What are the three primary stages of embryogenesis? >>>Globular, Heart, Torpedo Radicle emergence involves cell growth and rupture of the tissues surrounding the embryo, but typically does not involve ___________. >>>cellular division The corpus of the apical meristem is divided into three zones. What are they? >>>central zone, peripheral zone, and rib meristem Biennial Growth >>>The plant grows vegetatively the first year, initiates flowers the second year before flowering, setting seed, and dying the second year. Determinate growth >>>When a shoot reaches a predetermined size the plant ceases to get larger. Annual growth >>>The plants grow and reach maturity producing flowers and seeds in one growing season. perennial growth >>>The cycle of growth and flowering is repeated year after year with the plant surviving the winter by storage organs or with perenating buds. Indeterminate growth >>>There is no set endpoint for plant size. Leaves or leaf primordia are important to stem elongation because they are an important source of ____________________. >>>auxins Growth in plants that exhibit a continuous growth pattern is typically regulated by _________ and __________. >>>season; temperature The two most important environmental factors regulating bud dormancy are >>>temperature and light Juvenility can be defined as >>>The initial period of plant growth when apical meristems will not respond to internal or external cues to initiate flowering. The rise in mitotic activity precedes the increase DNA synthesis in the central zone during transition to a reproductive meristem because ______ >>>there are a number of cells in the cell cycle just following DNA synthesis waiting to divide. Phytochrome Far Red >>>inhibits stem elongation Phytochrome Far Red to Phytochrome Red >>> Phytochrome Red >>>promotes stem elongation Phytochrome Red to Phytochrome Far Red >>> Fruit are the structural entities resulting from the development of tissues supporting the _______________. >>> Plants detect their proximity to neighboring plants by measuring ... >>> Hydrotropism >>>water Gravitropism >>>gravity Phototropism >>>light Thigmotropism >>>touch Monocot embryogenesis differs from Dicot embryogenesis in that >>>there is no heart stage in monocots because they have only one cotyledon. The concept exists that nearly all plant cells are totipotent. What does this mean? >>>All plant cells with a functional nucleus are capable of giving rise to a whole plant. Seeds that desiccate and become quiescent are known as ________ seed while those that hydrated at the time of seed shed and are unable to withstand desiccation are known as ______________ seed. >>>orthodox; unorthodox What is the first general phase of germination? >>>Emergence of the radicle. Seeds that have a specific requirement for light for germination are referred to as photoblastic seeds. These seeds require a brief exposure to red light while imbibed. What is the photoreceptor involved in this response? >>>phytochrome In the vegetative state, the levels of RNA are lower in the central zone cells than surrounding cells. Synthesis of RNA in this region is reported to be less active than in the peripheral zone because _______________. >>>these cells are relatively inactive and divide infrequently in the vegetative state. A leaf primordia differs from primordia leading to branches in that a leaf has a determinate growth pattern. What does this mean? >>>The leaf grows to a genetically and environmentally predetermined size and stops enlarging. A leaf is a complex structure with elaborate structural specialization. Which of the following is not one of the leaf's special structures? >>>Lenticels which allow for gas and water exchange in the plant. The first suggestion of leaf initiation is a swelling of the apical flank and involves at least _____ layers of the mersitem. >>>three Cells in the surface layer divide mainly ______________ during leaf initiation. >>>anticlinally The second phase of shoot growth is the ____________. >>>the elongation of the internodes. In many grasses, growth continues over an extended period of time. Even upon removal of the tops of the grass, we have to mow the lawn again and again and again. This is due to the presence of an _________ in grasses. >>>intercalary meristem What evidence exists for floral organs being a modification or further elaboration of a leaf? >>>if floral initiation is interrupted, floral parts revert to leaves. While a vegetative apex is normally a low dome with conspicuous zonation, the reproductive meristem typically has a high dome with an increase in mitotic activity in the ________________. >>>central zone Bolting is a response in rosetting plants where after receiving an environmental signal (usually photoperiod) the internodes undergo rapid elongation. ___________ has been implicated as one of the controlling factors in this rapid growth. >>>gibberellins Blue light >>>inhibits stem elongation Red light >>>inhibits stem elongation Far red light >>>promotes stem elongation Phytochrome far red >>>inhibits stem elongation Phytochrome red >>>promotes stem elongation End day with far red light >>>Maintains apical dominance Apply gibberellins. >>>Maintains apical dominance Mechanically pinch. >>>Breaks apical dominance (promotes branching) Space plants close together. >>>Maintains apical dominance Apply cytokinins to axillary buds >>>Breaks apical dominance (promotes branching) Space plants further apart. >>>Breaks apical dominance (promotes branching)