Difference between the following
1) A moss and a fern
2) TMV and the pathogen of potato spindle tuber disease
1) A moss and a fern
2) TMV and the pathogen of potato spindle tuber disease
Ferns and mosses are both examples of "primitive plants," according to J. Stein Carter of the University of Cincinnati Biology Department. They have not developed all the specialized systems that modern plants have, although ferns are more highly developed than mosses.
Vascular Systems Mosses are not well adapted to living on dry land. Ferns do better at it. This is largely because while mosses do not have a vascular system, ferns do.
Spores Fern spores are produced in clusters underneath the leaves. Moss spores are produced in capsules on the tips of stalks among their shoots.
Appearance Ferns have large compound leaves divided into many leaflets. Mosses have no true leaves, just tiny green shoots. Some ferns can grow higher than 15 feet. Mosses are limited to about an inch.
Exceptions Club mosses have tiny true leaves with vascular systems. The extinct Lepidodendron was a giant club moss that looked like a tree. It could grow over 135 feet high.
TMV ---- Symptoms induced by Tobacco mosaic virus (TMV) are somewhat dependent on the host plant and can include mosaic, mottling (Figures 1 and 2), necrosis (Figures 3 and 4), stunting, leaf curling, and yellowing of plant tissues. The symptoms are very dependent on the age of the infected plant, the environmental conditions, the virus strain, and the genetic background of the host plant. Strains of TMV also infect tomato, sometime causing poor yield or distorted fruits, delayed fruit ripening, and nonuniform fruit color.
Hosts for TMV include tobacco (Figure 1), tomato (Figure 5), and other solanaceous plants. Currently, yield losses for tobacco due to TMV are estimated at only 1% because resistant varieties are routinely grown. In contrast, losses of up to 20% have been reported for tomato. In addition, poor fruit quality may reduce the value of the crop on the commercial fresh market.
pathogen of potato spindle tuber disease -----
Potato Spindle Tuber Viroid (PSTVd) is an EU listed quarantine pathogen of potatoes which causes stunting of the plant and malformation and cracking of tubers. The main host is potatoes but the disease also affects tomatoes and solanaceous ornamentals.Transmission and dispersal
The disease is mechanically transmitted by contact between healthy and diseased plants, tractor wheels, tools, etc. Within potato plants, it is found most readily in the upper leaves and tubers.
Transmission in true seed of potato depends upon the cultivar. PSTVd can pass through both the pollen and ovule.
Long Range dispersal mainly occurs through the movement of infected tubers and true seed.
PSTVd can also be spread by aphids. But this only occurs in the presence of Potato leaf roll virus (PLRV) and is unlikely to be a major problem in the UK.
Symptoms Mild strains generally cause no obvious symptoms in potatoes. However severe strains in sensitive cultivars may cause foliage to be spindly, very upright, with overlapping leaflets and sometimes with upward rolling of terminal leaflets. Plants will be stunted. Tubers may show the following deformities; small, elongated, cylindrical, spindle or dumb-bell-shaped, with prominent eyes evenly distributed over the tuber, and cracking. Sprouting is slower than in healthy tubers.
Vascular Systems
Mosses are not well adapted to living on dry land. Ferns do better at it. This is largely because while mosses do not have a vascular system, ferns do.
SporesFern spores are produced in clusters underneath the leaves. Moss spores are produced in capsules on the tips of stalks among their shoots.
AppearanceFerns have large compound leaves divided into many leaflets. Mosses have no true leaves, just tiny green shoots. Some ferns can grow higher than 15 feet. Mosses are limited to about an inch.
ExceptionsClub mosses have tiny true leaves with vascular systems. The extinct Lepidodendron was a giant club moss that looked like a tree. It could grow over 135 feet high.
TMV ---- Symptoms induced by Tobacco mosaic virus (TMV) are somewhat dependent on the host plant and can include mosaic, mottling (Figures 1 and 2), necrosis (Figures 3 and 4), stunting, leaf curling, and yellowing of plant tissues. The symptoms are very dependent on the age of the infected plant, the environmental conditions, the virus strain, and the genetic background of the host plant. Strains of TMV also infect tomato, sometime causing poor yield or distorted fruits, delayed fruit ripening, and nonuniform fruit color.
Hosts for TMV include tobacco (Figure 1), tomato (Figure 5), and other solanaceous plants. Currently, yield losses for tobacco due to TMV are estimated at only 1% because resistant varieties are routinely grown. In contrast, losses of up to 20% have been reported for tomato. In addition, poor fruit quality may reduce the value of the crop on the commercial fresh market.
pathogen of potato spindle tuber disease -----
Potato Spindle Tuber Viroid (PSTVd) is an EU listed quarantine pathogen of potatoes which causes stunting of the plant and malformation and cracking of tubers. The main host is potatoes but the disease also affects tomatoes and solanaceous ornamentals.Transmission and dispersal
The disease is mechanically transmitted by contact between healthy and diseased plants, tractor wheels, tools, etc. Within potato plants, it is found most readily in the upper leaves and tubers.
Transmission in true seed of potato depends upon the cultivar. PSTVd can pass through both the pollen and ovule.
Long Range dispersal mainly occurs through the movement of infected tubers and true seed.
PSTVd can also be spread by aphids. But this only occurs in the presence of Potato leaf roll virus (PLRV) and is unlikely to be a major problem in the UK.
Symptoms Mild strains generally cause no obvious symptoms in potatoes. However severe strains in sensitive cultivars may cause foliage to be spindly, very upright, with overlapping leaflets and sometimes with upward rolling of terminal leaflets. Plants will be stunted. Tubers may show the following deformities; small, elongated, cylindrical, spindle or dumb-bell-shaped, with prominent eyes evenly distributed over the tuber, and cracking. Sprouting is slower than in healthy tubers.
