Table of Contents
Which organism does not directly cause disease in plants?
A plant species that does not show disease when infected with a pathogen is referred to as a non-host plant species for that pathogen. Organisms that do not cause disease on any plant species, such as the saprophytic bacterial species Pseudomonas putida, are referred to as non-pathogens.
What is the physical basis of the phototropic response?
What is the physical basis of the phototropic response? Auxin is asymmetrically distributed in shoots because the auxin on the side of the plant facing the source of light is destroyed. Where does the majority of stem growth in a plant occur?.
Which of the following is a response in plants to a water deficit?
Drought stress induces various biochemical and physiological responses in plants. Among them, stomata closure in response to water deficit is the best-known physiological plant response. Stomata closure decreases water loss from leaves.
How does auxin produce Phototropism quizlet?
How does auxin produce phototropism? Auxin accumulates in cells on the side of the plant facing the source of light and stimulates their elongation. Auxin accumulates in cells on the side of the plant facing the source of light and causes them to shorten.
What causes disease in plants?
Infectious plant diseases are caused by living (biotic) agents, or pathogens. These pathogens can be spread from an infected plant or plant debris to a healthy plant. Microorganisms that cause plant diseases include nematodes, fungi, bacteria, and mycoplasmas.
What are the examples of plant diseases?
bacterial aster yellows. bacterial wilt. blight. fire blight. rice bacterial blight. canker. crown gall. rot. basal rot. scab.
Which hormone triggers the flowering process?
Florigen (or flowering hormone) is the hypothesized hormone-like molecule responsible for controlling and/or triggering flowering in plants. Florigen is produced in the leaves, and acts in the shoot apical meristem of buds and growing tips. It is known to be graft-transmissible, and even functions between species.
Which of these plant hormones is not typically considered a growth promoting substance?
Abscisic acid is the plant hormone which is not typically considered a growth promoting hormone.
How do plant and animal hormones differ?
The main difference between animal and plant hormones is that animal hormones are complex organic substances, whereas plant hormones are simple organic substances. Furthermore, animal hormones diffuse through the blood, while plant hormones diffuse through xylem and phloem.
Which of the following is not required for plant growth?
Explanation: Plants may absorb a number of minerals that are not essential for their growth. Iodine is a non essential mineral element. Iron, zinc and potassium are essential mineral elements.
Which one does not show transpiration?
Hint: The name of the plants which do not show transpiration are Cabomba, Fanwort, Brittle Naiad, Marine Naiad, and many more. These plants are surrounded by water every time and due to this reason, pollination is also done by the water.
What causes water stress in plants?
Water stress is primarily caused by a water deficit, such as a drought or high soil salinity. Plants experience water stress either when the water supply to their roots becomes limiting, or when the transpiration rate becomes intense.
How do Auxins cause plant shoots to grow towards light?
It grows because the auxin causes the cells to elongate on the shaded side, so this side grows more. This unequal growth of the two sides, results in the growth of the stem towards the light. If lit from above, the plant will grow upwards. Auxins have the opposite effect on root cells.
What color maximizes seed germination?
Chlorophyll is what makes plants green and allows plants absorb light energy and turn it into food. Since chlorophyll is green, colors on the opposite side of the color spectrum are most efficient for plant growth including red and blue.
How does auxin exert its effect on plant cells?
Auxins promote stem elongation, inhibit growth of lateral buds (maintains apical dominance). Auxin is a plant hormone produced in the stem tip that promotes cell elongation. Auxin moves to the darker side of the plant, causing the cells there to grow larger than corresponding cells on the lighter side of the plant.
What are the four common plant diseases?
Common Plant Diseases Black Spot. Other Leaf Spots. Powdery Mildew. Downy Mildew. Blight. Canker.
What is the most common plant disease?
Most Common Plant Diseases and Solutions Powdery Mildew. Most powdery mildew are very host specific, mildew on cucumbers will not infect roses. Black Spot. This is a common fungal disease of roses. Bacterial Canker or Blight. Shot Hole. Black Knot. Rust. Late Blight / Early Blight. Apple Scab.
What are the plant diseases caused by fungi?
Leaf Diseases Caused by Fungi and Bacteria Leaf Spots. Leaf spots (other names: anthracnose, scab, leaf blotch, shot hole) are usually rather definite spots of varying sizes, shapes and colors. Leaf Blights. Rusts. Powdery Mildew. Downy Mildew.
What are the bacterial diseases in plants?
Control Some bacterial diseases of plants disease causative agent hosts Granville wilt Pseudomonas solanacearum tobacco, tomato, potato, eggplant, pepper, and other plants fire blight Erwinia amylovora apple and pear wildfire of tobacco Pseudomonas syringae tobacco.
What are the common diseases in nursery plants?
A brief description of the various diseases and their control measures in nursery is given below: Damping off: Leaf Web Blight. Colletotrichum Leaf spot and blight: Alternaria Leaf spot and blight: Pseudocercospora Leaf spot: It is caused by Pseudocercospora subsessilis. Powdery Mildew: Other Foliar Diseases:.
What is a non communicable plant disease?
Abiotic or non-infectious diseases: They cannot spread from plant to plant, but are very common and should be considered when assessing the health of any plant. Examples of abiotic diseases include nutritional deficiencies, soil compaction, salt injury, ice, and sun scorch (Figure 61).
What are gibberellins?
Gibberellins are a group of plant hormones responsible for growth and development. They are important for initiating seed germination . Low concentrations can be used to increase the speed of germination, and they stimulate cell elongation so plants grow taller. They are naturally produced by barley and other seeds.
Is auxin flowering hormone?
Auxins were the first of the major plant hormones to be discovered. The (dynamic and environment responsive) pattern of auxin distribution within the plant is a key factor for plant growth, its reaction to its environment, and specifically for development of plant organs (such as leaves or flowers).
Which is main function of cytokinin?
Cytokinin is a hormone whose main function is induction of cell division and delay in senescence.
What are auxins and gibberellins?
gibberellin: any of a class of diterpene plant growth hormones that stimulate shoot elongation, seed germination, and fruit and flower maturation. auxin: a class of plant growth hormones that is responsible for elongation in phototropism and gravitropism and for other growth processes in the plant life cycle.
What are the 5 plant hormones?
Since 1937, gibberellin (GA), ethylene, cytokinin, and ab- scisic acid (ABA) have joined auxin as phytohormones, and together, they are regarded as the “classical five” (Fig- ure 1).
