The Cytological Basis For Homothallism And Heterothallism In The Agaricaceae

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141249/1/ajb209513.pd

Flower Bud Development in Some Varieties of Tulip

A study is being made of the time of initiation and development of the flower bud in three classes of tulips. All floral organs are present in November. The flower bud is twice as large in the earliest (Mendel) class than in the latest (Darwin) class, but the cytological condition in the anthers and ovules is strikingly similar; pollen is in the late quartet to early microspore stage, ovules are very small primordia with no evidence of integuments or megaporocyte. Expansion of flower bud size is in proportion to earliness, pollen development is virtually parallel, and megagamentophyte development is slightly more rapid in the earliest class

Cytoplasmic Structures in the Basidium Revealed by Silver Impregnation

Basidia of Coprinus fimetarius treated by silver impregnation methods exhibit blackened bodies in the cytoplasm. The size, shape, position and distribution of these bodies correspond to those of bodies demonstrated by mitochondrial techniques. The silver-absorbing bodies in the basidium are unlike the Golgi bodies demonstrated in some animal cells by silver impregnation, but bear much resemblance to mitochondria

Further Studies of Non-Nuclear Structures in the Basidium

Pursuing a further analysis of the so-called Golgi apparatus in the basidium, tests were made with some accepted chondriosome techniques. Typical chondriosomes were found to be present, quite unlike the bodies associated with the Golgi apparatus. It is suggested that the Nebenkern and Golgi material are discrete cell bodies, apart from nucleus, chondriosomes and centrosomal mechamsm

Some Cytological Details of Ceresan Poisoning in Seedlings

Heavy overdoses of Ceresan induces the formation of giant cells in seedlings of corn and small grains. Cell division is inhibited. Nuclear division occurs, with more or less normal prophases. Anaphase separation of halves of split chromosomes fails to take place, accompanied by apparent failure of the sprindle mechanism. Cell wall formation may he initiated, but the evidence suggests subsequent dissolution of partial cell walls

Pathological Polyploidy in Seedlings of Corn and Sorghum

The writer had demonstrated that Coprinus sterquilinus contains an extra-nuclear mechanism which bears structural homologies with the Golgi apparatus in animal spermatocytes. Numerous other Hymenomycetes have been examined. Coprinus atramentarius contains a distinct Nebenkern sphere, consisting of a large hyaline sphere, in which there are peripheral, chromophilic granules. This body is most distinct just before the meiotic division of the fusion nucleus occurs. It is probable that the sterigmatic bodies described by various workers, are derived from this Golgi apparatus, rather than from the centrosomes

The Presence of a Nebenkern In Coprinus atramentarius

The writer had demonstrated that Coprinus sterquilinus contains an extra-nuclear mechanism which bears structural homologies with the Golgi apparatus in animal spermatocytes. Numerous other Hymenomycetes have been examined. Coprinus atramentarius contains a distinct Nebenkern sphere, consisting of a large hyaline sphere, in which there are peripheral, chromophilic granules. This body is most distinct just before the meiotic division of the fusion nucleus occurs. It is probable that the sterigmatic bodies described by various workers, are derived from this Golgi apparatus, rather than from the centrosomes

Some Meiotic Irregularities in Cultivated Lilies

Refinements of the paraffin technique make it possible to demonstrate critical details of meiosis. The process yields figures that are comparable to the results of the smear process. Progressive synapsis during amphitene, and the tetrad structure of the chromosome at strepsiphase can be readily demonstrated

The Nuclear Cycle and Sexuality of Trametes peckii

Trametes peckii is a heterothallic member of the Polyporaceae. The sex classes exhibit considerable irregularity, making any attempt to classify this organism as bipolar or tetrapolar highly questionable. Segregation of monosporous haplonts into cottony and non-cottony mycelia is clearly indicated. The dikaryotic secondary mycelium is always cottony, suggesting the possibility of the dominance of the cotton character. Repulsion between certain combinations of two mycelia of opposite sex groups, and the absence of repulsion between other pairs, resembles the phenomenon designated as Barrage by Vandendries. This fungus appears to exhibit three segregating characters; sex potentiality, haploid mycelial character, and repulsion

Development of Axillary Buds of the Tillers of Zea

An inbred line of popcorn and a line that contained teosinte germ plasm were compared with respect to the inflorescences of the numerous tillers produced by plants of these lines. In both lines, all terminal and axillary apices of the tillers initiated inflorescences. No axillary tassels were found on the tillers of either line. On a popcorn tiller, a terminal inflorescence was either a tassel, a tassel that bore a few scattered kernels, an ear, or an ear that had basal tassel branches. Every tiller of the teosinte-contaminated corn had a terminal tassel