Chapter 38 - Angiosperm Reproduction and Biotechnology

Environmental signals

Environmental signals

________, such as temperature or illumination changes, are frequently required to break dormancy.

Stamens

________ produce anthers, which contain haploid microspores that mature into pollen grains bearing a male gametophyte.

Plant breeders

________ have genetically altered characteristics of a few hundred wild angiosperm species through artificial selection for over 10, 000 years, converting them into the crops we grow today.

Carpels

________ and stamens are sporophylls- reproduction- specialized modified leaves; sepals and petals are sterile modified leaves.

Pollination

________ is the placement of pollen on the stigma of a carpel, which occurs before fertilization.

GM

Genetically modified (________) plants have the potential to improve the quality and quantity of food available throughout the world, as well as play a growing role in biofuel production.

Hybridization

________ of various plant types and even species is frequent in nature and has been exploited by ancient and modern breeders to introduce new genes into crops.

Flowers

________ are fixed stems that stop growing after the bloom and fruit have developed.

Pollinators

________ are attracted by the petals.

stigma

The ________ is a sticky feature at the apex of the style that catches pollen.

meiosis

By ________, the diploid plant, the sporophyte, generates haploid spores.

seeds

The contained ________ are protected by the fruit, which assists in wind dispersal or the attraction of ________- dispersing animals.

Plants

________ may be cloned from single cells, which can then be genetically modified before being released into the wild.

Crops

________ are modified through breeding and genetic engineering.

petals

Sepals, ________, stamens, and carpels are the four floral organs.

double fertilization

Flowers, ________, and fruits are all essential components of the angiosperm life cycle.

Double fertilization

________ requires two sperm, which is a procedure in which one sperm fertilizes the egg, creating a zygote and, eventually, an embryo, while the other sperm does not.

angiosperm life cycle

The ________ is characterized by flowers, double fertilization, and fruits.

pollination

Following ________, the pollen tube releases two sperm into the female gametophyte.

Mitosis

________ divides these spores, resulting in multicellular gametophytes, the male and female haploid plants that generate gametes (sperm and eggs)

sexual reproduction

Flowers, which are generated by the sporophyte, are used for ________.

Angiosperm reproduction

________ is characterized by a generational switch between a multicellular diploid sporophyte generation and a multicellular haploid gametophyte generation.

Carpels

________ make up the first (innermost) whorl, stamens make up the second, petals make up the third, and sepals make up the fourth (outermost) whorl.

Plants

________ have evolved a variety of mechanisms to avoid self- fertilization, including male and female flowers on separate individuals, nonsynchronous production of male and female parts within a single flower, and self- incompatibility reactions in which pollen grains bearing an allele identical to one in the female are rejected.

Double fertilization

________ requires two sperm, which is a procedure in which one sperm fertilizes the egg, creating a zygote and, eventually, an embryo, while the other sperm does not.

plants

Flowering ________ reproduce sexually, asexually, or both sexually and asexually.

pollination

Following ________, the pollen tube releases two sperm into the female gametophyte.

Pollination

________ is the placement of pollen on the stigma of a carpel, which occurs before fertilization.