scholarly journals Studia nad kariologią i rozwojem pyłku kilku odmian Medicago saliva L. Cz. I [Studies on karyology and pollen development in several varieties of Medicago sativa L. Part I]

2015 ◽  
Vol 24 (2) ◽  
pp. 319-341
Author(s):  
K. Bijok ◽  
E. Adamkiewicz ◽  
L. Grygorczyk
Keyword(s):  
Medicago Sativa ◽  
Meiotic Division ◽  
Pollen Development ◽  
Pollen Grains ◽  
Mature Pollen ◽  
Meiotic Stage ◽  
Medicago Saliva ◽  
Medicago Sativa L

At the stage of diakinensis and metaphase of the first meiotic division, conjugating chromosomes in the form of bivalents were always observed. At the pre-meiotic stage some of .the mother pollen cells underwent degeneration (in 'Australian' var. 17% in 'Warminska' 20%, in 'Kleszczewska' 23%, in 'Grimma' 30% and in 'Miechowska' 40%). In the degenerating mother pollen cells no meiotic division were observed. In the surviving mother pollen cells, meiotic division were found to be normal. The mature pollen grains were trinucleate.

CYTOLOGY OF 2n POLLEN FORMATION IN DIPLOID ALFALFA, MEDICAGO SATIVA

1979 ◽  
Vol 21 (4) ◽  
pp. 525-530 ◽  
Author(s):  
Nicholi Vorsa ◽  
E. T. Bingham
Keyword(s):  
Medicago Sativa ◽  
Seed Set ◽  
Pollen Grains ◽  
Genetic Constitution ◽  
2N Pollen ◽  
Diploid Parent ◽  
2N Gamete ◽  
Medicago Sativa L ◽  
Pollen Formation ◽  
Mother Cells

Four diploid (2x) clones of alfalfa, Medicago sativa L., which produced good seed set when used as male parents in 4x-2x crosses were selected for study. The 2x clones descended from 2x haploids of cultivated 4x alfalfa. Fertility in the 4x-2x cross was due to the production of pollen with the unreduced chromosome number (2n pollen) from the 2x parent. The cytological mechanism of 2n pollen formation was found to be disorientation of spindles at metaphase II in up to 38% of the pollen mother cells. Thus, both n and 2n pollen were produced by all four diploids examined. Normal spindles at metaphase II were oriented such that they defined the poles of a tetrahedron and resulted in normal tetrads in a tetrahedral arrangement. Disoriented spindles were basically parallel to each other and resulted in formation of dyads and occasionally a triad. Dyads developed into two 2n pollen grains; triads developed into one 2n and two n pollen grains. Since both n and 2n pollen grains are produced by the diploids, they can be maintained as diploids or they can be used as male parents in crosses to tetraploids. The genetic constitution of 2n pollen resulting from parallel spindles is similar to that expected after first division restitution of meiosis and much of the heterozygosity of the diploid parent is conserved in the gametes. The 2n gamete mechanism has potential application in germplasm transfer and in maximizing heterozygosity in tetraploid hybrids.

scholarly journals A Cytological Study of Anther and Pollen Development in Chinquapin (Castanea henryi)

HortScience ◽  
2020 ◽  
Vol 55 (6) ◽  
pp. 945-950
Author(s):  
Weiping Zhong ◽  
Zhoujun Zhu ◽  
Fen Ouyang ◽  
Qi Qiu ◽  
Xiaoming Fan ◽  
...  
Keyword(s):  
Pollen Development ◽  
Lipid Droplets ◽  
Morphological Characteristics ◽  
Pollen Grains ◽  
Middle Layer ◽  
Anther Development ◽  
Mature Pollen ◽  
Anther Wall ◽  
Male Flowers ◽  
Microspore Stage

The normal development of anthers and the formation of functional pollen are the prerequisites for successful pollination and fertilization. In this study, we observed dynamic changes in inflorescence and anther development in the chinquapin (Castanea henryi) using stereomicroscopy, light microscopy, and transmission electron microscopy. We found that cytokinesis during meiosis in microsporocytes was of the simultaneous type, and that the tetrads were mainly tetrahedral. Mature pollen grains contained two cells with three germ pores. The anther wall was of the basic type and composed of epidermis, endothecium, middle layers, and tapetum. Mature anthers had no middle layer and tapetum. The tapetum was of the glandular type. At the early microspore stage, a large number of starch granules appeared in the endothecium, which was deformed at the late microspore stage. Lipid droplets appeared in tapetum during the early microspore stage, and a few lipid droplets were still found during tapetum degeneration. The mature pollen accumulated a large amount of starch and lipids. These findings demonstrated that the anther wall provides nutrients and protection for pollen development. There is relatively stable correspondence between the external morphological characteristics of male flowers and internal structure of anther development.

