette stage was greater at ambient + 4℃ and ambient + 7℃ temperatures than at ambient temperature. Photosynthetic CO₂ fixation rates of Chinese cabbage grown under the different temperatures did not differ significantly. However, dark respiration rate was significantly higher in the cabbage that developed under ambient temperature relative to elevated temperature. Furthermore, elevated growth temperature increased transpiration rate and stomatal conductance resulting in an overall decrease of water use efficiency. The chlorophyll a fluorescence transient was also considerably affected by high temperature stress; the fluorescence yield F J , F I , and F P decreased considerably at ambient + 4℃ and ambient + 7℃ temperatures, with induction of F K and decrease of F V /F O . The values of RC/CS, ABS/CS, TRo/CS, and ETo/CS decreased considerably, while DIo/CS increased with increased growth temperature. The symptoms of soft-rot disease were observed in the inner part of the cabbage heads after 7, 9, and/or 10 weeks of cultivation at ambient + 4℃ and ambient + 7℃ temperatures, but not in the cabbage heads growing at ambient temperature. These results show that Chinese cabbage could be negatively affected by high temperature under a future climate change scenario. Therefore, to maintain the high productivity and quality of Chinese cabbage, it may be necessary to develop new high temperature tolerant cultivars or to markedly improve cropping systems. In addition, it would be possible to use the non-invasive fluorescence parameters F O , F V /F M , and F V /F O , as well as FK, MO, SM, RC/CS, ETo/CS, PI abs , and SFI abs (which were selected in this study), to quantitatively determine the physiological status of plants in response to high temperature stresses.

Effects of Native Herbs and Light on Garlic Mustard (Alliaria petiolata) Invasion

AbstractThe degree to which invasive species drive or respond to environmental change has important implications for conservation and invasion management. Often characterized as a driver of change in North American woodlands, the invasive herb garlic mustard may instead respond to declines in native plant cover and diversity. We tested effects of native herb cover, richness, and light availability on garlic mustard invasion in a Minnesota oak woodland. We planted 50 garlic mustard seeds into plots previously planted with 0 to 10 native herb species. We measured garlic mustard seedling establishment, survival to rosette and adult stages, and average (per plant) and total (per plot) biomass and silique production. With the use of structural equation models, we analyzed direct, indirect, and net effects of native cover, richness, and light on successive garlic mustard life stages. Native plant cover had a significant negative effect on all life stages. Species richness had a significant positive effect on native cover, resulting in indirect negative effects on all garlic mustard stages, and net negative effects on adult numbers, total biomass, and silique production. Light had a strong negative effect on garlic mustard seedling establishment and a positive effect on native herb cover, resulting in significant negative net effects on garlic mustard rosette and adult numbers. However, light's net effect on total garlic mustard biomass and silique production was positive; reproductive output was high even in low-light/high-cover conditions. Combined effects of cover, richness, and light suggest that native herbs provide biotic resistance to invasion by responding to increased light availability and suppressing garlic mustard responses, although this resistance may be overwhelmed by high propagule pressure. Garlic mustard invasion may occur, in part, in response to native plant decline. Restoring native herbs and controlling garlic mustard seed production may effectively reduce garlic mustard spread and restore woodland diversity.

Photosynthetic capacity of the inflorescence is a major contributor to daily-C-gain and the responsiveness of growth to elevated CO2 in Arabidopsis thaliana with repressed expression of mitochondrial-pyruvate-dehydrogenase-kinase

