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[Characterization and behaviour in nursery of three Eucalyptus globulus Labill ssp. globulus provenances harvested in Chile]
1992
Urrutia T, Ruben
Three Eucalyptus globulus Labill. ssp. globulus provenances were harvested in Chile and the collected seed separated by size in three groups for each provenance. The physiological characteristics and physical attributes as well as the size groups participation on the total weight were determined. The effect of provenance on seed germination was established in laboratory and results on emergence, growth and morphological variables of seedlings were obtained in the nursery using a randomized block design. Provenances affected significant germination and emergence of seedlings but there was no effect on height or morphological characteristics of seedlings
Show more [+] Less [-]Caracterizacion y comportamiento en vivero de tres procedencias de semillas de Eucalyptus globulus Labill ssp. globulus cosechadas en Chile.
1992
Urrutia T Ruben
Three Eucalyptus globulus Labill. ssp. globulus provenances were harvested in Chile and the collected seed separated by size in three groups for each provenance. The physiological characteristics and physical attributes as well as the size groups participation on the total weight were determined. The effect of provenance on seed germination was established in laboratory and results on emergence, growth and morphological variables of seedlings were obtained in the nursery using a randomized block design. Provenances affected significant germination and emergence of seedlings but there was no effect on height or morphological characteristics of seedlings.
Show more [+] Less [-]Seedling recruitment limitation in white clover (Trifolium repens; Leguminosae).
1992
Barrett J.P. | Silander J.A. Jr.
White clover (Trifolium repens L.) is a stoloniferous clonal legume. Dynamics of white clover populations are controlled by the recruitment of both seedlings (genets) and node production (ramets). To understand the role of seedling dynamics in natural populations of white clover, the recruitment and mortality of seedlings in a lawn and pasture clover population were followed and the roles of biotic and abiotic factors in seedling recruitment and survival were assessed. Seedling recruitment was several orders of magnitude less than vegetative recruitment in both lawn and pasture populations. However, at least several new genets are added to these populations on a yearly basis. In both locations, physical disturbances may open sites for seed germination, as disturbed sites had higher seed germination rates than undisturbed sites. However, these sites were not favorable for long-term establishment due to such factors as frost upheaval. Therefore, there are trade-offs in safe site attributes for seed germination and establishment that strongly limit recruitment in natural populations of white clover.
Show more [+] Less [-]Seedling recruitment limitation in white clover (Trifolium repens; Leguminosae)
1992
Barrett, J.P. | Silander, J.A. Jr
White clover (Trifolium repens L.) is a stoloniferous clonal legume. Dynamics of white clover populations are controlled by the recruitment of both seedlings (genets) and node production (ramets). To understand the role of seedling dynamics in natural populations of white clover, the recruitment and mortality of seedlings in a lawn and pasture clover population were followed and the roles of biotic and abiotic factors in seedling recruitment and survival were assessed. Seedling recruitment was several orders of magnitude less than vegetative recruitment in both lawn and pasture populations. However, at least several new genets are added to these populations on a yearly basis. In both locations, physical disturbances may open sites for seed germination, as disturbed sites had higher seed germination rates than undisturbed sites. However, these sites were not favorable for long-term establishment due to such factors as frost upheaval. Therefore, there are trade-offs in safe site attributes for seed germination and establishment that strongly limit recruitment in natural populations of white clover.
Show more [+] Less [-]Relationship of grain length, width and weight to seedling vigor in rice (Oryza sativa L.)
1992
Teng, S. | Vergara, B.S. | Alejar, A.A. (International Rice Research Inst., Los Banos, Laguna (Philippines))
Seedling vigor is an important agronomic trait for crop establishment. The relationship of seed physical traits other than seed weight to seedling vigor in rice is well-known. An experiment was set up to study the above relationship. The seedling-growth of 38 rice varieties with different grain length, width, and weight was measured to determine the relative contribution of these grain physical characteristics to seedling vigor. Grain weight, whether heavy, medium, or light, was positively correlated with seedling leaf area and dry weight, but negatively correlated with germination percentage. This relationship was clearly demonstrated among cultivars (intervarietal) rather than within a single cultivar (intravarietal). The longer, wider, and heavier grains of a given rice cultivar produced taller seedlings that are characterized by larger leaf area and greater dry matter production. The study confirmed that grain weight is the best selection factor to use for producing vigorous seedlings whether within or between cultivars. Grain length and width, to a certain extent, can be used as selection criteria for seedling vigor in different rice varieties as measured by seedling leaf area and germination percentage, respectively
Show more [+] Less [-]Position of the vegetative and sperm cells of germinating pollen grain in maize (Zea mays L.)
