Maranta nanica (Marantaceae), a new dwarf species from Central Brazil

A new species of Maranta (Marantaceae) from Central Brazil is described and illustrated. The species is recognizable due to its small rosulate habit, unbranched aerial shoot, hirtellous bracts with apex acute, sub-brachyblastic cymules, and each bracteole subtending a single flower.

Shading on Yield and Quality of Lettuce Cultivars in Semiarid Conditions

Lettuce is a crop originating from temperate climate, and for this reason, when cultivated in semiarid region, characterized by high luminosity and temperature, major losses in productivity and quality occur. The objective of this work was to evaluate the influence of different levels of shade on yield and quality of lettuce cultivars in semiarid conditions. The experiment was conducted under field conditions at the Human and Agricultural Sciences Center at State University of Paraiba, Brazil, in randomized blocks with parcels divided into 4 × 4 factorial space, and four repetitions. The parcels received different shading levels (0, 30, 50 and 70%) with black polypropylene screen and sub parcels by lettuce cultivars: ‘Americana Irene’, ‘White Boston’, ‘Regina de Verão’ and ‘Green Salad Bowl’. The shading promoted higher performance in height, stem diameter, root length, pH and dry mass of lettuce plants when compared to those grown in the open-air, being the shading of 70% the more efficient. The ‘Americana Irene’ cultivar was distinguished in terms of plant height, foliage area, leaves dry mass and soluble solids, independently from the cultivation environment. With the shading, this cultivar improved the aerial shoot-root ratio and root dry mass.

Нангиад зээргэний (EphedrasinicaStapf.) биохимийн судалгаа

We have determined some biochemical properties including the moisture, ash, protein, nitrogen, cellulose, lignin, lipids and fatty acids in aerial shoot systems and root systems of the Ephedra sinica Stapf. From the test results, cellulose contents were 19.12% in aerial shoot systems and 20.23% in root systems. Thus, this indicates that the aerial shoot systems of Ephedra sinica Stapf. are promising raw materials to synthesize polysaccharides.Lipid and lipid like substance components in seeds, aerial shoot systems and root systems of the Ephedra sinica Stapf. Seed contain 71.39% of all lipid and lipid like substances other origins of Ephedra sinica Stapf contain comparatively minimum amount of all lipids. From the study of fatty acids was contained in Ephedra sinica Stapf we identified nine different fatty acids in which the biologically active fatty acids, linoleic acid was contained up to 42% in aerial shoot systems. It is possible to use it for medical treatments because it is a major ingredient in F vitamin.Analysis of amino acid contents was carried out by thin layer chromatography. As a result, total of 15 amino acids including all non substituted amino acids were identified. Metionin content (12.5%) was higher than any other amino acids in Ephedra sinica Stapf.

Purple Nutsedge (Cyperus rotundus) Tuber Production and Viability Are Reduced by Imazapic

Weeds exploit underutilized space, causing economic losses in cropping systems. Weed management tactics alter that underutilized space until the crop can mature and efficiently use that space. One tactic is to reduce the weed propagules (e.g., seeds and tubers) that persist quiescently in the soil, which includes minimizing production and addition of new propagules to the soil. Purple nutsedge is a problematic weed around the globe, persisting between growing seasons as tubers in the soil. Imazapic is a peanut herbicide often used in Georgia for control of purple nutsedge. The objective of the experiment was to evaluate the effect of various rates of imazapic on purple nutsedge tuber production. Single presprouted purple nutsedge tubers were transplanted into outdoor microplots and treated after 6 wk of growth with six rates of imazapic (5 to 140 g ai ha−1) POST. A nontreated control was included. All emerged shoots at the time of application were marked with plastic rings; this allowed for classification of tubers at exhumation as (1) tubers attached to shoots that were emerged at time of application, (2) tubers attached to shoots that emerged after application, and (3) tubers without an aerial shoot during the study. At 7 wk after application, the tubers in the microplots were exhumed, classified, and quantified, and their ability to sprout was evaluated. In the nontreated control, there were 544 total tubers, with a log-logistic regression model describing the declining tuber population with increasing imazapic rate. The rate of imazapic that reduced total tuber population 50% (I50) was 36 g ha−1. In the nontreated control, there were 161 tubers attached to shoots that emerged, as when compared with plots that received an imazapic application that had an I50=60 g ha−1. Viability of purple nutsedge tubers was 44% at 70 g ha−1imazapic, suggesting the action of the herbicide may have rendered the tubers nonviable after new shoots were produced. The final classification of tubers included those that did not have an aerial shoot during the study. These were tubers in which apical dominance suppressed shoot development or were likely the most recent tubers to develop. Of the three classes, the tubers without shoots were the most prevalent in the nontreated control, with 358 tubers and an I50=18 g ha−1. Imazapic controls purple nutsedge foliage but also reduces the number of new tubers produced, and overall tuber viability and is a valuable tool in management of the long-term population density of this weed.