The balance between whole-plant net-photosynthesis (Pn) and dark-respiration (Rd) determines daily-C-gain (dC) and thus growth. However, in Arabidopsis thaliana, a well-studied organism, the contribution of the inflorescence as a respiring sink and a photosynthetic source has never been quantified together in either ambient CO2 (AC) or elevated CO2 (EC) conditions. When sink-strength is altered by modifying mitochondrial pyruvate metabolism increases in productivity can occur in both AC and EC. Rd and Pn during canopy transition from its rosette-leaf form to the highly branched inflorescence stages were quantified. Diel patterns of leaf and whole-plant gas exchange were measured at four critical developmental stages for controls (wild-type (WT) and plasmid (pBI121)) and two transgenics (3′1 and 10′4) Arabidopsis lines having partial constitutive repression of mitochondrial pyruvate dehydrogenase kinase (mtPDHK) grown at AC and EC.In all lines the mature inflorescence structures, although having higher Rd than the rosette leaves, contributed over 90% of Pn and dC at both AC and EC. Expressed on a plant basis, Pn, Rd and dC were 700–900% higher and water-use-efficiency (WUE) was double when the inflorescence was mature as when the rosette-leaves alone sustained growth. On a dry-matter basis Pn, Rd and dC were 50–75% lower, but on a surface-area basis these traits were remarkably constant during development, reflecting the high photosynthetic strength and carbon-use-efficiency (CUE) of the inflorescence. All lines demonstrated greater Pn, Rd, dC and WUE under EC, however, at the rosette stage the controls responded more to EC, whereas, during the inflorescence 3rd-stage it was the transgenics that responded more to EC.These results underscore the need for measuring key phenotype traits such as whole-plant Pn, Rd and dC to assess how source and sink strengths change during the life-cycle, especially following genetic modification of a primary metabolic process.

Dissipation and persistence of major herbicides applied in transgenic and non-transgenic canola production in Quebec

After soybeans, canola is the second most important oilseed crop in Canada, with more than 99% of the canola cultivation consisting of herbicide resistant (HR) varieties. The expansion in HR canola cultivation has led to the increasing use of the same herbicides for weed control which has resulted in a growing concern about their impact on the environment. The present study was conducted to investigate the dissipation and transport of the herbicides, glyphosate and glufosinate, in soil used for the transgenic production of canola and a comparison was made with the herbicide, trifluralin, used in non-transgenic canola. Commercially grown HR transgenic canola varieties and a conventional canola variety were planted in a randomized complete block design. The plots planted with Roundup Ready and Liberty Link cultivars were treated with glyphosate and glufosinate, respectively, at the 2–3 leaf stage and at the rosette stage in each replication. On conventional canola plots, trifluralin was incorporated into soil a day before planting. Soil samples were collected from two depths, 0–0.15 m and 0.15–0.30 m, at different time intervals (1, 7 and 20 days) after the application of the herbicide. Analysis of the soil samples was done by HPLC (high performance liquid chromatography) to determine the residual amounts of herbicide in the soil. Glufosinate was found to be the least persistent herbicide, while trifluralin persisted the longest. The overall order of persistence was Trifluralin > Glyphosate > Glufosinate. Trifluralin was found at lower depths (0.15–0.30 cm) at 7 and 20 days after the herbicide application, with higher residual concentrations than the other herbicides used in the HR canola.

Abiotic stress QTL in lettuce crop-wild hybrids: comparing greenhouse and field experiments.

The development of stress-tolerant crops is an increasingly important goal of current crop breeding. A higher abiotic stress tolerance could increase the probability of introgression of genes from crops to wild relatives. This is particularly relevant to the discussion on the risks of new GM crops that may be engineered to increase abiotic stress resistance. We investigated abiotic stress QTL in greenhouse and field experiments in which we subjected recombinant inbred lines from a cross between cultivated Lactuca sativa cv. Salinas and its wild relative L. serriola to drought, low nutrients, salt stress, and aboveground competition. Aboveground biomass at the end of the rosette stage was used as a proxy for the performance of plants under a particular stress. We detected a mosaic of abiotic stress QTL over the entire genome with little overlap between QTL from different stresses. The two QTL clusters that were identified reflected general growth rather than specific stress responses and colocated with clusters found in earlier studies for leaf shape and flowering time. Genetic correlations across treatments were often higher among different stress treatments within the same experiment (greenhouse or field), than among the same type of stress applied in different experiments. Moreover, the effects of the field stress treatments were more correlated with those of the greenhouse competition treatments than to those of the other greenhouse stress experiments, suggesting that competition rather than abiotic stress is a major factor in the field. In conclusion, the introgression risk of stress tolerance (trans-)genes under field conditions cannot easily be predicted based on genomic background selection patterns from controlled QTL experiments in greenhouses, especially field data will be needed to assess potential (negative) ecological effects of introgression of these transgenes into wild relatives.

Investigations on plant functional traits, epidermal structures and the ecophysiology of the novel bioenergy species Sida hermaphrodita Rusby and Silphium perfoliatum L.

