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Correct Answer is : (c) ABA

Low temperature treatment given to the seeds/seedlings to induce early flowering is called as vernalisation.

Indole Acetic Acid.

(b) a few days

Factors Affecting photosynthesis :

• According to Blackman‟s law of limiting factors “if a chemical process is affected by more than one factors, then the rate of the process will directly depend on the factor nearest to its minimal value”. 
• As photosynthesis is affected by number of internal (No., Size, and orientation of leaves, merophyll cells & chloroplasts etc.) and external factors (light, CO₂ Conc, temp., soil water etc.), it‟s rate will also directly depend on the factor nearest to its minimal value.
• Light intensity and quality affect rate of photosynthesis. Light of wavelengths 400 nm - 700 nm is effective for photosynthesis. With increase in light intensity, rate of photosynthesis increases, but at higher light intensity rate decreases either due to the destruction of chlorophyll or due to other factors that becomes limiting.
• Only dark reaction is affected by temperature as it is enzyme catalysed reaction and enzymes remain inactive at low temp. while become denatured at high temperatures.
• Rate of photosynthesis increases with increase in CO₂ Con. upto a certain limit (upto 500 µl/L in C₃ & 360 µl/L in C₄ plants). 
• Lower availability of soil water causes stomatal closure causing decreased supply of CO₂, hence decrease in photosynthesis.

Factors affecting photosynthesis : 

1. Light 

2. Carbon dioxide 

3. Temperature 

4. Water

Growth Promoters : Involved in growth promoting activities like-cell division, cell enlargement etc.

Sudden elongation of the internodes just prior to flowering is called as bolting.

(c) Vemalizatiqn increase the vegetative period of the plant

(d) bound auxin

If a chemical process is affected by more than one factor, then its rate will be determined by the factor which is nearest to its minimal value. It is the factor which directly affects the process if its quantity is changed.

Growth inhibitors : Involved in growth inhibiting activities like-dormancy, abscission etc.

Types :

1. Ethylene

2. Abscissic Acid (ABA)

Phenomena in which the apical bud suppresses the growth of lateral buds is called as apical dominance.

(c) long day plants

The factors which govern the appearance of reproductive phase of flowering in angiosperms are: 

(i) Completion of juvenile phase and attainment of adult phase. 

(ii) Exposure to suitable day length. 

(iii) Proper temperature.

The response of a plant to varying photoperiods of light is called photoperiodism.

When “a process is conditioned as to its rapidity by a number of separate factors, the rate of the process is limited by the pace of the slowest factor”.

Depending upon  the duration of light required for photoperiodic responses plants can be categorized as :

(i) Long day Plants (LDPs) : Requires exposure of light more than critical duration. 

Ex. Radish, sugar beet.

(ii) Short Day Plants(SDPs) : Requires exposure of light less than critical duration. 

Ex- Tobacco, Chrysanthemum

(iii) Day Neutral Plants (DNPs) : Flowering not influenced by duration of light. 

Ex. Tomato, Cotton etc.

• The knowledge of photoperiodism plays an important role in hybridisation experiments. 
• Photoperiodism is an excellent example of physiological pre-conditioning that is using an external factor to induce physiological changes in the plant.

Importance of photoperiodism: 

(i) Photoperiodism determines the season in which a particular plant shall come to flower. 

(ii) Knowledge of photoperiodic effect is useful in keeping some plants in vegetative growth, to obtain higher yield of tubers, rhizomes etc., or keep the plant in reproductive stage. 

(iii) The phenomenon has helped the plant breeders in effecting cross-breeding in plants. 

(iv) A plant can be made to flower throughout the year under greenhouse conditions if a favourable photoperiod is provided to it.

(b) Gamer and Allard

Growth hormone inducing flowering in plants is called as florigen. It helps in overcoming apical dominance.

Kinetin is a substance which promotes cell division (cytokinesis).

Ethylene enhances the respiration rate during ripening of the fruits. This rise in rate of respiration is called respiratory climactic.

The response of a plant varying photo-periods of light is called photoperiodism.

