Showing papers on "Plant morphology published in 1999"

Towards an organismic concept of land plants: The marginal blastozone and the development of the vegetation body of selected frondose gametophytes of liverworts and ferns

Abstract: An organismic concept of land plants is outlined, which is based on a synthesis of plant morphology and plant anatomy. The entire plant, the living unity, is conceived as the organism being subdivided into cells, which cannot be interpreted as organisms themselves in the sense of elementary organisms. The evolution of land plant tissue systems is discussed in the introductive chapter. To test the proposed concept, some frondose plants were selected from liverworts (Pellia epiphylla, Metzgeria furcata, Pallavicinia lyallii) and comparable fern gametophytes (Dryopteris filix mas, Vittaria lineata, Stenochlaena tenuifolia) and studied with respect to their organization and the principles of development. They all have an archetypic, two-dimensional, open construction, which is described as the “repens-type” of plant construction. Primary form growth occurs in the marginal blastozone, which controls cell wall integration. One of the most significant processes of form generation is blastozone fractionation. The tissues leaving the blastozone differentiate during extension growth and maturation of the vegetation body. While the plant grows continuously in the blastozone, it decays steadily in the necrozone. The implications of the two-dimensional repens-type are discussed. It appears as a perfect plant construction, fit to start plant evolution on the land surface. Growing upwards into the atmosphere, the repens-type is obscured. But is reappears in all groups of higher land plants. This demonstrates the existence of evolutionary cycles in plants. It is argued that mutation and selection do not suffice to understand cyclical evolutionary patterns. The influence of organismic construction seems to predetermine evolution because of the limited options to change an appropriately functioning construction. Via construction analysis evolutionary options can be detected and thus, evolution becomes predictable to some extent. Instead of being object of mutation and selection, living organisms should be conceived as subjects in evolution (Weingarten 1993).

Pollenizer plants for use in the production of seedless watermelon

Abstract: This invention relates to a pollenizer watermelon plant, for use in the production of seedless watermelon. The pollenizer plant is characterized by at least two of the following features: (a) distinguishable fruit phenotype; (b) high number of male flowers; (c) continued flowering; (d) early flowering; and/or (e) modified plant morphology and growth habit. The invention particularly relates to plants having the characteristics of plants grown from the seed deposited at the ATCC under ATCC accession number 203691. The invention further relates to plants obtainable by propagation of, and/or breeding with a watermelon plant grown from the seed deposited at the ATCC under ATCC accession number 203961.

Plant morphology, environment, and leaf area growth in wheat and maize

Abstract: Leaf area expansion of wheat (Triticum aestivum L.) and maize (Zea mays L.) plants, as contrasting representatives of the Gramineae family, was analysed. Seven variables were identified that together completely determine leaf area expansion of the plant: leaf appearance rate per tiller, specific site usage (fraction of buds that ultimately develop into a visible tiller at a specific site), Haun Stagedelay (indicating the timing of tiller appearance relative to the parent tiller), leaf elongation rate, leaf elongation duration, maximum leaf width and a leaf shape variable. Experiments with spaced plants in growth chambers yielded equations in which the effects of leaf and tiller position, temperature and photosynthetic photon flux density (PPFD) were quantified for each leaf area variable. In non-tillering species maize, leaf appearance rate and leaf elongation rate were higher, and leaf elongation duration was shorter at higher temperatures. At higher PPFD values, leaf appearance rate and maximum leaf width were higher and leaf elongation rate was lower. In wheat, the effects of temperature and PPFD were qualitatively equal to those in maize, except that there was no effect of PPFD on maximum leaf width. In the tillering species wheat, specific site usage was higher at lower temperatures and higher PPI'D values. Equations were developed for the effects of leaf position on leaf elongation rate and maximum leaf width. This knowledge was used in the analysis of effects of plant density in growth chamber and field experiments. Plant density mainly affected leaf appearance rate in maize and specific site usage in wheat. For both species, the effects of plant density on these variables seemed well related to local assimilate availability. Based upon the morphological framework presented, a simulation model was developed for wheat using the principles of object orientation. Plant related processes were strictly simulated at organ level. The simulation results showed clear differences in leaf area expansion for leaves at different positions in the plant. The morphological framework can be used for experimental analysis of leaf area growth, revealing mechanisms regulating leaf area growth of plants. The simulation model is flexible and can be easily extended for different environmental conditions and plant species.

Gain from Two Cycles of Divergent Selection for Root Morphology in Alfalfa

Abstract: Alfalfa (Medicago sativa L.) has been identified for use in phytoremediation. Phytoremediation is defined as the use of green plants to remove or contain environmental contaminants. Alteration of root morphology would increase the degradative efficiency of alfalfa for phytoremediation. Root morphology traits in alfalfa are heritable, but are strongly influenced by dormancy and geographic origin. Our objective was to create alfalfa source germplasms that differ in root morphology within the same genetic background. Four experimental alfalfa germplasms differing in dormancy and genetic origin were evaluated after two cycles of divergent selection for root morphology traits. Two sources were selected for few vs. many lateral roots and the other two sources were selected for few vs. many fibrous roots followed by one subsequent cyde of selection for few vs. many lateral roots. These divergent populations were evaluated using two fertilizer rates (0 and 200 kg N ha -1 ) and were established twice at each of two locations. Plants from one experiment at each location were dug at the end of the establishment year and from the second experiment at the end of the first production year. All plants were evaluated for number of lateral roots, fibrous root mass, taproot diameter, plant count per plot, and plot root weight. Two cycles of divergent selection for root morphology traits in all four source germplasms produced alfalfa populations that differed in root morphology. Realized heritabilities from all germplasm sources ranged from 21 to 48% for fibrous root mass and from 11 to 43% for lateral root number. Response to selection varied among the four source germplasms and indicated that the choice of parent germplasm will be a factor for success in producing alfalfa populations that differ in root morphology within a single genetic source.