A growth experiment was performed with different accessions of the novel bioenergy species Sida hermaphrodita Rusby (Fanpetals, Malvaceae) and Silphium perfoliatum L. (Cup Plant, Asteraceae) to study differences between the perennial shrubs and the variation among biotypes. Non-destructive assessments (phenology, leaf numbers, height, SPAD and gas exchange) and several harvests were conducted to examine growth, allometry and the quality of shoot material (C:N, raw ash, protein, fibre, fat, calorific value and leaf δ 13 C). In addition to the functional analyses, epidermal structures of two widely used accessions were addressed to give insight into anatomical properties of the species . In the establishment phase, productivity was higher on average in S. hermaphrodita than in S. perfoliatum since latter remains in the rosette stage in the first year. While the accessions of S. hermaphrodita did not significantly differ in growth, functional traits and forage quality, S. perfoliatum showed large biotypic variation. Leaf water and ash contents, raw protein and fat levels were higher in latter species, while raw fibre contents were twice as high in S. hermaphrodita . At the end of the season, the calorific value of senesced stems of S. hermaphrodita proved to be higher than that of senesced leaves of S. perfoliatum pointing to its suitability of as a solid fuel. Despite the shorter longevity, lower SPAD and smaller size, the delicate leaves of S. hermaphrodita had more stomata, higher photosynthetic rates and higher stomatal conductances than the robust leaves of S. perfoliatum . Less negative δ 13 C signatures in S. perfoliatum (-27.3 ‰) compared to S. hermaphrodita (-30.24 ‰), point to the potentially higher water use efficiency of S. perfoliatum . Further investigations on the relationships between leaf properties, carbon acquisition and stomatal conductance under dry conditions may serve to select productive lines of the bioenergy species on marginal land thus avoiding conflicts with the farming of food crops. Normal 0 21 false false false DE X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Normale Tabelle; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;}