Plants are grouped into three types;

• Long day plants eg- spinach, beetroot
• Short day plants eg- tobacco, soybean
• Day-neutral plants eg- tomato, chilli

The substances similar to auxins have been synthesized in the laboratory are called synthetic auxins.

Example: IBA, NAA.

Synthetic auxins are;

2,4 – D (2, 4 dichlorophenoxy acetic acid) used as weedicide. NAA (Napthalene acetic acid) – Initiates floweripg in pineapple.

2, 4-D and 2, 4, 5-T.

Practical applications of Gibberellins

• Bolting and flowering brings about stem elongation called bolting and formation of flowers in Cabbage and cauliflower.
• Breaking dormancy: They break dormancy and promote germination.
• Parthenocarpy: Induce the formation of parthenocarpic fruits and more potent than auxins.
• Synthesis of enzyme amylase: They induce synthesis of a amylase in the endosperms of germinating grains.

• They promote cell elongation in stem and coleoptile.
• At higher concentrations auxins inhibit the elongation of roots but induce more lateral roots. Promotes growth of root only at extremely low concentrations.

• 2,4 – Dichloro Phenoxy Acetic Acid (2,4 – D) 
• 2, 4, 5 – Trichloro Phenoxy Acetic Acid (2,4,5 – T)

• Apical dominance – used for long term storage of potato tubers.
• Parthenocarpy – used in the production of seed¬less fruits
• Abscission – to prevent premature fruitful and defoliation of cabbage.
• Weedicide – to destroy dicots in crop cultivation and Lawn grass patches.

Synthetic auxins are widely used in

• Inducing rooting
• Parthenocarpy
• Weed Control
• Inhibition of Abscission.

Functions of Auxins: 

(i) Cell enlargement: Auxins promote elongation and growth of stems and roots enlargement of many fruits by stimulating cell enlargement. The auxins cause cell enlargement by solubilization of carbohydrates, loosening of microfibrils synthesis of more wall materials, increased membrane permeability and respiration. 

(ii) Cell division in cambium: Auxin is responsible for initiation and promotion of cell division in cambium. The reactivation of cambium in the growing season is apparently triggered by IAA moving from the developing shoot buds. 

(iii) Cell division and tissue culture: In tissue culture auxins initiate and promote cell division, and result in the formation of callus. 

(iv) Root growth and root initiation: Auxins promote root growth only at extremely low concentration. At higher concentration, auxin is suitable for shoot elongation.

Correct answer is (b) gibberellins

Correct option is (b) Ethylene

 A change in the turgidity of guard cells results in closing or opening of stomata. The inner wall of the guard cell; towards the stomatal aperture; is thick and elastic. An increase in turgidity results in the thin outer walls to bulge out. This forces the inner wall into a crescent shape and results in opening of stoma. The orientation of the microfibrils in the cell walls of the guard cells also helps in opening of stomata. These meicrobifibrils are radially oriented and thus make it easy for the stoma to open up. A loss in turgidity of the guard cells, leads to resumption of shape of the elastic inner wall of the guard cell and the stoma closes.

Normally stomata are open in the day time and close during the night.

The immediate cause of the opening or closing of the stomata is a change in the turgidity of the guard cells. The inner wall of each guard cell, towards the pore is thick and elastic. When turgidity increases within the two guard cells flanking each stomatal aperture thin outer walls bulge out and force the inner walls into a crescent shape. The opening of the stoma is also aided due to the orientation of the microfibrils in the cell walls of the guard cells.

