ABSTRACT
Different effects of fasciation on the structure of blastozones and ultimately on the morphology of the plants of the two families investigated was detected. The results of this study demonstrate that in Arabidopsis thaliana phyllotaxis changes, leading to the formation of whorled leaf aestivation (two or four leaf in the whorl). We also demonstrated that in Pisum sativum the number of folioles of a compound leaf increased, the number of stipules also increased, and stipules can grow together and form a structure similar to the sheath of Gramineae. Our results demonstrated that a common manifestation of fasciations in Arabidopsis and Pisum is the formation of a flattened meristem, which extended along the same line (axes of fasciation).
Subject(s)
Arabidopsis/growth & development , Meristem/growth & development , Pisum sativum/growth & development , Plant Leaves/growth & development , Meristem/ultrastructure , Plant Leaves/ultrastructureABSTRACT
Leaf anatomy was studied in the mosaic Ficus benjamina cv. Starlight and non-chimeric Ficus benjamina cv. Daniel. The number of chloroplasts in a white, chlorophyll-deficient tissue declines as compared to the green tissue. However, their functional activity is retained. The leaf of the mosaic F. benjamina contains two or, sometimes, three subepidermal layers. Mesophyll forms one layer in the green and white parts of leaf palisade and one white and one green layer in the transitional zone (edge). In the transitional zone, green spongy mesophyll is located between two white spongy layers and the proportion of photosynthesizing cells varies. In cv. Daniel, there are two subepidermal layers and one layer of columnar mesophyll cells. According to the morphometry data, the proportion of white zone in the leaf correlates with the leaf position in the whole shoot: the higher the branch order, the larger the proportion of white zone. The total leaf area depends also on its position in the shoot. No such correlation was found in non-chimeric F. benjamina cv. Daniel. In the mosaic chimera, the source-sink status appears to depend on the leaf position in the shoot. Experiments with individual shoots of the same order and elimination of all lateral shoots have shown that the proportion of white zone in new leaves on the shoot increases with the total area of green zone. Thus, the area of assimilating shoot surface affects the formation of leaves in the meristem. A hypothesis was put forward that the source-sink state affects the ratio of green and white parts in the leaf primordium. Products of photosynthesis (carbohydrates) are a possible metabolic signal affecting the meristem. It cannot be excluded as well that the hormonal state undergoes changes in the chimeric plant.
Subject(s)
Chimera/anatomy & histology , Ficus/anatomy & histology , Photosynthesis , Plant Leaves/anatomy & histology , Ficus/cytology , Meristem/anatomy & histology , Meristem/cytology , Plant Leaves/cytology , Plant Shoots/anatomy & histology , Plant Shoots/cytologyABSTRACT
The mathematical model imitating floral organ spatial pattern formation (positioning) was developed. Computer experiments performed on its basis demonstrated that organ spatial pattern formation in typical crucifer flower occurred in successive order: medial sepals, carpels, lateral sepals, long stamens, petals and short stamens. The positioning was advanced in two directions, acropetally in the perianth and basipetally in the stamens and carpels. The organ type specifying and positioning take place non-simultaneously in different floral areas. The organ type specifying passed ahead of organ primordial spatial pattern formation. The modeling of flower development of several mutants demonstrated that arabidopsis genes AP2 and AG in addition to specifying floral organ types also determine the particular zones in the floral meristem for futur organ development. The AG gene controls the formation of basipetal patterning zones where the reproductive organs develop, AP2 maintains the proliferative activity in the floral meristem that form acropetal patterning zones where perianth organ develop.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/embryology , Computer Simulation , Flowers/embryology , Gene Expression Regulation, Developmental/physiology , Homeodomain Proteins/metabolism , Models, Statistical , Nuclear Proteins/metabolism , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Flowers/genetics , Homeodomain Proteins/genetics , Nuclear Proteins/geneticsABSTRACT
Studies of efflorescences of the mutants bractea and terminal flower1 and double mutant bra tfl1 of Arabidoipsis thaliana (L.) Heynh. have shown that the presence of a developed leaf in the node preceding the terminal flower is a necessary condition for the formation of the terminal flower perianth. This means that perianth cannot develop in an abracteose efflorescence of terminal flower. The second necessary condition for the terminal flower formation is a sufficient level of expression of the genes responsible for floral morphogenesis. Combination of these two conditions suffices for the development of a terminal flower with perianth. Since the general principles of organization are close for most flower plants, it can be stated that if the abracteose efflorescence is terminated by a flower with perianth, this is a consequence of forcing the lateral flower into the terminal position.