恩施烟区无翅桃蚜在烤烟田空间动态的地统计学分析

PDF HTML阅读 XML下载 导出引用 引用提醒 恩施烟区无翅桃蚜在烤烟田空间动态的地统计学分析 DOI: 10.5846/stxb201303270535 作者: 作者单位: 西南大学植物保护学院,湖北省烟草公司恩施州公司,湖北省烟草公司恩施州公司,湖北省烟草科学研究所,西南大学植物保护学院 作者简介: 通讯作者: 中图分类号: 基金项目: 湖北省烟草公司科技项目（027Y2010-032） Geostatistical analysison spatial dynamics of the apterous Myzus percicae in flue-cured tobacco fields of Enshi tobacco area, China Author: Affiliation: Plant Protect College in South-West University,Chong Qing,Enshi Prefecture Company of Hubei Provincial Tobacco Corporation,Enshi,Enshi Prefecture Company of Hubei Provincial Tobacco Corporation,Enshi,Tobacco Scientific Institute of Hubei Province,Wuhan,Plant Protect College in South-West University,Chong Qing Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:恩施烟区是湖北省最大烟叶生产基地，桃蚜Myzus percicae （Sulzer）是恩施烟叶最重要的害虫之一，桃蚜在田间的发生以及传播的病毒病害逐年加重，给烟业生产带来巨大损失。进一步了解桃蚜发生动态和空间分布规律，将提高对桃蚜的预测效果并为其综合防治提供理论依据。烟区和烟田之间的迁移以有翅蚜为主，田块内部的种群动态和发生规律，无翅桃蚜发挥着更加重要的作用。受寄主生理生化特性影响，不同烟叶生育期，桃蚜空间结构的差异需要进一步验证。经典的统计学方法以纯随机变量为基础，而昆虫种群的田间分布存在空间相关性，地学统计学承认空间相关性的存在，为区域化变量的空间分布分析提供新的理论和方法。在烟叶不同生育期进行无翅桃蚜的田间密度调查，运用地统计学的方法分析了其空间特征和发生动态，模拟了无翅桃蚜在烟叶不同生育期的田间分布图，并对无翅桃蚜在不同烟叶生育期田间分布格局的相关性进行了分析。结果表明：无翅桃蚜在烟叶苗期密度最小为（5.59±4.07）头/株，烟叶旺长期虫口密度最大为（14.5±9.6）头/株；种群密度变异系数均较大（0.6147-0.7281），表明其空间分布的不均匀性，并随密度的增大而减小，表明种群密度的增大一定程度上提高了种群结构的稳定性。烟叶苗期的种群分布曲线峰度最大，表现出更高的聚集性。无翅桃蚜在烟叶苗期的135°方向和团棵期的45°方向表现为随机分布。烟叶苗期的0°方向和45°方向可用线性有基台模型拟合，其他均可用球形+指数套合模型拟合，判断球形+指数套合模型是无翅桃蚜田间分布的主要模型，属于聚集型分布的范畴。块金值、基台值和变程均随田间虫口密度的增大而增大，苗期的随机程度（0.1905-0.7186）明显大于其他时期（0.0116-0.1620）。无翅桃蚜空间分布模拟图可以清晰地看出无翅桃蚜苗期迁移，旺长期后逐渐稳定的特性。无翅桃蚜的田间分布在烟叶苗期与团棵期无明显相关性，而团棵期与旺长期以及旺长期与成熟期显著相关，再次证明烟叶苗期到团棵期，无翅桃蚜的田间分布发生较大迁移，而团棵期以后基本定殖。烟叶苗期的无翅桃蚜高度聚集在少数烟株上，及早预防可以减少烟叶苗期虫口基数，有利于桃蚜种群数量的控制。首次将平面坐标系划分为4个方向，更加准确、全面地描述昆虫种群的空间分布特征。 Abstract:The Enshi area is the largest tobacco growing base in Hubei Province, China, and the peach aphid, Myzus percicae (Sulzer), is one of the most important pests of tobacco leaves in this region. The prevalence of peach aphid populations is increasing rapidly, as are incidents of viral disease spread by these insect pests, both of which result in substantial losses to tobacco production. More research on the spatial distribution and development of peach aphids will enhance the ability to predict its occurrence and comprehensively manage its populations. The alate form of the aphid migrates between tobacco fields and areas, whereas the population dynamics and occurrence cycles depend more on the insect's apterous type. Because the spatial structure of peach aphid populations in tobacco fields depends on the host's physiological and biochemical characteristics at different growth stages, more research is required to fully understand it. Classical statistical methods assume a random distribution, but insect populations show strong spatial correlation in the field. Newly-developed geological statistical methods can accommodate spatial correlation, allowing analyses of the spatial distribution of regionalized variables. We investigated the density of apterous peach aphids in tobacco fields at the seedling, rosette, rapid-growth, and maturity stages of growth and used geostatistical methods to analyze the spatial features and development of the insect, to simulate its distribution at different stages of tobacco, and to analyze the correlation between its spatial distribution during different stages of tobacco. The results showed that the aphid density was lowest at the tobacco seedling stage ((5.59 ± 4.07) aphids per plant) and peaked at the rapid-growth stage ((14.5 ± 9.6) aphids per plant). The variable coefficient of the density was relatively large (0.6147-0.7281), which indicated the inhomogeneity of the spatial distribution. The coefficient decreased as the population density increased, which showed that the population structure stabilized at higher densities. The largest kurtosis in the spatial pattern occurred at the seedling stage of tobacco, indicating more spatial clustering. We divided the plane into four directions (0°, 45°, 90°, and 135°) and found that the spatial distribution of aphids in the 135° direction during the seedling stage and the 45° direction during the rosette stage were randomly distributed. In the 0° and 45° directions during the period, the distributions matched linear models with a base station, and all other distributions fitted nested models with spherical + exponential factors. Therefore, we deduced that the primary model for apterous M. persicae was the latter, indicating an aggregated distribution. All nuggets, stills, and ranges increased with density. The random degree of the model in the seedling stage (0.1905-0.7186) was significantly greater than in other stages (0.0116-0.1620). Kriging interpolation clearly described the migration in the seedling stage and showed that the spatial distribution was relatively stable in the other three stages. The spatial pattern of apterous peach aphid in the seedling stage of tobacco had no correlation with that in the rosette stage, but there was an obvious correlation between the rosette and rapid-growth stages and also between the rapid-growth and maturity stages. This indicated that migration should occur during the seedling stage and that the population distribution should remain relatively stable afterwards. We demonstrated that dividing the plane coordinate into four directions made the description of the spatial distribution more accurate and comprehensive. 参考文献 相似文献 引证文献