Hair-like Filaments Research Articles

Biological observations during rearing experiments with the garfish Belone belone

The garpike Belone belone enters the Wadden Sea in April, to spawn in May and June. The large eggs (3mm) bear numerous, long hair-like filaments. Embryonic and larval development were investigated during rearing experiments in 1970 and 1971. The development of the embryo is described, with special reference to the circulatory system and “Kupffer's vesicles”. The embryos display ventilation with pectoral fins and gill opercula when still in the egg. They hatch after 2 or 3 weeks at 20° and 16°C, respectively. Newly hatched larvae accept a wide variety of prey, including dry, aquarium fish food. Growth, feeding behaviour, swimming performance, and survival of the juveniles were investigated in the laboratory and in a small outdoor pond. Young garpikes (1 to 3 cm standard length) survive at temperatures ranging from 13° to 25°C, and salinities from 7 to 50%. They may reach 12 to 15 cm in their first summer. Their cruising speed is estimated to be 1 to 2 body lengths/sec. Garpikes disappear from The Wadden Sea in October, and probably migrate offshore. Observations on the behaviour of adults (40 to 70 cm total length) in a large indoor tank, indicate that they avoid high light intensities in winter. Adults display panic reactions when the water temperature drops below 6° to 7°C; this indicates that garpikes probably migrate in winter to greater depth (lower light intensity), to avoid water temperatures below 6°C and rough weather conditions in the upper water layers.

Fecal Filaments Produced by Fungus- Infesting Larvae of Platydema oregonense1,2

Polyporns (Cryptoporus) volvatus Peck is a basidiomycete, the sporophores of which are found on dead or dying coniferous trees. The globose sporophores (Overholts 1953) (Fig. 1, 2) are about 1.5-8.5 cm broad by 1.0-3.5 cm thick. The margin of the sporophore forms a volva (or veil) which encloses the entire pore surface. One or rarely 2 small ventral apertures are found in the volva. In the chamber between the volva and the pore surface are found many insects (Hubbard 1892). Larvae of the tenebrionid beetle Platydema oregonense LeConte are frequently found inside the sporophore and are invariably associated with a mass of hairlike filaments. Peck (1878), in his description of P. volvatus judged the filaments to be a product of the fungus which served to hold the spore masses together. However, Hubbard (1892) suggested that the filaments may be produced by the larvae, while Leech (1947) briefly and without further elaboration referred to filaments produced by Platydema larvae infesting an unidentified sporophore on birch. Alternatively, Hubbard (1892) suggested that they could be a separate fungus growing on the larval debris.

The exudation of ice from stems of plants

This paper deals with the formation of ice fringes upon the Dittany ( Cunila mariana). The data presented are based upon experiments and observations in the field and in the laboratory. It was observed that the ice fringes are formed when the temperature falls to freezing point (o° C., 32° F.); but they are not a function of the hoar-frost which may be present upon the ground. The ice fringes do not form upon the side of a splinter which contains the pith or upon the line of fracture, but upon the outer woody surface. The formation of the ice fringe, however, is not a function of the surface condition of the stem. The stem is frequently found to be cracked, but usually no ice protrudes from the rifts. The growth of the ice fringe ceases when the ground is frozen to a depth of 2 to 3 cm., and when the moisture in the stem is frozen. The size of the ice fringes and the height to which they extend above the ground depend upon the rate of evaporation from the stem and upon the amount of moisture in the ground. Over 5 grammes of ice may be formed upon a single plant during a single night. Photographs are given of ice fringes formed upon stems which had been kept in the laboratory several months. They show that the ice may be formed upon stems without the roots. Hence the ice is not formed as a result of hydrostatic pressure exerted by the roots, which are perennial. All the observations are in agreement in showing that the moisture arises in the stem as the result of capillary attraction. The height (1 to 5 cm.) to which the moisture can rise within the stem is governed partly by the rate of evaporation from the surface. Microphotographs of thin sections of plants are given, which show the structure of stems of plants which do not form ice fringes; also microphotographs of sections of stems of plants which form ice fringes. It is shown that those plants which form ice fringes the most readily and in the greatest abundance have the most sap-tubes. The ice fringe is a composite of a number of very thin ribbons. In the laboratory the formation of the ice fringe was observed from its very beginning. The first stage in the production of the ice fringe consists of a single row of fine, hair-like filaments of ice. This row of ice filaments lengthens, up and down the stem. The filaments increase in number, thus forming a solid wedge-shaped tooth of ice, which constitutes the second stage of development. In the third stage of development the wedge-shaped tooth of ice widens and increases in length, as the result of freezing of the water which continues to soak out of the stem. There appears to be no difference between the formation of these ice fringes and the “ground ice” formed on wet soils, other than that in the latter a particle of gravel usually forms the nucleus to start the congelation. In both cases the moisture is brought to the surface by capillary action. When the rate of supply to the surface is more rapid than the loss by evaporation, and the air is at a sufficiently low temperature, ice is formed.

