Two new naturalized species from Korea, Amaranthus hybridus and Crepis tectorum

2005 ◽  
Vol 35 (3) ◽  
pp. 201-209 ◽  
Author(s):  
You Mi Lee ◽  
Su Hyun Park ◽  
Jae Min Jeong
Keyword(s):  
Amaranthus Hybridus ◽  
Crepis Tectorum

scholarly journals Thrips (Thysanoptera) of vegetable crops (okro, spinach, garden egg and pumpkin) grown in Southeastern Nigeria

2011 ◽  
Vol 39 (No. 4) ◽  
pp. 132-138 ◽  
Author(s):  
E.T. Oparaocha ◽  
R.N. Okigbo
Keyword(s):  
Lower Number ◽  
Frequency Of Occurrence ◽  
Vegetable Crops ◽  
Southeastern Nigeria ◽  
Amaranthus Hybridus ◽  
Solanum Incanum ◽  
Telfairia Occidentalis ◽  
Port Harcourt ◽  
Microscopic Studies ◽  
Hibiscus Esculentus

Eight vegetable crops were sampled at five localities in Southeastern Nigeria and were found to harbour one or more species of thrips. The crops were Amaranthus hybridus, A. spinosus, Basella rubra, Solanum incanum, S. melongena, Hibiscus esculentus, Telfairia occidentalis and a species of Solanum. The sampled localities, with the frequency of occurrence of thrips, were Umuahia (29.6%), Owerri (28.5%), Port Harcourt (25.7%), Calabar (18.7%) and Enugu (6.0%). The studies revealed that crops with very heavy infloresences, e.g. Amaranthus hybridus, had a higher number of thrips (40%) per flower/leaf, while simple flowered crops like Telfairia occidentalis could only harbour a far lower number of thrips per flower/leaf. This showed a preference of these thrips for plants with heavy inflorescences which provided them with more protection, especially their larvae. Taxonomic/microscopic studies identified three species of thrips: Haplothrips gowdeyi that attacked 63% of all the sampled crops, Frankliniella schultzei was hosted by 50% of the crops, and Megalurothrips ventralis also preyed on 50% of the plant samples.  

Interaction of Photosystem II Herbicides with Bicarbonate and Formate in Their Effects on Photosynthetic Electron Flow

1984 ◽  
Vol 39 (5) ◽  
pp. 374-377 ◽  
Author(s):  
J. J. S. van Rensen
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Hill Reaction ◽  
Amaranthus Hybridus ◽  
Apparent Affinity ◽  
Photosynthetic Electron Flow ◽  
Different Characteristics ◽  
The Hill

The reactivation of the Hill reaction in CO2-depleted broken chloroplasts by various concentrations of bicarbonate was measured in the absence and in the presence of photosystem II herbicides. It appears that these herbicides decrease the apparent affinity of the thylakoid membrane for bicarbonate. Different characteristics of bicarbonate binding were observed in chloroplasts of triazine-resistant Amaranthus hybridus compared to the triazine-sensitive biotype. It is concluded that photosystem II herbicides, bicarbonate and formate interact with each other in their binding to the Qв-protein and their interference with photosynthetic electron transport.

Phenotypic selection in a population of Crepis tectorum ssp. pumila (Asteraceae)

1992 ◽  
Vol 70 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Stefan Andersson
Keyword(s):  
Life History ◽  
Multiple Regression ◽  
Large Scale ◽  
Demographic Data ◽  
Phenotypic Selection ◽  
Direct Selection ◽  
Surprising Result ◽  
Regression Analyses ◽  
Ecotypic Differentiation ◽  
Crepis Tectorum

A 3-year demographic study was conducted to reveal targets of selection on morphology and life history in a population of Crepis tectorum ssp. pumila, a winter annual plant confined to calcareous grasslands (alvars) on the Baltic island of Öland (south Sweden). I calculated the selection differential to describe the change in the mean value of a character due to selection and used multiple regression analyses to partition the direct effect of selection on the trait from indirect responses of selection on other traits. Rosette leaf number, a convenient measure of plant size, was strongly correlated with both viability and fertility (fitness). There was also a strong relationship between fitness and the extent to which the plants expressed traits characterizing this particular taxon. Multiple regression analyses indicated direct selection favouring plants with deeply lobed leaves and a densely branched stem, two distinctive traits of ssp. pumila believed to be adaptive in the alvar habitat. Only stem height was subject to both direct and indirect selection in the wrong direction; taller individuals were more successful than those with a shorter stem, a surprising result considering the inferred advantage of a short stature in the exposed alvar habitat. Selection on other traits assumed to be ecologically important (germination time, flowering time, and seed size) was found to be either absent or variable in direction when other traits were held constant. The failure of plants to survive to the flowering stage in the last two summers indicates strong selection for plants that produce a high percentage of dormant seeds. Overall, the contemporary selection regime as revealed by demographic data was only partly congruent with predictions regarding historical selection pressures based on large-scale patterns of variation (ecotypic differentiation). Key words: Crepis tectorum, ecotypic differentiation, life history, morphology, phenotypic selection.

