Pollen grains can be stored for several years in liquid nitrogen having a temperature of (a) –120°C (b) –80°C (c) –196°C (d) –160°C

Pollen grains can be stored for several years in liquid
nitrogen having a temperature of
(a) –120°C (b) –80°C
(c) –196°C (d) –160°C
by

1 Answer

Answer :

(c) –196°C
by

Related questions

Pollen grains can be stored for several years in liquid nitrogen having a temperature of (1) –120°C (2) –80°C (3) –196°C (4) –160°C

Description : Pollen grains can be stored for several years in liquid nitrogen having a temperature of (1) –120°C (2) –80°C (3) –196°C (4) –160°C

Last Answer : (3) –196°C

Which one of the following statements is not true? (a) Pollen grains of many species cause severe allergies. (b) Stored pollen in liquid nitrogen can be used in the crop breeding programmes. (c) Tapetum helps in the dehiscence of anther. (d) Exine of pollen grains is made up of sporopollenin.

Description : Which one of the following statements is not true? (a) Pollen grains of many species cause severe allergies. (b) Stored pollen in liquid nitrogen can be used in the crop breeding programmes. (c) Tapetum helps in the dehiscence of anther. (d) Exine of pollen grains is made up of sporopollenin.

Last Answer : (c) Tapetum helps in the dehiscence of anther.

In gymnosperms, the pollen chamber represents (a) a cavity in the ovule in which pollen grains are stored after pollination (b) an opening in the megagametophyte through which the pollen tube approaches the egg(c) the microsporangium in which pollen grains develop (d) a cell in the pollen grain in which the sperms are formed.

Description : In gymnosperms, the pollen chamber represents (a) a cavity in the ovule in which pollen grains are stored after pollination (b) an opening in the megagametophyte through which the pollen tube approaches the ... pollen grains develop (d) a cell in the pollen grain in which the sperms are formed.

Last Answer : (c) the microsporangium in which pollen grains develop

At what temperature is gypsum heated to form Plaster of Paris?a) 90°C b) 100°C c) 110°C d) 120°C

Description : At what temperature is gypsum heated to form Plaster of Paris?a) 90°C b) 100°C c) 110°C d) 120°C

Last Answer : b) 100°C

Temperature and pressure in urea autoclave is (A) 120°C and 300 atm (B) 190°C and 200 atm (C) 400°C and 550 atm (D) 200°C and 10 atm

Description : Temperature and pressure in urea autoclave is (A) 120°C and 300 atm (B) 190°C and 200 atm (C) 400°C and 550 atm (D) 200°C and 10 atm

Last Answer : (B) 190°C and 200 atm

During the manufacture of sulphuric acid, the temperature of molten sulphur is not increased beyond 160°C, as (A) It is very corrosive at elevated temperature (B) Its viscosity is not reduced on further heating (hence pressure drop on pumping it, cannot be further reduced) (C) It decomposes on further increasing the temperature (D) None of these

Description : During the manufacture of sulphuric acid, the temperature of molten sulphur is not increased beyond 160°C, as (A) It is very corrosive at elevated temperature (B) Its viscosity is not reduced on ... be further reduced) (C) It decomposes on further increasing the temperature (D) None of these

Last Answer : (B) Its viscosity is not reduced on further heating (hence pressure drop on pumping it, cannot be further reduced)

A metal resistor has resistance of 10 ohm at 0°C and 11 ohms at 160°C, the temperature coefficient is

Last Answer : A metal resistor has resistance of 10 ohm at 0°C and 11 ohms at 160°C, the temperature coefficient is 0.000625 /°C.

When pollen grains are transferred to the stigma? -Biology

Description : When pollen grains are transferred to the stigma? -Biology

Last Answer : answer:

When pollen grains are transferred to the stigma? -Biology

Description : When pollen grains are transferred to the stigma? -Biology

Last Answer : answer:

What are pollen grains? -Biology

Description : What are pollen grains? -Biology

Last Answer : answer:

Where are pollen grains produced? -Biology

Description : Where are pollen grains produced? -Biology

Last Answer : answer:

What do pollen grains contain? -Biology

Description : What do pollen grains contain? -Biology

Last Answer : answer:

What are pollen grains? -Biology

Description : What are pollen grains? -Biology

Last Answer : answer:

What do pollen grains contain? -Biology

Description : What do pollen grains contain? -Biology

Last Answer : answer:

Where are pollen grains produced? -Biology

Description : Where are pollen grains produced? -Biology

Last Answer : answer:

Why were at least twenty pollen grains needed for each sugar concentration?