1992
Chang, M.T. | Neuffer, M.G.
Position of the vegetative and sperm cells of germinating pollen grain in maize (Zea mays L.)
1992
Chang, M.T. | Neuffer, M.G.
Maize pollen grains germinating on either defined media or fresh silks are described. The vegetative cell and sperm cells were distinguished clearly by size, shape and staining intensity. The positions of the sperm cells and that of the vegetative cell (tube nucleus), with respect to the pollen grain and the elongated pollen tube, were measured and expressed as its distance from the germ pore of the pollen grain. The relative position with respect to each other was also determined. Our results provide support that: 1) the position of sperm cells during early pollen germination is significantly variable; 2) the occurrence of sperm cells at several specific positions in the germinating pollen grain varies considerably between the inbred, B73, and the hybrid, Pearl and Honey; 3) there is good agreement in the behavior of in vivo and in vitro materials; 4) there is no physical association among the vegetative cell and the sperm cells during early maize pollen germination; 5) the size and shape of sperm cells inside the pollen tube vary; 6) there is no physical evidence to prove that the movement of sperm cells in the pollen tube is cell directed; and 7) the vegetative cell is the last of the three units to move into the pollen tubes from the pollen grain.
Show more [+] Less [-]Position of the vegetative and sperm cells of germinating pollen grain in maize (Zea mays L.)
1992
Chang, M.T. (Imperial Chemical Industries (ICI), Slater (USA)) | Neuffer, M.G. (Missouri Univ., Columbia (USA). Dept. of Agronomy)
Maize pollen grains germinating on either defined media or fresh silks are described. The vegetative cell and sperm cells were distinguished clearly by size, shape and staining intensity. The position of the sperm cells and that of vegetative cell (tube nucleus), with respect to the pollen grain and the elongated pollen tube, were measured and expressed as its distance from the germ pore of the pollen grain. The relative position with respect to each other was also determined. Our results provide support that: 1) the position of sperm cells during early pollen germination is significantly variable; 2) the occurrence of sperm cells at several specific positions in the germinating pollen grain varies considerably between the inbred, B73, and the hybrid, Pearl and Honey; 3) there is good agreement in the behaviour of in vivo and in vitro materials; 4) there is no physical association among the vegetative cell and sperm cells during early maize pollen germination; 5) the size and shape of sperm cells inside the pollen tube vary; 6)there is no physical evidence to prove that the movement of sperm cells in the pollen tube is cell directed; and 7) the vegetative cell is the last of the three units to move into pollen tube from the pollen grain | [Vengono descritti granuli di polline posti a germinare o su substrati definiti o su stili. La cellula vegetativa e le cellule generative sono state chiaramente distinte per le dimensioni, la forma e l'intensita' della colorazione. Le posizioni delle cellule generative e quella della cellula vegetativa, con riguardo al granulo di polline e al tubetto pollinico allungato, sono state misurate ed espresse come la distanza dal poro germinale del grano di polline. E' stata anche determinata la posizione relativa di entrambi. I nostri risultati hanno fornito queste informazioni: 1. la posizione delle cellule generative all'inizio della germinazione pollinica e' notevolmente variabile; 2. le diverse posizioni specifiche delle cellule generative nel polline germinante variano notevolmente tra l'inincrocio, B37, e l'ibrido, Pearl e Honey; 3. c'e' un buon accordo nel comportamento in vivo e in vitro; 4. non c'e' associazione fisica tra la cellula vegetativa e le cellule generative all'inizio della germinazione del polline del mais; 5. la dimensione e la forma delle cellule generative nel tubetto pollinico varia; 6. non vi e' prova fisica che testimoni che il movimento delle cellule generative nel tubetto pollinico sia diretto dalla cellula; 7. la cellula vegetativa e' l'ultima delle tre unita' a muoversi nel tubetto pollinico dal granulo di polline]
