The evolution of photosynthesis and, at a later point, the emergence of land plants resulted in substantial changes in the composition of Earth’s atmosphere. Plant colonization of the land in the early Paleozoic (more than 450 million years ago [mya]) was followed by a rapid drop in atmospheric [CO2], while at the same time atmospheric […]
During leaf growth and development, chloroplast numbers increase to maximize photosynthetic capacity. In mesophyll cells, chloroplast division takes place primarily during cell expansion and increases plastid numbers from; 10 to 20 in leaf primordia to; 100 or more in mature mesophyll cells. Chloroplasts divide in the middle, producing populations of organelles that are generally similar […]
Simple plant cell morphologies, such as cylindrical shoot cells, are determined by the extensibility pattern of the primary cell wall, which is thought to be largely dominated by cellulose microfibrils, but the mechanism leading to more complex shapes, such as the brick-shaped or jigsaw-like patterns in the epidermal pavement cells of many eudicot leaves, is […]
Carrot (Daucus carota ssp. sativus) are classified into two groups: the carotene group (variety sativus) and the anthocyanin group (variety atrorubens). Carotene group members, also known as nonpurple carrots, accumulate massive amounts of carotenoids in their roots. Anthocyanin group members, also known as purple carrots, accumulate high levels of anthocyanins in their roots. Anthocyanins are […]
The circadian clock of plants coordinates many molecular, physiological and metabolic processes to optimize the plant’s health and survival in an ever-changing environment. The core circadian clock component TIMING OF CAB EXPRESSION1 (TOC1) integrates environmental stress responses in plants through its effects on abscisic acid signaling and growth suppression. The interaction of TOC1 with PHYTOCHROME […]
Lignin is a complex polymer deposited in plant cell walls that provides mechanical support and facilitates the transport of water and solutes through the vascular system, and aids in plant defense. Lignin waterproofs plant cells by providing a hydrophobic environment by chemical bonding with cellulose and hemicellulose. This lignin-polysaccharide matrix underlies the recalcitrance that limits […]
The phytohormone auxin plays critical roles in various plant developmental programs by controlling cell expansion and polarity, as well as organ patterning. Auxin action relies on polar transport through different plant tissues. Auxin transport inhibitors are important tools for understanding auxin-dependent plant development. One mode of auxin transport inhibition involves actin dynamics. A major role […]
Plasmodesmata are membranous pores that span the plant cell wall creating both cytoplasmic and membrane continuums between cells. By interconnecting most cells throughout the entire plant body, plasmodesmata form a symplastic network that supports and controls the movement of molecules from cell to cell, within a given tissue or organ. By regulating intercellular communication, plasmodesmata […]
The land invasion by plants more than 500 million years ago was facilitated by the formation of mutualistic symbioses with fungi, through which the earliest plants gained access to mineral nutrients in exchange for photosynthetically fixed carbon (C). It was long hypothesized that this ancient mycorrhiza-like symbiosis was closely related to, and subsequently evolved into, […]