Description : Why were at least twenty pollen grains needed for each sugar concentration?

Last Answer : Anything less and the sample size would be too small for reliable data

How are pollen grains adapted to help plant pollinations?

Description : How are pollen grains adapted to help plant pollinations?

Last Answer : Some pollen grains have a spiky surface to help them sticky tothe bodies of insects.

What are the two ways in which pollen grains are scattered?

Description : What are the two ways in which pollen grains are scattered?

Last Answer : Pollen is scattered by the wind or by animals.

When pollen grains from flower of one plant transferred to receptive stigmas of flowers of another plant

Description : When pollen grains from flower of one plant transferred to receptive stigmas of flowers of another plant

Last Answer : Ans. Cross pollination/Allogamy

When pollen grains from an another falls on receptive stigma of the same flowers

Description : When pollen grains from an another falls on receptive stigma of the same flowers

Last Answer : Ans. Self pollination

Consider the following statements about pollination. 1. Transfer of pollen grains from the anther to ovules in the same flower or a different f lower is called pollination. 2. The pollination by wind is called anemophily. 3. Pollination is a prerequisite for seed and fruit development in all flowering plants. 4. Seeds may develop in some water ferns without pollination. Which of the above statement/s is/are correct? (a) 1 and 3 (b) 1, 2 and 4 (c) Only 2 (d) 1, 2, 3 and 4

Description : Consider the following statements about pollination. 1. Transfer of pollen grains from the anther to ovules in the same flower or a different f lower is called pollination. 2. The pollination by wind is called anemophily. 3. Pollination is a ... 1 and 3 (b) 1, 2 and 4 (c) Only 2 (d) 1, 2, 3 and 4

Last Answer : Ans:(c)

In dicots the pollen-grains possess : (1) two germ pores (2) three germ pores (3) four germ pores (4) one germ pore

Description : In dicots the pollen-grains possess : (1) two germ pores (2) three germ pores (3) four germ pores (4) one germ pore

Last Answer : (2) three germ pores Explanation: Pollen grains of monocots have one opening, while pollen grains of dicots have three openings. Pollengrains can be monocolpate (having one germ pore called germinal furrow e.g., monocots), bicolpate (2 germ pores) and tricolpate (3 germ pores e.g., dicots).

The floral part that receives pollen grains during pollination is - (1 ovary (2) style (3) stigma (4) ovules

Description : The floral part that receives pollen grains during pollination is - (1 ovary (2) style (3) stigma (4) ovules

Last Answer : (3) stigma Explanation: The stigma is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower. The stigma receives pollen at pollination and it is on the stigma that the pollen grain germinates. The style connects the stigma to the ovary.

The floral part that produces pollen grains is (1) Sepal (2) Petal (3) Anther (4) Ovary

Description : The floral part that produces pollen grains is (1) Sepal (2) Petal (3) Anther (4) Ovary

Last Answer : (3) Anther Explanation: The anther contains microsporangia. Each microsporangium contains pollen mother cells. These undergo meiosis, and produce pollen grains, which contain the male gametes (sperm). The pollen is released by the opening of the anther.

The floral part that produces pollen grains is - (1 ) Sepal (2) Petal (3) Anther (4) Ovary

Description : The floral part that produces pollen grains is - (1 ) Sepal (2) Petal (3) Anther (4) Ovary

Last Answer : (3) Anther Explanation: Anther is the apical portion of a stamen, which produces the microspores or pollen grains. An anther normally comprises four pollen sacs arranged in two groups or lobes joined by the connective tissue to the filament

The pollen grains of flowers pollinated by insects are : (1) smooth and dry (2) rough and sticky (3) rough and dry (4) large and, showy

Description : The pollen grains of flowers pollinated by insects are : (1) smooth and dry (2) rough and sticky (3) rough and dry (4) large and, showy

Last Answer : (2) rough and sticky Explanation: Pollen grains are large sticky and heavy, usually with rough surfaces so that they can readily cling onto the insects bodies. They are sticky so that pollen grains settling on them are not easily displaced.

Pollen grains in plants are produced in?

Description : Pollen grains in plants are produced in?

Last Answer : flower

The transfer of pollen grains from the an- ther to the stigma is called?