Subject(s)
Arabidopsis/physiology , Flowers/physiology , Arabidopsis/anatomy & histology , Arabidopsis/genetics , Flowers/anatomy & histology , Flowers/genetics , Gene Expression Regulation, Plant , Morphogenesis , Mutation , Plant Leaves/anatomy & histology , Plant Leaves/genetics , Plant Leaves/physiologyABSTRACT
Morphological analysis of flowers was carried out in Arabidopsis thaliana wild type plants and agamous and apetala2 mutants. No direct substitution of organs takes place in the mutants, since the number and position of organs in them do not correspond to the structure of wild type flower. In order to explain these data, a notion of spatial pattern formation in the meristem was introduced, which preceded the processes of appearance of organ primordia and formation of organs. Zones of acropetal and basipetal spatial pattern formation in the flower of wild type plants were postulated. It was shown that the acropetal spatial pattern formation alone took place in agamous mutants and basipetal spatial pattern formation alone, in apetala2 mutants. Different variants of flower structure are interpreted as a result of changes in the volume of meristem (space) and order of spatial pattern formation (time).
Subject(s)
Arabidopsis/anatomy & histology , Arabidopsis/genetics , Flowers/anatomy & histology , Flowers/genetics , Homeodomain Proteins/genetics , Nuclear Proteins/genetics , Plant Proteins/genetics , AGAMOUS Protein, Arabidopsis/genetics , Alleles , Arabidopsis Proteins , Mutation/genetics , Polymorphism, GeneticABSTRACT
Shoot system of a plant can be divided into elementary molecules composed of phyllome, internode, and meristem of the lateral bud. The capacity of plants for open growth is manifested as multiple reproductions of the modules. These main principles of plant structural organization can be used to formalize and integrate the data from various disciplines studying the shoot development--genetics of development, morphology, etc. At the example of model species Arabidopsis thaliana we show that the data on genetic control of shoot development can be considered in terms of individual modules reorganization. Several variants of the modules structural reorganization are allowed: reduction or transformation of phyllome, change in the internode length, and triggering active/inactive status of the lateral shoot meristem. Each variant of the module structure corresponds to specific pattern of genes activity. Such integration of the data on genetic and structural aspects of morphogenesis can form a basis for mathematical modeling of plant development.
Subject(s)
Botany/methods , Models, Biological , Plant Development , Plant Shoots/growth & development , Arabidopsis/genetics , Arabidopsis/growth & development , Flowering Tops/genetics , Flowering Tops/growth & development , Gene Expression Regulation, Plant , Models, Genetic , Plant Shoots/genetics , Plants/classificationABSTRACT
We have examined sympodial and monopodial models of bulb branching in Galanthus. The issue of the position of the reduced prophyll is discussed. We proposed a method of formal interpretation: parts of the plant were positioned on diagrams; several variants of axial schemes were matched to each diagram; the schemes were divided into two classes, monopodial and sympodial ones, and stability of each class was estimated. In order to decide about the model of Galanthus bulb branching, we have examined plants with additional inflorescences and plants with additional leaf series. We have shown that the sympodial model predicts the presence of the reduced prophyll at the base of the innovation bud in all studied cases. Consecutive stages of prophyll reduction (prophyll of the innovation bud) can be followed in Amaryllidaceae in the following sequence: Zephyranthes, a well-developed large prophyll with green lamina; Vallota, a developed prophyll with reduced green lamina; Haemanthus, a thin chaffy short-living prophyll. At the end of this sequence is Galanthus with completely reduced prophyll at the innovation bud.
Subject(s)
Liliaceae/growth & development , Models, Biological , Plant Shoots/growth & developmentSubject(s)
Fallopian Tubes/surgery , Pregnancy, Tubal/surgery , Female , Humans , Pregnancy , Vacuum CurettageSubject(s)
Cesarean Section/methods , Fetal Death/prevention & control , Infant Mortality , Female , Humans , Infant, Newborn , PregnancyABSTRACT
Forty patients with tumors of the esophagus, cardia and rectum, subjected preoperatively to gamma-therapy (500 rad for 6 days) and 24 patients subjected only to the operation (the control group) were examined for the heart rate, arterial pressure, minute and stroke heart volumes and circulatory volume (AFS--J131) before and after irradiation and 1, 3, 5 days following the operation. Gamma-therapy was found to result in more poor hemodynamic indices whether the heart is irradiated or not. In irradiation of the heart region (cancer of the esophagus and cardia) much poorer hemodynamic indices were noted.
Subject(s)
Cardiovascular System/radiation effects , Gastrointestinal Neoplasms/radiotherapy , Preoperative Care , Cardia , Esophageal Neoplasms/radiotherapy , Gamma Rays/therapeutic use , Hemodynamics/radiation effects , Humans , Rectal Neoplasms/radiotherapy , Stomach Neoplasms/radiotherapyABSTRACT
It is found that in irradiated patients subjected to abdomino-perineal extirpation of the rectum, a decrease of arterial pressure, blood volume, minute heart volume is more pronounced than in control patients.