Plant Pathology - Study Mode
[#476] Embryo sac is monosporic when it dovelops from
Correct Answer
(A) One of the four megaspores of a megaspore mother cell
Explanation
Solution: The embryo sac is monosporic when it develops from one of the four megaspores of a megaspore mother cell. In monosporic development, the egg apparatus is organized from a group of four nuclei at the micropylar pole of the syncytial embryo sac. These nuclei are derived from the chalazal megaspore of the tetrad. One cell of the nucellus undergoes meiosis to produce four megaspores. One megaspore survives and undergoes three rounds of the free nuclear division followed by cellularization to produce an embryo sac consisting of 8 nuclei in 7 cells. At the micropylar end, two peripheral cells develop into synergids (which attract the pollen tube for sperm delivery), and the third cell differentiates into the egg cell.
[#477] Nephantis serenopa is responsible for damage of
Correct Answer
(C) Coconut
Explanation
Solution: Nephantis serenopa is responsible for the damage to the Coconut. Nephantis serinopa is the only species within the genus Nephantis. The wingspan is 20 - 28 mm. The forewings are pale greyish-ochreous, with some fine scattered blackish scales and with the extreme costal edge whitish. The first discal stigma is raised, and dark fuscous, the plical and second discal indistinct, indicated by two or three dark fuscous scales, the plical obliquely before the first discal. The larvae conceal themselves beneath galleries of web and excreta on the under-surface of the leaves of the coconut palm.
[#478] PR Proteins accumulate in the
Correct Answer
(D) Apoplast & vacuole
Explanation
Solution: PR Proteins accumulate in the Apoplast & vacuole. Pathogenesis-related (PR) proteins are proteins produced in plants in the event of a pathogen attack. These are structurally diverse groups of plant proteins that are toxic to invading fungal pathogens. They are widely distributed in plants in trace amounts but are produced in much greater concentrations following pathogen attack or stress. Pathogenesis-related proteins are a class of proteins that accumulate in response to biotic and abiotic stresses to protect plants from damage in the apoplast and vacuole.
[#479] Embryo sac occurs in
Correct Answer
(C) Ovule
Explanation
Solution: The embryo sac occurs in Ovule. The embryo sac develops within the ovule surrounded by the nucellus, which is in turn surrounded by the integuments. One cell of the nucellus undergoes meiosis to produce four megaspores. A mature ovule consists of a food tissue covered by one or two future seed coats, known as integuments. A small opening (the micropyle) in the integuments permits the pollen tube to enter and discharge its sperm nuclei into the embryo sac, a large oval cell in which fertilization and development occur.
[#480] Select the nematicides group which are nonfumigant in nature
Correct Answer
(D) Aldicarb and Phorate
Explanation
Solution: Aldicarb and Phorate are the nematicides group which are nonfumigant in nature. Non-fumigant nematicides available for vegetable production in Florida include two broad categories, chemical nematicides, and biological nematicides. Aldicarb is a carbamate insecticide that is the active substance in the pesticide Temik. It is effective against thrips, aphids, spider mites, lygus, fleahoppers, and leafminers, but is primarily used as a nematicide. Phorate is an organophosphate used as an insecticide. It is very toxic both for target organisms and for mammals including humans.