Description : The transfer of pollen grains from the an- ther to the stigma is called?

Last Answer : pollination

Which ones produce androgenic haploids in anther cultures? (a) Anther wall (b) Tapetal layer of anther wall (c) Connective tissue (d) Young pollen grains

Description : Which ones produce androgenic haploids in anther cultures? (a) Anther wall (b) Tapetal layer of anther wall (c) Connective tissue (d) Young pollen grains

Last Answer : (d) Young pollen grains

In tissue culture medium, the embryoids formed from pollen grains is due to (a) cellular totipotency (b) organogenesis (c) double fertilization (d) test tube culture.

Description : In tissue culture medium, the embryoids formed from pollen grains is due to (a) cellular totipotency (b) organogenesis (c) double fertilization (d) test tube culture.

Last Answer : (a) cellular totipotency

Which one of the following statements is wrong? (a) When pollen is shed at two-celled stage, double fertilisation does not take place. (b) Vegetative cell is larger than generative cell. (c) Pollen grains in some plants remain viable for months. (d) Intine is made up of cellulose and pectin.

Description : Which one of the following statements is wrong? (a) When pollen is shed at two-celled stage, double fertilisation does not take place. (b) Vegetative cell is larger than generative cell. (c) Pollen grains in some plants remain viable for months. (d) Intine is made up of cellulose and pectin.

Last Answer : (a) When pollen is shed at two-celled stage, double fertilisation does not take place.

In an angiosperm, how many microspore mother cells are required to produce 100 pollen grains? (a) 75 (b) 100 (c) 25 (d) 50

Description : In an angiosperm, how many microspore mother cells are required to produce 100 pollen grains? (a) 75 (b) 100 (c) 25 (d) 50

Last Answer : (c) 25

If there are 4 cells in anthers, what will be the number of pollen grains? (a) 16 (b) 12 (c) 8 (d) 4

Description : If there are 4 cells in anthers, what will be the number of pollen grains? (a) 16 (b) 12 (c) 8 (d) 4

Last Answer : a) 16

In grasses what happens in microspore mother cell for the formation of mature pollen grains? (a) One meiotic and two mitotic divisions (b) One meiotic and one mitotic divisions (c) One meiotic division (d) One mitotic division

Description : In grasses what happens in microspore mother cell for the formation of mature pollen grains? (a) One meiotic and two mitotic divisions (b) One meiotic and one mitotic divisions (c) One meiotic division (d) One mitotic division

Last Answer : (b) One meiotic and one mitotic divisions

Wind pollinated flowers are (a) small, brightly coloured, producing large number of pollen grains (b) small, producing large number of dry pollen grains (c) large producing abundant nectar and pollen (d) small, producing nectar and dry pollen

Description : Wind pollinated flowers are (a) small, brightly coloured, producing large number of pollen grains (b) small, producing large number of dry pollen grains (c) large producing abundant nectar and pollen (d) small, producing nectar and dry pollen

Last Answer : (b) small, producing large number of dry pollen grains

Transfer of pollen grains from the anther to the stigma of another flower of the same plant is called (a) xenogamy (b) geitonogamy (c) karyogamy (d) autogamy.

Description : Transfer of pollen grains from the anther to the stigma of another flower of the same plant is called (a) xenogamy (b) geitonogamy (c) karyogamy (d) autogamy.

Last Answer : (b) geitonogamy

Which one of the following statements is not true? (a) The flowers pollinated by flies and bats secrete foul odour to attract them. (b) Honey is made by bees by digesting pollen collected from flowers. (c) Pollen grains are rich in nutrients and they are used in the form of tablets and syrups. (d) Pollen grains of some plants cause severe allergies and bronchial afflictions in some people.

Description : Which one of the following statements is not true? (a) The flowers pollinated by flies and bats secrete foul odour to attract them. (b) Honey is made by bees by digesting pollen collected ... . (d) Pollen grains of some plants cause severe allergies and bronchial afflictions in some people.

Last Answer : (b) Honey is made by bees by digesting pollen collected from flowers.

Which of the following are the important floral rewards to the animal pollinators ? (a) Floral fragrance and calcium crystals (b) Protein pellicle and stigmatic exudates (c) Colour and large size of flower (d) Nectar and pollen grains

Description : Which of the following are the important floral rewards to the animal pollinators ? (a) Floral fragrance and calcium crystals (b) Protein pellicle and stigmatic exudates (c) Colour and large size of flower (d) Nectar and pollen grains

Last Answer : (d) Nectar and pollen grains

Which of the following statements is not correct? (a) Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil. (b) Some reptiles have also been reported as pollinators in some plant species. (c) Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style. (d) Insects that consume pollen or nectar without bringing about pollination are called pollen/ nectar robbers.

