Plant Pathology - Study Mode

[#876] In double fertilization, male gamete and secondary nucleus form
Correct Answer

(A) Endosperm

Explanation

Solution: In double fertilization, the male gamete and secondary nucleus form the Endosperm. 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). It begins when a pollen grain adheres to the stigma of the carpel, the female reproductive structure of a flower. The pollen grain then takes in moisture and begins to germinate, forming a pollen tube that extends down toward the ovary through the style. The cells of an unfertilized ovule are 8 in number and arranged in the form of 3+2+3 (from top to bottom) i.e. 3 antipodal cells, 2 polar central cells, 2 synergids & 1 egg cell.

[#877] Mineralisation releases nutrients in soils are tide up in
Correct Answer

(C) Organic matter

Explanation

Solution: Mineralization releases nutrients in soils that are tied up in Organic matter. Mineralization is the phrase used to describe the process whereby organic forms of nitrogen (N) in the soil are converted to available forms of N. This process is driven by microorganisms present in the soil decomposing organic matter for their energy supply. Soil organic matter (SOM) mineralization is an important process in which carbon (C) and nutrients are transformed into CO 2 and plant-available forms of nitrogen (N), phosphorus (P) and sulphur (S).

[#878] The relay pump theory was given by
Correct Answer

(D) Godlewski

Explanation

Solution: The relay pump theory was given by Godlewski. Godlewski (1884) proposed his clambering or relay-pump theory to explain the vertical movement of water through the plant. He thought that a rhythmic change in the water potential of the living cells like the xylem parenchyma and medullary rays caused a pumping action to raise water vertically against gravity.

[#879] Photosynthetic synthesis of carbohydrates uses CO 2 and
Correct Answer

(A) Water in the presence of sunlight with the help of chlorophyll

Explanation

Solution: Photosynthetic synthesis of carbohydrates uses CO 2 and Water in the presence of sunlight with the help of chlorophyll. Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy, through cellular respiration. Some of this chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water.

[#880] Sterility mosaic disease of pigeonpea spread by
Correct Answer

(D) Mites

Explanation

Solution: Sterility mosaic disease of pigeonpea spread by Mites. The agent of sterility mosaic, a disease that is a major constraint on pigeonpea (Cajanus cajan) production in the Indian subcontinent, is transmitted by the eriophyid mite, Aceria cajani. Sterility mosaic disease (SMD), caused by Pigeonpea sterility mosaic virus (PPSMV), is the economically most important viral disease in India, causing an estimated annual loss of more than US$300 million.