Développement de l'anthère et du grain de pollen chez une espèce sauvage apparentée à la canne à sucre (Saccharum spontaneum)

1996 ◽  
Vol 74 (5) ◽  
pp. 788-795 ◽  
Author(s):  
D. Roques ◽  
P. Feldmann
Keyword(s):  
Pollen Development ◽  
Pollen Grains ◽  
Mature Pollen ◽  
Saccharum Spontaneum ◽  
Canne À Sucre ◽  
Secretory Type ◽  
Fertile Male ◽  
La Canne À Sucre

A study of the histocytological characteristics of anthers and pollen development of fertile male genotypes of Saccharum spontaneum L. support the division of microsporogenesis into nine distinct stages: premeiosis, meiosis and tetrad, young uninucleate microsporal stage, median uninucleate microsporal stage, median vacuolized uninucleate microsporal stage, late vacuolized uninucleate microsporal stage, first pollinic mitosis, second pollinic mitosis, mature pollen. Pollen grains are subspherical, monosporal, operculated with verrucose type ornamentations. A secretory type tapetum, present from the very first microsporal stages, is covered with orbicules persisting until anthesis. Keywords: Saccharum spontaneum, microsporogenesis, pollen, tapetum. [Journal translation]

scholarly journals Studia embriologiczne u pięciu odmian Medicago saliva L. Cz. II [Embriological studies in five varieties of Medicago sativa L. Part II.]

2015 ◽  
Vol 26 (1) ◽  
pp. 31-51
Author(s):  
K. Bijok ◽  
E. Adamkiewicz ◽  
L. Grygorczyk
Keyword(s):  
Medicago Sativa ◽  
Embryo Sac ◽  
Endosperm Development ◽  
Climatic Conditions ◽  
Low Fertility ◽  
Seed Setting ◽  
Medicago Saliva ◽  
Poor Seed ◽  
Medicago Sativa L ◽  
Pollination And Fertilization

The objective of this study was to elucidate the problem of low seedy yields of five varieties of <i>Medicago sativa</i> L. (Australijska, Grimma, Kleszczewska, Miechowska, and Warmińska) under climatic conditions of northern Poland. The study included pollination and fertilization processes, embryo sac, embryo and endosperm development. These factors in case of lack of the proper amount of pollen, and insufficient number of pollinators, may under certain environmental conditions results in poor seed setting and low fertility of the varieties studied.

scholarly journals INSECT PESTS AND THE EVOLUTION OF DEFENSIVE GLANDULAR TRICHOMES IN ALFALFA

1985 ◽  
Vol 65 (3) ◽  
pp. 589-596 ◽  
Author(s):  
ERNEST SMALL
Keyword(s):  
Medicago Sativa ◽  
Key Words ◽  
Geographical Distribution ◽  
Insect Pests ◽  
Glandular Trichomes ◽  
The Caucasus ◽  
Medicago Saliva ◽  
Medicago Sativa L ◽  
High Concentrations ◽  
Medicago Species

Glandular trichomes can defend (Medicago species from herbivores in a variety of insect orders. Wild alfalfas with high concentrations of glandular trichomes occur in a restricted portion of the geographical range of the species (Medicago saliva L. sensu lato), especially in the Caucasus, Ukraine, and adjacent areas of the USSR. These observations suggest that this adaptation was developed to defend the alfalfa against insect pests with similar geographical distribution. That M. sativa plants with pods covered with glandular hairs tend to have larger, if fewer, seeds than plants with pods lacking the hairs also suggests an adaptation against herbivores. Because the glandular trichomes occur primarily on the ovaries and pods, the pests likely feed on seeds. After considering the biology and geography of the major Soviet insect pests of cultivated alfalfa, it was concluded that the most likely insects responsible for the localized evolution of pod glandularity are species of Tychius (Coleoptera: Curculionidae).Key words: Alfalfa, Medicago sativa L., seed chalcid, Brachophagus, Tychius, glandular trichomes, pest resistance (immunity)

