chapter 29

Question 1

what are the three minerals macronutrients are found in greatest amounts in most plant fertilizers

Answer 1

nitrogen, phosphorus & potassium

Question 2

what type of soil particle holds the most water, what type holds the least water

Answer 2

sand –» holds least water

clay –» holds most water

Question 3

what is the best soil pH for most plants

Answer 3

6.0-7.5pH

Question 4

why is organic matter (humus) better as a fertilizer than inorganic (commercial) fertilizers

Answer 4

–»soaks up water & releases it as needed

–»helps to keep soil loose

–»organic mulch on top of soil acts as a sunscreen & as a reservoir of nutrients which are released slowly –thus organic matter is better than commercial fertilizer because organic matter provides soil conditioning and slow release of minerals prevents fertilizer burn

Question 5

what is the most important factor involved in the ascent of water and minerals in tall plants

Answer 5

root pressure

Question 6

what are the main functions of the five major plant hormones

Answer 6

–»auxin—promote meristematic growth and cell elongation prevent leaves, flowers and fruits from falling off prematurely

–»cytokinins—stimulate cell division, inhibit aging of leaves; interact with auxin to produce the total growth patterns of the plant

–»gibberellins—promote stem elongation; stimulate leaf and flower growth

–»abscisic acid –inhibition growth; promotes dormancy in shoots and seeds; promotes closing of stomata during water stress

–»ethylene— fruit ripening; counteracts some of the effects of auxin; promotes dropping of leaves, flowers and fruits