Description : Which of the following statements is not correct? (a) Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil. (b) ... Insects that consume pollen or nectar without bringing about pollination are called pollen/ nectar robbers.

Last Answer : (c) Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style.

Winged pollen grains are present in (a) mustard (b) Cycas (c) mango (d) Pinus

Description : Winged pollen grains are present in (a) mustard (b) Cycas (c) mango (d) Pinus

Last Answer : (d) Pinus.

The plant parts which consist of two generations- one within the other (1) pollen grains inside the anther (2) germinated pollen grain with two male gametes (3) seed inside the fruit (4) embryo sac inside the ovule (a) (1) only (b) (1), (2), and (3) (c) (3) and (4)

Description : The plant parts which consist of two generations- one within the other (1) pollen grains inside the anther (2) germinated pollen grain with two male gametes (3) seed inside the fruit (4) embryo sac inside the ovule (a) (1) only (b) (1), (2), and (3) (c) (3) and (4)

Last Answer : (d) (1) and (4).

Parthenocarpic tomato fruits can be producedby (a) treating the plants with phenylmercuric acetate (b) removing androecium of flowers before pollen grains are released (c) treating the plants with low concentrations of gibberellic acid and auxins (d) raising the plants from vernalized seeds

Description : Parthenocarpic tomato fruits can be producedby (a) treating the plants with phenylmercuric acetate (b) removing androecium of flowers before pollen grains are released (c) treating the plants with low concentrations of gibberellic acid and auxins (d) raising the plants from vernalized seeds

Last Answer : (c) treating the plants with low concentrations of gibberellic acid and auxins

Which of the following nutrient is involved in reproduction in plants and germination of pollen grains ? a. Boron b. Calcium c. Potassium d. Sulphur

Description : Which of the following nutrient is involved in reproduction in plants and germination of pollen grains ? a. Boron b. Calcium c. Potassium d. Sulphur

Last Answer : a. Boron

Winged pollen grains are present in (1) Mustard (2) Cycas (3) Mango (4) Pinus

Description : Winged pollen grains are present in (1) Mustard (2) Cycas (3) Mango (4) Pinus

Last Answer : (4) Pinus

The transfer of pollen grains from anther to stigma is called; a) Fertilization b) pollination c) Microsporogenesis d) Polyembryony

Description : The transfer of pollen grains from anther to stigma is called; a) Fertilization b) pollination c) Microsporogenesis d) Polyembryony

Last Answer : Ans. b) Pollination

Which layer of microsporangium provides nutrition to the developing pollen grains: a) Epidermis b) Endothecium c) Tapetum d) All

Description : Which layer of microsporangium provides nutrition to the developing pollen grains: a) Epidermis b) Endothecium c) Tapetum d) All

Last Answer : Ans : c) Tapetum

Which one of the following statements is wrong?a)Pollen grains in some plants remain viable for monthsb)Intine is made up of cellulose and pectinc)When pollen is shed at two-celled state, double fertilization does not take placed)Vegetative cell is larger than generative cell

Description : Which one of the following statements is wrong?a)Pollen grains in some plants remain viable for monthsb)Intine is made up of cellulose and pectinc)When pollen is shed at two-celled state, double fertilization does not take placed)Vegetative cell is larger than generative cell

Last Answer : c)When pollen is shed at two-celled state, double fertilization does not take place

Transfer of pollen grains from the anther to the stigma of another flower of the same plant is called:a) Autogamyb) Xenogamyc) Geitonogamyd) Karyogamy

Description : Transfer of pollen grains from the anther to the stigma of another flower of the same plant is called:a) Autogamyb) Xenogamyc) Geitonogamyd) Karyogamy

Last Answer : c) Geitonogamy

The process involving emasculation of the flower before anthesis and depositing pollen grains on the cut end of the ovary is called as

Description : The process involving emasculation of the flower before anthesis and depositing pollen grains on the cut end of the ovary is called as

Last Answer : The process involving emasculation of the flower before anthesis and depositing pollen grains on the cut end of the ovary is called as – Intra-ovarian pollination