Fertilization is an important event in angiosperm, which...

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Q.1

ICAR AIEEA PG 2024 - Plant Sciences (Q.24)

MCQ (Single Correct) +4 −1

The characteristic features of monocot seeds include-

(A) Seeds germinate bearing a short axis called Plumule and Radicle.

(B) Plumule and Radicle are enclosed in a sheath called Coleoptile and Coleorhiza, respectively.

(C) The radicle grows downward and develops into the root system.

(D) The cotyledon of the seeds of the monocot crop Sorghum (Jowar) is known as 'Husk'.

Choose the correct answer from the options given below:

एकबीजपत्री (monocot) बीजों के विशिष्ट लक्षणों में शामिल हैं:

(A) बीज अंकुरित होकर एक छोटा अक्ष धारण करते हैं जिसे प्रांकुर (Plumule) और मूलांकुर (Radicle) कहा जाता है।

(B) प्रांकुर और मूलांकुर क्रमशः प्रांकुरचोल (Coleoptile) और मूलांकुरचोल (Coleorhiza) नामक आवरण में बंद होते हैं।

(C) मूलांकुर नीचे की ओर बढ़ता है और मूल तंत्र (root system) के रूप में विकसित होता है।

(D) एकबीजपत्री फसल ज्वार (Sorghum) के बीजों के बीजपत्र को 'भूसी' (Husk) के रूप में जाना जाता है।

नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

(A), (B) and (C) only केवल (A), (B) और (C) (A), (B) and (D) only केवल (A), (B) और (D) (A), (C) and (D) only केवल (A), (C) और (D) (B), (C) and (D) only केवल (B), (C) और (D)

Morphology of Monocot Seeds:

Statement (A) is CORRECT: The embryonal axis bears the plumule (future shoot) and radicle (future root).
Statement (B) is CORRECT: In monocots/grasses, the plumule is enclosed in a protective cylindrical sheath called the coleoptile, and the radicle is enclosed in the coleorhiza.
Statement (C) is CORRECT: Upon germination, the radicle penetrates downward into the soil to establish the primary seminal root system.
Statement (D) is INCORRECT: In monocot seeds (including sorghum, maize, wheat), the single shield-shaped cotyledon is called the Scutellum, which absorbs nutrients from the endosperm. 'Husk' refers to the protective glumes/palea/lemma, not the cotyledon.

Therefore, statements (A), (B), and (C) are correct. Correct Answer: Option 1 ((A), (B) and (C) only).

विस्तृत व्याख्या:

Morphology of Monocot Seeds (एकबीजपत्री बीज की संरचना):

Statement (A) is CORRECT: The embryonal axis bears the plumule (future shoot) and radicle (future root).
Statement (B) is CORRECT: In monocots/grasses, the plumule is enclosed in a protective cylindrical sheath called the coleoptile, and the radicle is enclosed in the coleorhiza.
Statement (C) is CORRECT: Upon germination, the radicle penetrates downward into the soil to establish the primary seminal root system.
Statement (D) is INCORRECT: In monocot seeds (including sorghum, maize, wheat), the single shield-shaped cotyledon is called the Scutellum (स्कुटेलम), which absorbs nutrients from the endosperm. 'Husk' refers to the protective glumes/palea/lemma, not the cotyledon.

Therefore, statements (A), (B), and (C) are correct. Correct Answer: Option 1 ((A), (B) and (C) only).

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.2

ICAR AIEEA PG 2024 - Plant Sciences (Q.33)

MCQ (Single Correct) +4 −1

Fertilization is an important event in angiosperm, which involves several critical activities. Below are a few major steps of fertilization in plants. Arrange them from the beginning to the last, systematically:

(A) Pollen germination.

(B) Anthesis followed by pollination.

(C) Fertilization.

(D) Penetration of the ovule.

Choose the correct answer from the options given below:

आवृतबीजी (angiosperms) में निषेचन एक महत्वपूर्ण घटना है, जिसमें कई महत्वपूर्ण गतिविधियाँ शामिल हैं। नीचे पौधों में निषेचन के कुछ प्रमुख चरण दिए गए हैं। उन्हें आरंभ से अंत तक व्यवस्थित कीजिए:

(A) परागकण का अंकुरण (Pollen germination)

(B) प्रस्फुटन (Anthesis) और उसके बाद परागण (Pollination)

(C) निषेचन (Fertilization / द्विनिषेचन)

(D) बीजांड में प्रवेश (Penetration of the ovule)

नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

(A), (B), (C), (D) (A), (B), (C), (D) (A), (C), (B), (D) (A), (C), (B), (D) (B), (A), (D), (C) (B), (A), (D), (C) (C), (B), (D), (A) (C), (B), (D), (A)

Sequence of Reproductive Events Leading to Fertilization:

Anthesis followed by pollination: Floral opening (anthesis) allows anther dehiscence and transfer of mature pollen grains onto the receptive stigma (pollination).
Pollen germination: The pollen grain absorbs moisture and nutrients on the stigmatic surface, germinating to form a pollen tube.
Penetration of the ovule: The elongated pollen tube grows down the style, enters the ovary, and penetrates the ovule (commonly through the micropyle - porogamy) into the embryo sac.
Fertilization: Syngamy occurs (one male gamete fuses with the egg cell to form the diploid zygote, and the other fuses with the central polar nuclei to form triploid endosperm - double fertilization).
Correct chronological order: (B), (A), (D), (C).
Correct Answer: Option 3.