Show more [+] Less [-]Localidades y grados de madurez en la calidad de semilla de chile morrón (capsicum annuum l.). Full text
1992
Martínez De La cerda, Jesús | García, Leticia Angélica | Gómez Contreras, Héctor | Montes Cavazos, Fermín
"El presente trabajo se realizó con el objetivo de determinar el rendimiento y calidad de semilla de chile morrón en dos localidades y cosechando los frutos en diferentes grados de madurez. De acuerdo a los resultados, la mejor localidad fue Landeros, Coah. donde se obtuvo mejor calidad física y fisiológica de la semilla. El mejor grado de madurez para calidad física y capacidad de germinación fue en rojo; siendo en verde donde se obtuvo semilla con un nivel de vigor más alto, medido como germinación después de estos y emergencia en almácigo. La mejor interacción se obtuvo en Landeros, Coah. cosechando en verde y almacenando los frutos por 7 días a una temperatura de 240 C, siendo el único tratamiento donde se obtuvo semilla con calidad para siembras comerciales." | "A study was carried out in arder to determine the effect of two environments and three fruit maturity stages on seed yield and quality of bell peppers (Capslcum annuum L.). According to the results the best environment was the locality of Landeros, Coah. where the physical and physiological quality of the seeds were higher. The optimum fruit stage for physical quality and germination capacity was harvesting at phyisiological maturity (red); while in comercial maturity (green) the seed had the highest level of vigor as indicated by the results of the vigor tests (germination after acelerated aging and emergence). The best interaction was the locality of Landeros, Coah., harvesting in comercial maturity (green) and storing the fruits for a period of 7 days at a room temperature of 24° C, being the only treatment with seed quality for comercial seeding."
Show more [+] Less [-]Effect of mixing during the drying period on soybean seed quality
1992
Sumardi (Balai Penelitian Tanaman Pangan, Bogor (Indonesia). Kelompok Peneliti Fisiologi)
An experiment to study the effect of drying on soybean seed quality was undertaken at Bogor Research Institute for Food Crop in 1988. Two soybean varieties (Wilis and Tidar) were used, different wet soybean sample were dried until a moisture content of 9 percent with 3 drying-mix periods, namely 4 hours, 2 hours, and 1 hour, respectively. The dry soybeans were threshed using two methods, using the mechanical power (digebuk) and the physical power (rontok sendiri). The best result was obtained when soybean straw was dried-mix at a period of hourly. The drying time was shorter, it was 28 hours or 4 day with moisture content decreasing capacity of 4,1 percent daily or 0,5 hourly for Wilis and 4.25 percent daily or 0,61 percent hourly for Tidar. The best seed germination percentage was obtained on Wilis 98,33 percent with 97,67 percent vigor, followed by Tidar (95,67 percent) with 95,10 percent vigor.
Show more [+] Less [-]Effect of physical properties of surface soil on seedling emergence
1992
Yamada, N. (Kagawa Univ., Miki (Japan). Faculty of Agriculture)
Effect of some physical properties of soil on seedling emergence of some kinds of crops were investigated both under laboratory and field conditions. In laboratory test, under the constant condition of temperature and moisture of soil, germination and emergence of soybean, rice and wheat were experimented using four kinds of soils differing in their compacted stress, respectively. In a field of sandy soil, emergence tests naked barley, soybean and sweet corn were carried out each two times from 1982 to 1987. As a result of these emergence tests, though there are a little differences among the kinds of crops, it is proved that the gas phase of soil influences most significantly on seedling emergence, and especially in field, three phase including gas phase influence on it. Furthermore, as an experimental result on relation between three phases and air permeability of soil, air permeability under 10 -4 cm/s proves to prevent seedling emergence remarkably. Therefore, under profitable conditions of temperature and moisture, keeping air permeability of soil over 10 -4 cm/s seems necessary for satisfactory seedling emergence
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