Halosulfuron Reduced Purple Nutsedge (Cyperus rotundus) Tuber Production and Viability

Weeds persist and cause economic losses in agricultural systems because they exploit underused portions of that system. Reducing the effect of weeds on agroecosystems begins with minimizing the number of propagules (e.g., seeds and tubers) that are produced and returned to the soil. Purple nutsedge is a problematic weed around the globe, persisting between growing seasons as tubers in the soil. Halosulfuron is an effective herbicide for controlling purple nutsedge foliage and is used in corn and several vegetable crops. Studies were conducted to evaluate the effect of various rates of halosulfuron on purple nutsedge tuber production. Single, presprouted purple nutsedge tubers were transplanted into outdoor microplots and treated after 6 wk of growth with six rates of halosulfuron (7 to 208 g ai ha−1) POST with a nontreated control (NTC). All shoots that had emerged at the time of application were marked with plastic rings; this allowed for classification of tubers at exhumation of (1) tubers attached to shoots that had emerged by the time of application, (2) tubers attached to shoots that emerged after application, and (3) tubers without an aerial shoot during the study. Seven weeks after application, the tubers in the microplots were exhumed and tubers were classified, quantified, and their ability to sprout was evaluated. In the NTC, there were 530 total tubers, with a log-logistic regression model describing the tuber population with increasing halosulfuron rate. The rate of halosulfuron that reduced total tuber population 50% (I50) was 8 g ha−1. In the NTC, 200 tubers were attached to shoots that emerged following halosulfuron application, and this class of tubers had anI50of 19 g ha−1. Viability of tubers with shoots that emerged following halosulfuron application was 28% at the 52 g ha−1halosulfuron, suggesting the action of the herbicide may have rendered the tuber nonviable after new shoots were produced. The final classification of tubers was those that did not have an aerial shoot during the study. These were tubers in which apical dominance suppressed shoot development or were likely the most-recent tubers to develop. Of the three classes, the tubers without shoots were the most numerous in the NTC, with 294 tubers and anI50of 1 g ha−1. Halosulfuron is an effective herbicide that not only controls purple nutsedge foliage but also reduces the number of new tubers produced and overall tuber viability. This could be an important component to reduce the long-term population density of the weed.

Effect of growth retardants, cytokinins and auxins on the multiplication and rooting in vitro of Alstroemeria x hybrida "Juanita"