विस्तृत व्याख्या:

Sequence of Reproductive Events Leading to Fertilization (पादप निषेचन के चरण):

Anthesis followed by pollination: Floral opening (anthesis) allows anther dehiscence and transfer of mature pollen grains onto the receptive stigma (pollination).
Pollen germination: The pollen grain absorbs moisture and nutrients on the stigmatic surface, germinating to form a pollen tube.
Penetration of the ovule: The elongated pollen tube grows down the style, enters the ovary, and penetrates the ovule (commonly through the micropyle - porogamy) into the embryo sac.
Fertilization: Syngamy occurs (one male gamete fuses with the egg cell to form the diploid zygote, and the other fuses with the central polar nuclei to form triploid endosperm - double fertilization).
Correct chronological order: (B), (A), (D), (C).
Correct Answer: Option 3.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.3

ICAR AIEEA PG 2024 - Plant Sciences (Q.111)

Statement Based +4 −1

Given below are two statements

Statement (I) : Double fertilization involves the fusion of two sperm cells with two egg cells.

Statement (II) : In double fertilization, one sperm cell fuses with the egg cell, while the other sperm cell fuses with the two polar nuclei.

In light of the above statements, choose the most appropriate answer from the options given below:

नीचे दो कथन दिए गए हैं

कथन (I) : द्विनिषेचन (Double fertilization) में दो शुक्राणु कोशिकाओं (नर युग्मकों) का दो अंड कोशिकाओं के साथ संलयन शामिल है।

कथन (II) : द्विनिषेचन में, एक शुक्राणु कोशिका (नर युग्मक) अंड कोशिका के साथ संलयित होती है, जबकि दूसरी शुक्राणु कोशिका दो ध्रुवीय केंद्रकों (polar nuclei) के साथ संलयित होती है।

उपरोक्त कथनों के आलोक में, नीचे दिए गए विकल्पों में से सबसे उपयुक्त उत्तर चुनिए:

Both Statement (I) and Statement (II) are true कथन (I) और कथन (II) दोनों सत्य हैं Both Statement (I) and Statement (II) are false कथन (I) और कथन (II) दोनों असत्य हैं Statement (I) is true but Statement (II) is false कथन (I) सत्य है लेकिन कथन (II) असत्य है Statement (I) is false but Statement (II) is true कथन (I) असत्य है लेकिन कथन (II) सत्य है

Double Fertilization in Angiosperms:

Discovered by S.G. Nawaschin in Lilium and Fritillaria.
The pollen tube discharges two non-motile male gametes (sperm cells) into the embryo sac:

Syngamy (Generative fertilization): One haploid sperm cell ($n$) fuses with the haploid egg cell ($n$) to form the diploid zygote ($2n$), which develops into the embryo.
Triple Fusion (Vegetative fertilization): The second haploid sperm cell ($n$) migrates to the central cell and fuses with the two haploid polar nuclei ($n + n$) to produce the triploid primary endosperm nucleus (PEN, $3n$), which forms nutritive endosperm tissue.
- Statement (I) is FALSE: Double fertilization does NOT involve two egg cells (an angiosperm embryo sac contains only one single egg cell).
Statement (II) is TRUE: Accurately describes syngamy and triple fusion.

Therefore, Statement (I) is false but Statement (II) is true. Correct Answer: Option 4.

विस्तृत व्याख्या:

Double Fertilization in Angiosperms (आवृतबीजी में द्विनिषेचन - Nawaschin, 1898):

Discovered by S.G. Nawaschin in Lilium and Fritillaria.
The pollen tube discharges two non-motile male gametes (sperm cells) into the embryo sac:

Syngamy (Generative fertilization): One haploid sperm cell ($n$) fuses with the haploid egg cell ($n$) to form the diploid zygote ($2n$), which develops into the embryo.
Triple Fusion (Vegetative fertilization): The second haploid sperm cell ($n$) migrates to the central cell and fuses with the two haploid polar nuclei ($n + n$) to produce the triploid primary endosperm nucleus (PEN, $3n$), which forms nutritive endosperm tissue.
- Statement (I) is FALSE: Double fertilization does NOT involve two egg cells (an angiosperm embryo sac contains only one single egg cell).
Statement (II) is TRUE: Accurately describes syngamy and triple fusion.

Therefore, Statement (I) is false but Statement (II) is true. Correct Answer: Option 4.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report