Showing papers on "Plant morphology published in 1993"
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01 Jan 1993
TL;DR: Early Silurian and Late Ordovician Environments. as discussed by the authors presents an approach to an understanding of early land plant evolution, including the Charophycean Algae and land plants.
Abstract: Early Silurian and Late Ordovician Environments. Approaches to an Understanding of Early Land Plant Evolution. The Charophycean Algae. Morphology, Ecology, and Physiology of Charophytes. Gaps Between Charophycean Algae and Land Plants. The Evolution of Plant Morphology: Cell Walls, Cytoskeleton, Cytokinesis, Intercellular Communication, and Histogenesis. Evolution of Plant Sexual Reproduction. The Origin of Plant Signal Transduction Systems, Phytohormones, Photomorphogenesis, and Secondary Metabolism. Land Plant Origins----A Summary. Literature Cited. Index.
234 citations
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TL;DR: To measure insect impacts on plant size as a function of herbivore loads, and to determine the mechanisms by which insect feeding affects plant growth, using the techniques of plant growth analysis, are measured.
Abstract: Many plants support both leaf— and sap—feeding insects, yet comparative studies of plant responses to different types of damage are rare. I compared the impacts of a leaf—chewing beetle (Trirhabda sp.), a xylem sap—feeding spittlebug (Philaenus spumarius), and a phloem sap—feeding aphid (Uroleucon caligatum) on growth of goldenrod (Solidago altissima). My goals were (1) to measure insect impacts on plant size as a function of herbivore loads, and (2) to determine the mechanisms by which insect feeding affects plant growth, using the techniques of plant growth analysis. Plants were grown outdoors in large pots, and insects were placed on them at a range of densities. A series of four whole—plant harvests was performed, with the final harvest occurring after 3 wk of insect feeding. Insect mass gain per plant was used as the basis for the comparison, since the insects differed greatly in size. Spittlebugs were the most damaging insect, beetles were intermediate, and no effects of aphid feeding were detected. After 3 wk of feeding, both spittlebugs and beetles reduced total leaf mass, total leaf area, and root mass, and the impact of the spittlebug was 5—6 times greater than that of the beetle. Spittlebug feeding also reduced the mass of the apical buds, stem mass, and the number of lateral stems, while beetle and aphid damage had no effect on these variables. Dry mass allocation to leaves, stems, and roots was generally not affected by insect feeding, resulting in smaller but proportionally similar plants by the end of the feeding period. Plant relative growth rates (dry mass increase per unit dry mass per day) were reduced by both spittlebugs and beetles but not aphids, and the impact of the spittlebug was more severe than that of the beetle. None of the insects affected net assimilation rates (dry mass increase per unit leaf area per day), indicating that the insects did not reduce plant growth by altering plant physiology. Instead, reductions in relative growth rates were explained by changes in plant morphology; feeding by both spittlebugs and beetles strongly reduced specific leaf area (leaf area/leaf mass). This reduction of leaf area relative to leaf mass was the mechanism by which both insects decreased plant relative growth rates. This result suggests an explanation for why simulated damage frequently fails to mimic damage by actual herbivores. When leaves are artificially removed by clipping there will be an immediate change in dry mass allocation patterns, but specific leaf area will not necessarily be affected.
110 citations
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TL;DR: There appear to be two processes involved in the reduction of the plant parameters: direct physical damage with portions of the plants detached, and physiological changes, which slow down vegetative growth rates.
Abstract: The relationship between responses of plants to trampling and their morphological characteristics was studied in a glasshouse experiment. Thirteen species with four different growth forms were used in this experiment. They were five tussock species.Chloris gayana, Eragrostis tenuifolia, Lolium perenne, Panicum maximum, andSporobolus elongatus; three prostate grasses,Axonopus compressus, Cynodon dactylon, andTrifolium repens, two herbaceous species,Daucus glochidiatus andHypochoeris radicata; and three woody species,Acacia macradenia, Acrotriche aggregata, andSida rhombifolia. These species were subjected to three levels of simulated trampling. For each species, measurements were taken of aboveground biomass, root biomass, leaf length, leaf width, leaf thickness, leaf number, broken leaf number and plant height. Overall, these measurements were greatest in the control plants, moderate in the level of light trampling, and the lowest in the level of heavy trampling. Biomass was used as a basis of the assessment of plant resistance to trampling. Three tussock species,Eragrostis tenuifolia, Lolium perenne, andSporobolus elongatus had a high resistance. Woody and erect herbaceous plants were more intolerant to trampling. There appear to be two processes involved in the reduction of the plant parameters: direct physical damage with portions of the plants detached, and physiological changes, which slow down vegetative growth rates. Plant height was found to be the most sensitive indicator of trampling damage.
80 citations
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TL;DR: Begonia × elatior plantlets, regenerated from leaf disk callus, showed differences in flower morphology, flower size, plant height, plant morphology and number of flowers per plant, while micropropagation of two MV1 somaclones of each experimental plant, selected for their desirable traits, stabilized in the MV2 and MV3 generations.
28 citations
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TL;DR: The results suggest that the highly regulated process of nodule formation was under the influence of seed derived factors, while the continued accumulation of nodules tissue was related to shoot growth.