Pollen development in Douglas fir (Pseudotsuga menziesii)

1971 ◽  
Vol 49 (8) ◽  
pp. 1263-1266 ◽  
Author(s):  
John N. Owens ◽  
Marje Molder
Keyword(s):  
Pseudotsuga Menziesii ◽  
Pollen Development ◽  
Pollen Grains ◽  
Spore Wall ◽  
Douglas Fir ◽  
Mature Pollen ◽  
Stalk Cell ◽  
Wall Structure ◽  
Normal Sequence ◽  
Tube Cell

The normal sequence of pollen development in Douglas fir is described and is essentially the same as that for Pinus. Mature pollen grains normally consist of five cells: two lens-shaped prothallial cells, a stalk cell, a body cell, and a large tube cell. The normal sequence of development is described as well as the structure and histochemistry of the spore wall. Possible reasons are given for earlier misinterpretations of pollen development and spore wall structure in Douglas fir.

Resolution of Channels in the Exine by Translocation of Colloidal Iron

1971 ◽  
Vol 29 ◽  
pp. 352-353
Author(s):  
John R. Rowley
Keyword(s):  
Phosphate Buffer ◽  
Pollen Development ◽  
Osmium Tetroxide ◽  
Pollen Grains ◽  
Deionized Water ◽  
Colloidal Iron ◽  
Fixed Material ◽  
Epilobium Angustifolium ◽  
Untreated Material ◽  
Microspore Mitosis

The morphology of the exine of many pollen grains, at the time of flowering, is such that one can suppose that transport of substances through the exine occurred during pollen development. Holes or channels, microscopic to submicroscopic, are described for a large number of grains. An inner part of the exine of Epilobium angustifolium L. and E. montanum L., which may be referred to as the endexine, has irregularly shaped channels early in pollen development although by microspore mitosis there is no indication of such channeling in chemically fixed material. The nucleus in microspores used in the experiment reported here was in prophase of microspore mitosis and the endexine, while lamellated in untreated grains, did not contain irregularly shaped channels. Untreated material from the same part of the inflorescence as iron treated stamens was examined following fixation with 0.1M glutaraldehyde in cacodylate-HCl buffer at pH 6.9 (315 milliosmoles) for 24 hrs, 4% formaldehyde in phosphate buffer at pH 7.2 (1,300 milliosmoles) for 12 hrs, 1% glutaraldehyde mixed with 0.1% osmium tetroxide for 20 min, osmium tetroxide in deionized water for 2 hrs and 1% glutaraldehyde mixed with 4% formaldehyde in 0.1M cacodylate-HCl buffer at pH 6.9 for two hrs.

Estimación de biomasa aérea de forrajes de invierno bajo riego a través de un dron

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Francisco Gavi Reyes ◽  
César Botello-Aguillón ◽  
Leonardo Tijerina-Chávez ◽  
Arturo Galvis-Spíndola ◽  
Rodrigo Roblero-Hidalgo
Keyword(s):  
Medicago Sativa ◽  
Avena Sativa ◽  
Medicago Sativa L

E Objetivo: Desarrollar un procedimiento para estimar biomasa con imágenes digitales captadas desde un dron y modelación 3D (ID-Dron-3D) aplicable en alfalfa (Medicago sativa L.) y avena forrajera (Avena sativa L.). Diseño/metodología/aproximación: Con una cámara digital acoplada al dron se obtuvieron imágenes antes de la cosecha de los cultivos, que fueron procesadas con software para luego estimar volumen de biomasa. En cada cultivo se midió altura de la planta y área cosechada, volumen aparente y real de biomasa, y peso de biomasa fresca y seca. Resultados: Con base en el análisis de regresión se obtuvieron modelos lineales a una p<0.05 para predecir: biomasa fresca en avena (R2=0.70) y alfalfa (R2 =0.47); y biomasa seca en avena (R2=0.78) y en alfalfa (R2=0.31) mediante ID-Dron-3D. Limitaciones del estudio/implicaciones: Considerando las R2 de los modelos obtenidos, los resultados en la avena forrajera fueron mejores, respecto a los detectados en alfalfa, lo cual se puede deber a la mayor variabilidad de la cobertura vegetal, ya que, en algunas unidades de muestreo, las plantas de alfalfa no cubrían completamente el suelo. Hallazgos/conclusiones: El rendimiento de biomasa fresca y seca de ambos cultivos se correlacionó significativamente con su respectivo volumen aparente estimado con imágenes digitales tomadas desde un dron y su procesamiento 3D (ID-Dron-3D).