Variation in leaf structure: an ecophysiological perspective.

Abstract: 1. Biotic And Abiotic Consequences Of Differences In Leaf Structure 2. A Mechanical Perspective On Foliage Leaf Form And Function 3. Modelling Leaf Expansion In A Fluctuating Environment: Are Changes In Specific Leaf Area A Consequence Of Changes In Expansion Rate? 4. Specific Leaf Area In Barley: Individual Leaves Versus Whole Plants 5. Leaf Structure And Specific Leaf Mass: The Alpine Desert Plants Of The Eastern Pamirs, Tadjikstan 6. Contribution Of Carbohydrate Pools To The Variations In Leaf Mass Per Area Of Tomato Leaves 7. Leaf Structure And Chemical Composition As Affected By Elevated CO2: Genotypic Responses Of Two Perennial Grasses 8. The Relationship Between Leaf Composition And Morphology At Elevated CO2 Concentrations 9. Profiles Of Photosynthetic Oxygen Evolution Within Leaves Of Spinacia Oleracea 10. Leaf Anatomy Enables More Equal Access To Light And CO2 Between Chloroplasts 11. Assessing Leaf Pigment Content And Activity With A Reflectometer 12. Relationships Between Photosynthesis, Nitrogen And Leaf Structure In 14 Grass Species And Their Dependence On The Basis Of Expression 13. Low-Light Carbon Balance And Shade Tolerance In The Seedlings Of Woody Plants: Do Winter Deciduous And Broad-Leaved Evergreen Species Differ? 14. Specific Leaf Area And Leaf Dry Matter Content As Alternative Predictors Of Plant Strategies 15. A Comparison Of Specific Leaf Area, Chemical Composition And Leaf Construction Costs Of Field Plants From 15 Habitats Differing In Productivity 16. Leaf Life Span And Nutrient Resorption As Determinants Of Plant Nutrient Conservation In Temperate-Arctic Regions 17. Leaf Structure And Defence Control Litter Decomposition Rate

Changes in the canopy structure of the Mediterranean shrub Lavandula stoechas after disturbance

Abstract: . This study attempts to show the dynamics of the canopy structure of the Mediterranean pioneer shrub Lavandula stoechas after man-made perturbation (i.e. grazing). The development of the vertical structure of the shrub was studied by harvesting the canopy of plants of 2–6 yr old in horizontal layers. The supportive biomass of the canopy was concentrated near the base at all ages. Leaf biomass was evenly distributed all over the vertical profile in 2- and 3-yr old plants. In 4-yr old plants it presented a maximum near the top of the canopy. For 5-yr old plants a structural transition started with leaf profiles showing a bimodal distribution. Leaf biomass predominated near the base in 6-yr old plants, suggesting that the transition was completed. Three canopy stages in the growth processes of the plant were recognized after the first year of growth: in the first one (from 2 to 3 yr old) both leaf and supportive biomass increased; in the second one (from 3 to 4 yr) leaf biomass remained stable and there was an increase in supportive biomass until the plants reached a ‘mature stage’, in 4-yr old plants; finally, in 5- and 6-yr old plants there was a decrease both in leaf and supportive biomass and plant structure showed evidence of senescence. Early transitions from seedling to 1-yr old plant and from this to 2- to 3-yr old plants were less obvious. The leaf/supportive biomass ratio always decreased with plant age, from 1.88 in seedlings to 0.01 in 6-yr old plants. Biomass density followed the pattern of supportive biomass, with an increase from 1.7 g/dm3 (2-yr old plants) to 2.4 g/dm3 (4-yr old plants). Thereafter, biomass density decreased to 0.6 g/dm3 (6-yr old plants).

Edible Sprout Production from Ainsliaea acerifolia Seeds

Abstract: This study was carried out to investigate the morphological characteristics of the plants and seeds of Ainsliaea acerifolia and to determine the optimum condition for producing sprouts from the seeds. Plant height, flower stalk length, and pod number were higher in natural habitat than in campus farm. Average 1.2 seeds per pod was set but only 0 to 2 seeds per plant was set in plants with the enveloped flower stalks, indicating that this is an outcrossing species. Most of seeds were 9-11㎜ long and 1.1-1.4㎜ wide. Fresh weight of seeds was ranged from 10㎎ to 17㎎. Seeds germinated well at 15℃ and 20℃. Mean germination period was 11.5 day at 15 to 25℃. Sprouts grown at 15℃ was longest(5.4㎝) and heaviest(738㎎/10 sprouts). Chlorophyll content was 333㎎ per fresh weight 100g. Protein, Fe, vitamin B1, vitamin B2, and vitamin C were respectively 23.7㎎, 6.4㎎, 1.82㎎, 0.49㎎, and 10.7㎎.