Learning Objective Some plant parts, such as stems and roots, continue to grow throughout a plant’s life: a phenomenon called indeterminate growth. Other plant parts, such as leaves and flowers, exhibit determinate growth, which ceases when a plant part reaches a…
Learning Objectives Many mature seeds enter a period of inactivity, or extremely low metabolic activity: a process known as dormancy, which may last for months, years or even centuries. Dormancy helps keep seeds viable during unfavorable conditions. Germination occurs when the embryo, which…
Learning Objectives Eudicot Seeds The seed is protected by a seed coat that is formed from the integument of the ovule (Figure ). The seed coat is further divided into an outer coat known as the testa and inner coat known as the tegmen. The hilum is a…
Learning Objective Define and locate the two apical meristems and the three primary meristems. Meristems are centers of cell division and growth. In animals, totipotent stem cells, which can differentiate into any tissue type are only found early in development; however, plants contains…
Learning Objectives The Seed Plants chapter discussed the fertilization of the egg within the ovule. The zygote ultimately divides to produce the mature embryo, the ovule develops into a seed, and the ovary that contained one or more ovules develops into a…
Development is the process by which an organism changes over its life. In angiosperms, development after sperm from the pollen tube fertilizes the egg in the ovule, forming the diploid zygote. Through cell division and differentiation, the zygote forms a mature embryo,…
Water and minerals move through the xylem, and sugars move through the phloem. Water potential and transpiration influence how water is transported through the xylem in plants as described by the cohesion-tension theory. Water potential (Ψ) is a measure of the difference in…
Learning Objectives Plants need an energy source to grow. In seeds and bulbs, food is stored in polymers (such as starch) that are converted by metabolic processes into sucrose for newly developing plants. Once green shoots and leaves are growing,…
Learning Objectives Most plants secure the water and minerals they need from their roots. Water moves from the soil to the roots, stems, and ultimately the leaves, where transpiration occurs. The roots absorb enough water to compensate for water lost…
Learning Objectives In 1895, the Irish plant physiologists H. H. Dixon and J. Joly proposed that water is pulled up the plant by tension (negative pressure) from above. As we have seen, water is continually being lost from leaves by transpiration. Dixon…