Correct answer is (c) Ethylene

Correct option is (a) closes almost completely

मनुष्यों में ऑक्सीजन तथा काबर्न – डाइऑक्साइड के परिवहन को श्वसन कहते है | यह प्रक्रिया फैफडो द्वारा संपन्न कि जाति है |फैफडो में साँस के द्वारा पहुची हुई वायु में से हीमोग्लोबिन (लाल रक्त कण ) ऑक्सीजन को ग्रहण कर के शरीर की सभी कोशिकाओ तक पहुचता है | इस प्रकार ऑक्सीजन शरीर के प्रत्येक अंग तक पहुचता है | इसी प्रकार CO₂ जो हमारे शरीर में ग्लूकोज के खंडित होकर ऊर्जा में बदलने पर बनती है |यह CO₂ रक्त के सपर्क में आने पर उसके प्लाजमा में घुल जाती है | यह CO₂ प्लाज़मा के द्वारा पूरे शरीर से पुन : रक्त से वायु में चली जाती है और अतः में नासद्रवारा से बाहर कर दी जाती है |

सही विकल्प है (घ) ये सभी

पाचन एंजाइम जटिल भोजन को सरल , सूक्ष्म तथा लाभदायक पदार्थ में बदल देता है | इस प्रकार से सरल पदार्थ छोटी आंत द्वारा अवशोषित कर लिए जाते है |

मानव फुफ्फुस छोटी -छोटी नलियों में बटा होती है | श्वसनी श्वसनिकाओ के बाद अत में कुपिकाए होती है जिनकी सरचना गुब्बरो के समान होती है | कुपिकाए ही गैसों के परिवहन को सरल बनाती है तथा एक विशाल क्षेत्र

हमारे आमाशय में हाईडरोक्लोरिक अम्ल उपस्थित होता है |यह अम्ल अमाशय में अम्लीय माध्यम का निर्माण करता है | इसी की मदद से एंजाइम अपना कार्य करता है | HCl अम्ल हमारे भोजन में उपस्थित रोगाणुओं को नष्ट कर देता है | HCl अम्ल आमाशय में भोजन को पचाने में सहायता करता है |

कूपिकाए अपने गुब्बारेनुमा आकार के कारण वायु के आदान – प्रदान को सरल बनाती है और सतही क्षेत्रफल की वृद्धि करती है | वायु भरने पर ये कूपिकाए फ़ैल जाती है तथा फुफ्फुस में परिवर्तित हो जाती है |

कूपिका :

1.  कूपिका शुद्ध व अशुद्ध वायु का वहन करती है |

2.  कूपिकाओ का आकार छोटा होता है |

3. कुपिका शरीर में रसायन CO₂ गैस के रूप में निकलती है |

वृक्काणु :

1.  वृक्काणु शुद्ध व अशुद्ध रुधिर वायु का वहन करती है |

2.  वृक्काणु लुपदार बड़े का आकार के होता है |

3.  वृक्काणु शरीर में नाइट्रोजन युक्त रसायन मूत्र के रूप में निकलती है |

मानव हृदय में रक्त दो बार संचरित होता है | इसके दोहरा परिसंचरण कहते है | इसी कारण ओक्सीजनित और विओक्सीजनित रूधिर एक – दुसरे से अलग रहता है | यदि ये बंटवारा न हो तो दोनों प्रकार के रक्त मिल जाएंगे और अंगो को पूर्ण रूप से ऑक्सीजन नहीं मिल पाएँग |

हीमोग्लोबिन हमारे शरीर में ऑक्सीजन का वहन करता है | लाल रक्त कण में यदि इनकी मात्रा कम हो जाती है तो शरीरं के अंगो को सुचारू रूप से ऑक्सीजन नहीं मिल पता है | जिससे भोजन का ऑक्सीकरण पूर्णतः नहीं हो पाता , जिससे ऊर्जा में भी कमी आती है और थकावट उत्पन्न होती है | इसकी कमी से व्यक्ति एनीमिया से पीड़ित हो जाता है|

जाइलम द्वारा पदार्थो का वहन :

1.  इसमें जल एवं खनिज लवण केवल उपरिमुखी दिशा में संवाहित होते है |

2.  इसमें जल तथा लवण का संवहन दाब तथा वाष्पोत्सर्जन कर्षण द्वारा होता है |

फ्लोएम द्वारा पदार्थो का वहन :

1.  इसमें भोजन , अमीनो अम्ल का संवहन दोनों दिशाओ में उपरिमुखी तथा अधोमुखी होता है |

2.  इसमें ATP ऊर्जा का प्रयोग होता है |