Abstract: Lima bean (Phaseolus lunatus L.) cultivars vary widely in their growth habit and seed size. Preliminary experiments indicated that a large-seeded pole cultivar (King of the Garden) formed many more nodules than a small-seeded bush cultivar (Henderson). The relative importance of seed size and shoot mass in determining nodule number and mass was assessed in five lima bean cultivars differing in seed size and growth habit. Between cultivars, significant positive correlations between initial seed mass, plant weight and nodule number and mass were observed during the first four weeks after planting. Comparisons within cultivars indicated a strong correlation between nodule mass and shoot dry weight. The influence of plant morphology on nodule formation and mass was secondary to the effects of seed and shoot mass. As plants matured, the increase in nodule mass paralleled the increase in plant mass, while nodule number was relatively stable after day 18. These results suggest that the highly regulated process of nodule formation was under the influence of seed derived factors, while the continued accumulation of nodule tissue was related to shoot growth.
21 citations
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TL;DR: Three trends were consistent across all 3 years for plants established by transplanting: they were more massive, they had larger vertical fruiting planes, and they had more branches, which increase the difficulty of mechanical harvest and create the potential for more leaves and stems in the harvested product.
Abstract: Nontreated seed, primed seed, and transplants were compared for effects on stand establishment, plant morphology, and yield of paprika pepper ( Capsicum annuum L.). Nontreated seed was satisfactory for stand establishment, although primed seed had the potential to provide greater initial stands. When populations were made equal by thinning, there were few differences in stem and leaf dry weight, fruit yield, or plant morphology attributed to seed treatment. Generally, morphology of plants established by direct seeding was favorable for mechanical harvest. Using transplants did not result in higher marketable fruit yields than direct seeding in 2 of 3 years. When compared to plants established by direct seeding, three trends were consistent across all 3 years for plants established by transplanting: 1) they were more massive, 2) they had larger vertical fruiting planes, and 3) they had more branches. These traits increase the difficulty of mechanical harvest and create the potential for more leaves and stems (trash) in the harvested product. Thus, transplanting is not recommended for stand establishment of paprika pepper intended for mechanical harvest.
9 citations
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TL;DR: It is concluded that observations taken in spaced plantings of orchardgrass can be used to make inferences about relative differences in sward plantings for the traits studied.
Abstract: This study was conducted to determine effects and interactions of plant density on digestibility and plant morphology of diverse orchardgrass (Dactylis glomerata L) clones Propagules of ten orchardgrass clones with contrasting morphology from two maturity groups (inflorescence emergence differed by 8d) were evaluated in sward (0·15-m centres) and spaced (0·60-m centres) plantings Plants were harvested from spring growth on a common date near anthesis and from summer growth when about 5 weeks of forage growth had accumulated The plants were separated into morphological parts before measuring their size and in vitro digestible dry matter (IVDDM) There were few plant density × orchardgrass clone interactions, and correlation coefficients of clones grown at the two plant densities generally were high (eg 0·87 in spring and 0·67 in summer for IVDDM of total herbage) Plant density had little effect on morphology of leaf blades from reproductive tillers, but leaf blades of vegetative tillers were 12% (spring) and 22% (summer) longer from sward than from spaced plantings Moreover, reproductive tillers were 26% taller in sward than in spaced plantings Also, leaf blades of vegetative tillers in spring growth were more than twice as long, of similar width and 65% thicker than leaf blades from reproductive tillers Because divergent genotypes respond similarly to plant density, it is concluded that observations taken in spaced plantings of orchardgrass can be used to make inferences about relative differences in sward plantings for the traits studied
7 citations
01 Jan 1993
TL;DR: This book discusses early Silurian and Late Ordovician Environments, the Origin of Plant Signal Transduction Systems, Phytohormones, Photomorphogenesis, and Secondary Metabolism, and the Evolution of Plant Sexual Reproduction.
Abstract: Early Silurian and Late Ordovician Environments. Approaches to an Understanding of Early Land Plant Evolution. The Charophycean Algae. Morphology, Ecology, and Physiology of Charophytes. Gaps Between Charophycean Algae and Land Plants. The Evolution of Plant Morphology: Cell Walls, Cytoskeleton, Cytokinesis, Intercellular Communication, and Histogenesis. Evolution of Plant Sexual Reproduction. The Origin of Plant Signal Transduction Systems, Phytohormones, Photomorphogenesis, and Secondary Metabolism. Land Plant Origins----A Summary. Literature Cited. Index.
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01 Jan 1993
TL;DR: Overall, white clover plants in Waikato dairy pastures are considerably larger than plants in Manawatu sheep pastures, and are vulnerable to mismanagement in dairypastures, just as has been demonstrated in pasture grazed by sheep.
Abstract: Seasonal changes in white clover plant morphology were investigated in Waikato dairy pasture. Plants were classified according to the degree of branching, 2nd-order plants comprising the bulk of the population (47%) throughout the year. There was a slightly greater proportion of lst-order plants than found in similar studies on sheep-grazed swards in Manawahr. Plant fragmentation occurred in late spring, increasing the proportion of lstorder plants. A corresponding decrease in plant size was observed, with minimum values measured for most characteristics, i.e., stolon, leaf and root dry weight (DW); stolon length, and number of leaves, roots and growing points. Overall, white clover plants in Waikato dairy pastures are considerably larger than plants in Manawatu sheep pastures. The trial highlighted that because white clover plants in spring are small, they are vulnerable to mismanagement in dairy pastures, just as has been demonstrated in pasture grazed by sheep. There were, however, some significant differences in white clover plant structure in dairy pastures compared with sheep-grazed swards.