Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

The compensation point is the value of a factor where there is photosynthesis equal to the rate of respiration.
The light compensation point (I_c) is the light intensity on the light curve where the rate of photosynthesis exactly matches the rate of cellular respiration.
At this point, the uptake of CO₂ through photosynthetic pathways is equal to the respiratory release of carbon dioxide, and the uptake of O₂ by respiration is equal to the photosynthetic release of oxygen.

Embryo sac is part of the female reproductive system.
The female gametophyte develops within the ovule and generally consists of three antipodal cells, one central cell, two synergid cells and one egg cell.
The female gametophyte is also commonly called the embryo sac or megagametophyte.

Non-essential but useful nutrients for plants would include vanadium and sodium.
Vanadium and Sodium are non-essential but useful nutrients for plants. Plants require 17 essential nutrients for their growth and development, but vanadium and sodium are not on that list. Vanadium is a multivalent redox-sensitive metal, low levels of vanadium elevate plant height, root length, and biomass production due to enhanced chlorophyll biosynthesis, seed germination and also for essential element uptake.
Sodium is needed by a few varieties of plants to help concentrate carbon dioxide, but in trace amounts to promote metabolism.

De Herelle discovered Bacteriophage.
A bacteriophage, also known informally as a phage, is a duplodnaviria virus that infects and replicates within bacteria and archaea.
De Herelle called the virus a bacteriophage, a bacteria-eater. He also recorded a dramatic account of a man suffering from dysentery who was restored to good health by the bacteriophages.
It was de Herelle who conducted much research into bacteriophages and introduced the concept of phage therapy.

Double fertilization is a fusion of one male gamete with an egg and the other with secondary nucleus.
Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm).
The process of double fertilization is a unique biological process in which one sperm fuses with the egg to produce the embryo while the second fuses with the central cell to form the endosperm, a nutritive tissue needed for the growth of the succeeding generation.

Potato wart is an example of an Endemic type of disease.
Synchytrium endobioticum is a chytrid fungus that causes potato wart disease or black scab. It also infects some other plants of the genus Solanum, though potato is the only cultivated host.
Potato wart is a soil-borne fungus that can remain dormant in a field for more than 40 years. Cool and wet soils are conducive to potato wart disease development. The infected plant cells swell, divide and surround the dividing zoospores resulting in the wart.

Calvin cycle is supported by light.
The Calvin cycle uses the chemical energy of ATP and the reducing power of NADPH from the light-dependent reactions to produce sugars for the plant to use.
The Calvin cycle thus happens when light is available independent of the kind of photosynthesis, CAM plants store malic acid in their vacuoles every night and release it by day to make this process work.

The permeability of protoplasm is accelerated by K (Potassium).
Potassium (K⁺) is of paramount importance in plant cell physiology. K⁺ is an essential macronutrient that fulfills critical functions related to enzyme activation, osmotic adjustment, turgor generation, cell expansion, regulation of membrane electric potential, and pH homeostasis.

Micrografting is used to produce plants free from viruses.
An innovative technique of micrografting was developed by Murashige et al. (1972) for the production of uniform virus-free plants on a commercial scale in a controlled environment.
They grafted a small apical shoot of citrus to the top of a decapitated seedling grown in vitro. Micropropagation can be used to produce disease-free plants. It produces rooted plantlets ready for growth, and saves time for the grower, instead of seeds or cuttings.

RuBISCO content of chloroplast is 16%.
It is an enzyme involved in the first major step of carbon fixation, a process by which atmospheric carbon dioxide is converted by plants and other photosynthetic organisms to energy-rich molecules such as glucose.
RuBisCO is slow, fixing only 3-10 carbon dioxide molecules each second per molecule of enzyme. The reaction catalyzed by RuBisCO is, thus, the primary rate-limiting factor of the Calvin cycle during the day.