Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

For the synthesis of a molecule of glucose, the requirement of ATP and NADPH is 18 and 12 respectively.
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.
These substrates are used in a series of reduction-oxidation reactions to produce glucose. The reactions for the formation of a molecule of glucose take the products (18ATP and 12 NADPH) of light-dependent reactions.

All the pairs given in the options are correctly matched.
A. Holo stem parasite - Cuscuta reflexa.
Cuscuta spp. are stem parasites that naturally graft to their host plants to extract water and nutrients; multiple adjacent hosts are often parasitized by one or more Cuscuta plants simultaneously, forming connected plant clusters.
B. Stem semiparasite - Dendrophthoe falcate
Dendrophthoe falcate is one of the hemiparasitic plants that belong to the mistletoe family Loranthaceae. It is the most common of all the mistletoes that occur in India. D.falcata bears grey bark, thick coriaceous leaves variable in shape with stout flowers.
C. Holo root parasite - Orobanche
Broomrapes or Orobanche are aggressive root parasitic weeds, which attack strategic food crops, such as legumes and vegetables, and threaten the livelihood of many nations.

The fore-runner of the male gamete is the Microspore mother cell.
Microspores are land plant spores that develop into male gametophytes, that is pollen in plants.
The male gametophyte gives rise to sperm cells, which are used for fertilization of an egg cell to form a zygote. Microspores are haploid and are produced from diploid microsporocytes by meiosis.

The C₄ cycle was discovered in Sugarcane.
C₄ carbon fixation is one of three known photosynthetic processes of carbon fixation in plants.
It owes the name to the 1960's discovery by Marshall Davidson Hatch and Charles Roger Slack in a sugarcane plant that refers when supplied with ¹⁴CO₂, incorporates the ¹⁴C label into four-carbon molecules first.

Genotypically the pollen grains produced by anthers belong to many types.
Several types of pollen grains are formed by anthers in plants. The anther usually contains four pollen sacs which are responsible for producing pollen grains.
Pollen grains emerge from sporogenous tissues within the anther. Each sporogenous tissue cell inside the anther can produce pollen grains.

Sodium nitrate supplies water supplying a water-soluble form of nitrogen without altering the pH of the soil. It contains 16% of nitrogen.
Calcium nitrate fertilizer is a water-soluble chemical solution that provides plants with supplemental calcium and nitrogen. Its nitrogen content is about 15%.
Potassium nitrate fertilizer is a water-soluble fertilizer with high potassium and nitrogen content along with an optimal amount of sodium, its nitrogen content is 13%.
Urea is the most important nitrogenous fertilizer and is widely used also because of its high Nitrogen content which is about 46%.

ATP formation in chloroplast and mitochondrion is explained by the Chemi-osmotic theory of Mitchell.
The chemiosmotic theory states that the transfer of electrons down an electron transport system through a series of oxidation-reduction reactions releases energy. This energy allows certain carriers in the chain to transport hydrogen ions (H⁺ or protons) across a membrane.
Mitchell's theory stated that the electron transport chain and ATP synthesis are embedded in the same membrane, that the membrane is impermeable to protons, that compounds involved in the electron transport chain and ATP synthesis are in contact with one another or the other side of the membrane, that there is an exchange of protons across the membrane, leading to the synthesis of ATP.

The total number of meiotic divisions required for forming 100 zygotes/100 grains of wheat is 125.
A zygote is formed by the combination of male and female gametes, which that means for 100 zygotes, 100 male and female gametes will be required.
Male gametes are formed by the process of microsporogenesis, and in this, 1 cycle leads to the formation of 4 pollen grains.
For 100 microspores, $$\frac{{100}}{4}$$ = 25 cycles of meiosis will be done.
Now, female gametes are formed by the process of megasporogenesis, and for each active megaspore, 1 cycle of meiotic division is required. Thus, for 100 megaspores, 100 cycles of meiosis will be done.
That is ultimate, 100 + 25 = 125 meiotic division will produce 100 grains or zygotes.

The bunchy top of papaya (caused by MLO) is spread by Leaf hoppers.
Papaya Bunchy Top Disease was first discovered in 1931 in Puerto Rico.
Bunchy Top Disease in Papaya is the most serious disease that severely limits commercial production. The disease is caused by Mycoplasma organism (MLOs) and is vectored by a leafhopper Empoasca papaya.
It is vectored by two species of leafhopper, Empoasca papayae Oman (Sein) and Empoasca stevensi Young. The species that vector the disease is dependent on the geographical location.

Plants absorb nutrients mostly through Roots.
Mineral nutrients are usually obtained from the soil through plant roots, but many factors can affect the efficiency of nutrient acquisition.
During diffusion, roots grow throughout the profile and use up nutrients directly around the root system and the root hairs. As the concentration of nutrients around the root system drops, nutrients from higher concentrated areas move or diffuse toward low concentration areas and the roots.