Growth of Amaranthus Hybridus (African Spinach) under diffferent Daylight Intensities in the Dry Season in Southern Nigeria

1987 ◽  
Vol 23 (2) ◽  
pp. 193-200 ◽  
Author(s):  
J. M. O. Eze
Keyword(s):  
Light Intensity ◽  
Biochemical Parameters ◽  
Dry Matter ◽  
Maximum Growth ◽  
Area Ratio ◽  
Dry Matter Accumulation ◽  
Amaranthus Hybridus ◽  
Maximum Accumulation ◽  
Southern Nigeria ◽  
Reduced Light

SummaryThe growth of Amaranthus hybridus under different daylight intensities was assessed in terms of physical, morphological and biochemical parameters. Maximum growth in many respects was achieved at about 70% of full daylight. However, full daylight favoured chlorophyll stability and maximum accumulation of total dry matter, carbohydrate, chlorophyll and ascorbic acid. The leaf area ratio increased uniformly with decrease in light intensity. Ageing was accelerated by full daylight. Reduced light intensity reduced dry matter accumulation in the roots more than in the stems or leaves.

scholarly journals Seleção de plantas com potencial para fitorremediação de tebuthiuron

2003 ◽  
Vol 21 (3) ◽  
pp. 451-458 ◽  
Author(s):  
F.R. Pires ◽  
C.M. Souza ◽  
A.A. Silva ◽  
M.E.L.R. Queiroz ◽  
S.O. Procópio ◽  
...  
Keyword(s):  
Raphanus Raphanistrum ◽  
Amaranthus Hybridus ◽  
Crotalaria Juncea ◽  
Pennisetum Typhoides ◽  
Helianthus Annus

Este trabalho teve como objetivo selecionar espécies tolerantes ao tebuthiuron, visando utilizá-las em programas de fitorremediação de solos contaminados com esse herbicida. Foram avaliadas: Amaranthus hybridus, Crotalaria juncea, Chamaesyce hyssopifolia, C. hirta, Canavalia ensiformes, Helianthus annus, Pennisetum typhoides, Estizolobium aterrimum, Raphanus raphanistrum e Crotalaria incana. O experimento foi conduzido em casa de vegetação, em vasos contendo 3 dm³ de solo de textura argilo-arenosa com 2,18 dag kg¹ de matéria orgânica. O experimento foi delineado em blocos ao acaso, com três repetições de tratamentos em fatorial 10 x 4 x 4, os quais foram constituídos por 10 espécies, quatro doses de tebuthiuron (0,0; 5,0; 1,0; e 2,0 kg ha-1), aplicadas em pré-emergência, e quatro épocas de avaliação (15, 30, 45 e 60 dias após a semeadura). Foram avaliadas a fitotoxicidade do herbicida, a altura de plantas e a massa de matéria seca da parte aérea, de raízes e do total da planta. Canavalia ensiformes e Pennisetum typhoides foram tolerantes ao tebuthiuron na dose de 0,5 kg ha-1. Estizolobium aterrimum tolerou tebuthiuron até a dose de 1,0 kg ha¹, apresentando fitotoxicidade menos acentuada e menor redução de altura de plantas e da massa de matéria seca da parte aérea, de raízes e do total da planta em relação ao tratamento testemunha.

Seed size as a determinant of germination rate in Crepis tectorum (Asteraceae): evidence from a seed burial experiment

1996 ◽  
Vol 74 (4) ◽  
pp. 568-572 ◽  
Author(s):  
Stefan Andersson
Keyword(s):  
Seed Size ◽  
Germination Rate ◽  
Local Population ◽  
Seed Viability ◽  
Seed Burial ◽  
Small Seed ◽  
Crepis Tectorum ◽  
Winter Annual ◽  
Selection For ◽  
The Relationship

The present study of the winter annual Crepis tectorum examines the relationship between seed (achene) size and the extent to which seeds resist germination during the year of their production. I carried out two seed burial experiments, one at an outcrop site occupied by a small-seeded population, and another in an experimental garden with soil from the same field site, with seeds representing the local population and a segregating generation of a cross between two other populations. Using logistic regression with data corrected for seed viability, I found an association between small seed size and failure to germinate in the first autumn. The small seed size characterizing many outcrop populations may have evolved as a response to selection for delaying germination in a habitat subject to unpredictable droughts during the growth season. Keywords: Crepis tectorum, germination, seed bank, seed size.

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