Rhizome cultures of "Jiianita" Polish cultivar of Alstroemeria x hybrida were used to enhance an effectiveness of micropropagation method of new cultivars and selections. The effect of cytokinins (BAP. kinetin and 2iP), auxins (IAA, IBAand NAA), growth retardants (paclobutrazol and flurprimidol alone or in combination were studied in relation to rhizome branching. aerial shoot production and rooting of rhizome. The greatest number of aerial shoots as well as the shortest shoots were observed at the highest BAP concentration (6 mg l^-1). However, the rhizonies had the poorest rooting ability. BAP at low concentrations combined with kinetin or 2iP also strongly stimulated aerial shoot formation and rhizome branching. Unfortunately. those shoots were of poor qualily. Application of BAP at low concentration with paclobutrazol (0,1-0,5 mg l^-1 ) or flurprimidol (0,01- 1 mg l^-1) in presence of 1 mg l^-1 NAA resulted in high number of aerial shoots (5-6), reduction of their length and higher rooting ability of the rhizomes. Gr()wth retardants applied with NAA strongly stimulated formation of the roots but suppressed their elongation. Abbreviations: BAP - 6=benzylaminopurine; kinetin - 6-furfurylaminopurine; 2iP - 6-‌γ,γ-dime-thylallylamino]purine); IAA-indole-3-acetic acid; IBA-indole-3-butyric acid; NAA- naphthaleneacetic acid; paclobutrazol (ICI PP-333) - (2-RS,3-RS)-1-(4-chlorophenyl)-4-4-dimethyl-2(1,2,3-triazol-1-yl)-pentan-3-ol flurprimidol (Dowelanco) - α-(1-niethylethy 1-α-[4-trifluro-niethoxy)phenyl]-5-pyridinemethanol.

Effect of the cereal cyst nematode, Heterodera filipjevi, on wheat in microplot trials

The cereal cyst nematodes, Heterodera avenae, H. filipjevi and H. latipons, are considered to be the most economically important species of cyst-forming nematodes on wheat. Two trials were conducted in 2006 and 2007 to determine the impact of different initial population levels of H. filipjevi (0, 2.5, 5, 10 and 20 eggs and second-stage juveniles (J2) (g soil)−1) on wheat cv. Sardari in microplots under natural field conditions in Iran. The results showed that increasing the initial populations of H. filipjevi significantly reduced several growth parameters of wheat (plant height, root dry weight, aerial shoot dry weight and grain yield) compared with the untreated controls. The final population of H. filipjevi increased with increasing initial population, while the reproduction factor (Rf) declined as the initial population increased but was greater than 1 in all treatments. Regression analysis showed a significant negative relationship between the initial populations and grain yield. The modelling clearly demonstrated that H. filipjevi is economically important on winter wheat in Iran. Grain yield loss was demonstrated even at the lowest population density and reached a maximum loss of 48% with an initial population density of 20 eggs and J2 (g soil)−1. The aerial shoot yield loss was as great as 40% in both years.

Timing of Nutrient Termination and Reapplication for Growth, Flower Initiation, and Flowering of the Nobile Dendrobium Orchid

Hybrids of Dendrobium nobile Lindl. have high potential to become a high-value pot plant, but detailed research to support the development of commercial production protocols was lacking. A 3 × 5 factorial experiment was conducted to investigate the effects of nutrient termination date (1 Aug., 1 Sept., or 1 Oct.) and nutrient reapplication time (at the beginning or in the middle of cooling, immediately after or 2 weeks after the completion of cooling, or no nutrient reapplication) on growth and flower development of Dendrobium Sea Mary ‘Snow King,’ a D. nobile hybrid. Interaction between nutrient termination date and reapplication time on growth and flowering was nonsignificant for all variables measured, and reapplication time had only a minor effect on leaves remaining. Regardless of nutrient reapplication time, delaying nutrient termination date resulted in improved growth and flowering. Nutrient termination on 1 Oct. resulted in taller plants with more nodes, leaves remaining, flowering nodes, and total flowers as well as fewer aborted flowers than an earlier termination date. Nutrient supply until 1 Oct. did not lead to differences in time required for anthesis but extended the time needed to reach full flowering by 1.5 d. The results suggest that flower development benefited more from the nutrients that were accumulated in mature pseudobulbs before nutrient termination rather than from those being taken from the reapplied fertilizers. Only lateral buds protruding 2 mm or more from the pseudobulb surface showed differentiated floral structures when examined histologically. The buds, excised 4 weeks after cooling treatments began, showed that nutrient termination on 1 Aug. resulted in larger flower primordia than those ended on 1 Oct., indicating an earlier or faster flower differentiation with earlier nutrient termination. No aerial shoot formation or reversion of reproductive to vegetative buds arose as a result of either late nutrient termination or resumption of nutrient application.