THE EXUDATION OF ICE FROM STEMS OF PLANTS

Abstract This paper deals with the formation of ice fringes upon the Dittany (Cunila mariana). The data presented are based upon experiments and observations in the field and in the laboratory. It was observed that the ice fringes are formed when the temperature falls to freezing point (o° C., 32° F.); but they are not a function of the hoar-frost which may be present upon the ground. The ice fringes do not form upon the side of a splinter which contains the pith or upon the line of fracture, but upon the outer woody surface. The formation of the ice fringe, however, is not a function of the surface condition of the stem. The stem is frequently found to be cracked, but usually no ice protrudes from the rifts. The growth of the ice fringe ceases when the ground is frozen to a depth of 2 to 3 cm., and when the moisture in the stem is frozen. The size of the ice fringes and the height to which they extend above the ground depend upon the rate of evaporation from the stem and upon the amount of moisture in the ground. Over 5 grammes of ice may be formed upon a single plant during a single night. Photographs are given of ice fringes formed upon stems which had been kept in the laboratory several months. They show that the ice may be formed upon stems without the roots. Hence the ice is not formed as a result of hydrostatic pressure exerted by the roots, which are perennial. All the observations are in agreement in showing that the moisture arises in the stem as the result of capillary attraction. The height (1 to 5 cm.) to which the moisture can rise within the stem is governed partly by the rate of evaporation from the surface. Microphotographs of thin sections of plants are given, which show the structure of stems of plants which do not form ice fringes; also microphotographs of sections of stems of plants which form ice fringes. It is shown that those plants which form ice fringes the most readily and in the greatest abundance have the most sap-tubes. The ice fringe is a composite of a number of very thin ribbons. In the laboratory the formation of the ice fringe was observed from its very beginning. The first stage in the production of the ice fringe consists of a single row of fine, hair-like filaments of ice. This row of ice filaments lengthens, up and down the stem. The filaments increase in number, thus forming a solid wedge-shaped tooth of ice, which constitutes the second stage of development. In the third stage of development the wedge-shaped tooth of ice widens and increases in length, as the result of freezing of the water which continues to soak out of the stem. There appears to be no difference between the formation of these ice fringes and the “ground ice” formed on wet soils, other than that in the latter a particle of gravel usually forms the nucleus to start the congelation. In both cases the moisture is brought to the surface by capillary action. When the rate of supply to the surface is more rapid than the loss by evaporation, and the air is at a sufficiently low temperature, ice is formed.

On national standards for gas measurement and gas-meters

This paper deals with the formation of ice fringes upon the Dittany (Cunila mariana). The data presented are based upon experiments and observations in the field and in the laboratory.It was observed that the ice fringes are formed when the temperature falls to freezing point (o° C., 32° F.); but they are not a function of the hoar-frost which may be present upon the ground.The ice fringes do not form upon the side of a splinter which contains the pith or upon the line of fracture, but upon the outer woody surface. The formation of the ice fringe, however, is not a function of the surface condition of the stem. The stem is frequently found to be cracked, but usually no ice protrudes from the rifts.The growth of the ice fringe ceases when the ground is frozen to a depth of 2 to 3 cm., and when the moisture in the stem is frozen.The size of the ice fringes and the height to which they extend above the ground depend upon the rate of evaporation from the stem and upon the amount of moisture in the ground. Over 5 grammes of ice may be formed upon a single plant during a single night.Photographs are given of ice fringes formed upon stems which had been kept in the laboratory several months. They show that the ice may be formed upon stems without the roots. Hence the ice is not formed as a result of hydrostatic pressure exerted by the roots, which are perennial.All the observations are in agreement in showing that the moisture arises in the stem as the result of capillary attraction. The height (1 to 5 cm.) to which the moisture can rise within the stem is governed partly by the rate of evaporation from the surface.Microphotographs of thin sections of plants are given, which show the structure of stems of plants which do not form ice fringes; also microphotographs of sections of stems of plants which form ice fringes. It is shown that those plants which form ice fringes the most readily and in the greatest abundance have the most sap-tubes.The ice fringe is a composite of a number of very thin ribbons. In the laboratory the formation of the ice fringe was observed from its very beginning. The first stage in the production of the ice fringe consists of a single row of fine, hair-like filaments of ice. This row of ice filaments lengthens, up and down the stem. The filaments increase in number, thus forming a solid wedge-shaped tooth of ice, which constitutes the second stage of development. In the third stage of development the wedge-shaped tooth of ice widens and increases in length, as the result of freezing of the water which continues to soak out of the stem.There appears to be no difference between the formation of these ice fringes and the “ground ice” formed on wet soils, other than that in the latter a particle of gravel usually forms the nucleus to start the congelation. In both cases the moisture is brought to the surface by capillary action. When the rate of supply to the surface is more rapid than the loss by evaporation, and the air is at a sufficiently low temperature, ice is formed.