ALFALFA (Medicago sativa L.) CULTIVADA EN CAMPECHE, MÉXICO Y SU INTEGRACIÓN LOCAL EN LA ALIMENTACIÓN DE CORDEROS EN CONFINAMIENTO

2018 ◽  
Vol 11 (9) ◽  
Author(s):  
CC. Castillo-Águilar
Keyword(s):  
Medicago Sativa ◽  
Pennisetum Purpureum ◽  
Medicago Sativa L

Se comparó el uso de diferentes dietas con base en heno de alfalfa cultivada (Medicago sativa L.) en Campeche y su relación con un concentrado comercial y pasto Taiwán (Pennisetum purpureum), T1=concentrado comercial, T2=T1+heno de alfalfa, T3=T1+pasto Taiwán, T4=heno de alfalfa. Se evaluó el comportamiento productivo y metabólico de corderos en sistema intensivo utilizando 20 corderos machos con encaste de Pelibuey, Dorper y Black Belly de 12.5±1 kg de peso vivo (PV). Se midió el consumo de materia seca total (CMS), la ganancia diaria de peso (GDP), la conversión alimenticia (CA), y la digestibilidad in situ de la materia seca (DISMS). También fueron evaluados el pH, nitrógeno amoniacal (NH3) y la concentración de ácidos grasos volátiles (AGV) en líquido ruminal. La mejor GDP en gramos por día, de 234 g (p?0.05) se obtuvo en el T2; en contraste, el T3 mostró la menor GDP. La dieta que incluyó la mezcla de heno de alfalfa y concentrado mejoró significativamente las condiciones de las variables pH, NH3 y AGV (p?0.05).

ALFALFA VARIETIES ZONED IN THE CENTRAL CHERNOZEM ZONE OF THE RUSSIAN FEDERATION

2020 ◽  
Author(s):  
Galina Stepanova
Keyword(s):  
Medicago Sativa ◽  
Dry Matter ◽  
Maximum Yield ◽  
The State ◽  
Average Yield ◽  
State Register ◽  
Independent Evaluation ◽  
Medicago Sativa L ◽  
Alfalfa Varieties ◽  
Central Chernozem

The article describes the main morphological and biological features of alfalfa varieties included in the State register of breeding achievements approved for use in the Central Chernozem zone of Russia. A total of 32 alfalfa varieties are included in the State register. This is 9 varieties of blue alfalfa (Medicago sativa L. subsp. Sativa) of domestic selection and 8 foreign, 11 varieties of variable alfalfa (Medicago sativa L. nothosubsp. varia (Martyn) Arcang.) domestic selection and 1 variety of foreign and 3 varieties of yellow alfalfa (Medicago sativa L. subsp. falcata (L.) Arcang.). It shows the average and maximum yield of varieties determined in the process of state variety testing, as well as independent evaluation in research institutions in the region. Varieties of blue alfalfa of domestic selection Kevsala, Elena, Satellite, Vavilovskaya Yubileynaya were the most productive. The average yield of dry matter of these varieties reaches 8.4–9.2 t/ha, the maximum — 15.3–17.7 t/ha. Alfalfa varieties Timbale and Galaxy were the most productive among foreign varieties: the average yield of dry matter was 8.1 and 8.3 t/ha, the maximum – 15.5 and 17.2 t/ha. Varieties of alfalfa variable Vitalina and Vela provided an average yield of dry matter of 7.6 and 9.0 t/ha, the maximum yield reached 15.4 and 18.1 t/ha.

Sign in / Sign up

Export Citation Format

Share Document