| 单词 | pollen tube |
| 例句 | Male gametes reach female gametophyte and the egg cell gamete though a pollen tube: an extension of a cell within the pollen grain. Fundamentals of Biology 2015-01-01T00:00:00Z Each pollen grain contains two cells: one generative cell that will divide into two sperm, and a second cell that will become the pollen tube cell. Concepts of Biology 2013-04-25T00:00:00Z When a pollen grain lands on the stigma, it grows a pollen tube. Miller & Levine Biology 2018-01-01T00:00:00Z When the bubbles popped, the pollen landed on the pistil, the female reproductive part, and the grains grew pollen tubes. Drone-delivered soap bubbles could help pollinate flowers 2020-06-17T04:00:00Z In addition, eH2O2 signals regulate the polarized growth of pollen tubes and root hairs6, and control the opening and closing of stomata3 — pores on the outer layer of the leaf formed by two guard cells. How plant cells sense the outside world through hydrogen peroxide 2020-02-18T05:00:00Z When a pollen grain reaches the stigma, a pollen tube extends from the grain, grows down the style, and enters through the micropyle: an opening in the integuments of the ovule. Fundamentals of Biology 2015-01-01T00:00:00Z The pollen tube grows from the pollen grain slowly, and the generative cell in the pollen grain divides into two sperm cells by mitosis. Concepts of Biology 2013-04-25T00:00:00Z The pollen tube grows into the style, eventually reaching the ovary and entering an ovule, resulting in double fertilization, where a diploid zygote and endosperm are produced. Miller & Levine Biology 2018-01-01T00:00:00Z In 2006, I entered an international photography contest in Germany and submitted an image of a pollen grain germinating, just at the point of releasing a pollen tube. Turning point: Martin Oeggerli 2012-07-04T21:50:44.007Z Most likely, “some sort of molecule is triggered that repels the other pollen tubes,” he said. Observatory: Fertilization in Flowers Marked by Expert Precision 2012-05-21T21:52:49Z When the pollen lands on a female scale, a pollen tube grows toward the female gametophyte, which consists of an ovule containing the megaspore. Fundamentals of Biology 2015-01-01T00:00:00Z Each pollen grain contains two cells: one generative cell that will divide into two sperm, and a second cell that will become the pollen tube cell. Concepts of Biology 2013-04-25T00:00:00Z If a pollen grain lands near an ovule, the grain splits open and begins to grow a pollen tube. Miller & Levine Biology 2018-01-01T00:00:00Z Among the possible advantages for the plant, he said, are faster growth of pollen tubes. Observatory: Yeast Makes Temperatures Rise, Too 2010-02-26T23:23:00Z In this remarkable statement he seems to anticipate in part the discoveries afterwards made as to pollen tubes, and more particularly the peculiar views promulgated by Schleiden. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3 "Borgia, Lucrezia" to "Bradford, John" An opening called a micropyle allows entry of the pollen tube from the base. Fundamentals of Biology 2015-01-01T00:00:00Z When a pollen grain reaches the stigma, a pollen tube extends from the grain, grows down the style, and enters through an opening in the integuments of the ovule. Concepts of Biology 2013-04-25T00:00:00Z Once the pollen tube reaches the female gametophyte, one sperm nucleus disintegrates; the other fertilizes the egg contained within the female gametophyte. Miller & Levine Biology 2018-01-01T00:00:00Z Each ovule, which is reached by a pollen tube, swells up and becomes a seed. Mendelism Third Edition These rapidly expand into "pollen tubes," or filaments, and, penetrating the long style, reach the egg-germs below. More Science From an Easy Chair It takes approximately one year for the pollen tube to grow and migrate towards the female gametophyte. Fundamentals of Biology 2015-01-01T00:00:00Z Inside the ovary are little bodies called the ovules that are moistened by a fluid that comes from this delicate pollen tube, and at once they begin to enlarge and eventually become the seeds. Ontario Teachers' Manuals: Nature Study Pollen was assumed to have germinated if the length of the pollen tube exceeded the diameter of the pollen grain. Northern Nut Growers Association Thirty-Fourth Annual Report 1943 The pollen tubes then penetrate the stigma, pass down the style, and eventually reach the ovules in the lower part of the pistil. Mendelism Third Edition Finally the pollen tube penetrates down to and through the open neck of the archegonium, until it comes in contact with the egg cell. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The pollen tube will be unable to form. Fundamentals of Biology 2015-01-01T00:00:00Z This embryo is the product of fertilization of a germinal vesicle by a pollen tube. Scientific American Supplement, No. 531, March 6, 1886 Germination was distinctly abnormal with short stubby pollen tubes, often with numerous nodular swellings. Northern Nut Growers Association Thirty-Fourth Annual Report 1943 Each pollen grain contains two cells: one generative cell that will divide into two sperm and a second cell that will become the pollen tube cell. Fundamentals of Biology 2015-01-01T00:00:00Z Fʺ, pollen spores germinating upon the stigma, × 300. pt. pollen tube. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The pollen tube will form but will not be guided toward the egg. Fundamentals of Biology 2015-01-01T00:00:00Z When the pollen lands on a female scale, a pollen tube grows toward the female gametophyte, which consists of an ovule containing the megaspore. Fundamentals of Biology 2015-01-01T00:00:00Z In general the pollen tube grew up into the air away from the surface of the agar, rather than down into it or parallel with the surface as in normal germination. Northern Nut Growers Association Thirty-Fourth Annual Report 1943 The generative cell is contained within the larger pollen tube cell. Fundamentals of Biology 2015-01-01T00:00:00Z This opening is called the “micropyle,” and allows the pollen tube to enter. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses Pollination is defined as the initiation of pollen tube growth. Fundamentals of Biology 2015-01-01T00:00:00Z Upon germination, the tube cell forms the pollen tube through which the generative cell migrates to enter the ovary. Fundamentals of Biology 2015-01-01T00:00:00Z One is called the generative nucleus, and the other is called the pollen tube nucleus. Fundamentals of Biology 2015-01-01T00:00:00Z The mature pollen grain is composed of two cells: the pollen tube cell and the generative cell, which is inside the tube cell. Fundamentals of Biology 2015-01-01T00:00:00Z By carefully opening the ovary and slightly crushing it in a drop of water, the pollen tube may sometimes be seen growing along the stalk of the ovule until it reaches and enters the micropyle. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The pollen tube develops slowly, and the generative cell in the pollen grain divides into two haploid sperm cells by mitosis. Fundamentals of Biology 2015-01-01T00:00:00Z The synergids help guide the pollen tube for successful fertilization, after which they disintegrate. Fundamentals of Biology 2015-01-01T00:00:00Z The micropyle allows the pollen tube to enter the female gametophyte for fertilization. Fundamentals of Biology 2015-01-01T00:00:00Z The integument contains an opening called the micropyle, through which the pollen tube enters the embryo sac. Fundamentals of Biology 2015-01-01T00:00:00Z Mature pollen grains contain two cells: a generative cell and a pollen tube cell. Fundamentals of Biology 2015-01-01T00:00:00Z |
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