PLANT PHYSIOLOGY

NANO REVIEW Open AccessCellulose fibres, nanofibrils and microfibrils: Themorphological sequence of MFC componentsfrom a plant physiology and fibre technologypoint of viewGary Chinga-CarrascoAbstractDuring the last decade, major efforts have been made to devel op adequate and commercia[r]

pp. 12–35.Finkelstein, A. (1987) Water Movement through Lipid Bilayers, Pores,and Plasma Membranes: Theory and Reality. Wiley, New York.Friedman, M. H. (1986) Principles and Models of Biological Transport.Springer Verlag, Berlin.Hsiao, T. C. (1979) Plant responses to water deficits, efficienc[r]

Stress Physiology25ChapterIN BOTH NATURAL AND AGRICULTURAL CONDITIONS, plants arefrequently exposed to environmental stresses. Some environmental fac-tors, such as air temperature, can become stressful in just a few minutes;others, such as soil water content, may take days to weeks, and facto[r]

). This specific race synthesizes a compound(HmT-toxin) that specifically interacts with the URF13 pro-tein to produce pores in the inner mitochondrial membrane,with the result that selective permeability is lost.The interaction between HmT-toxin and URF13 madeBipolaris maydis race T a particularly[r]

NNNNFerrochelataseFIGURE 12.17 The ferrochelatase reaction. The enzyme ferrochelatase cat-alyzes the insertion of iron into the porphyrin ring to form a coordinationcomplex. See Figure 7.37 for illustration of the biosynthesis of the porphyrinring. Assimilation of Mineral Nutrients 277where A repres[r]

isms measure time in general. This topic is known aschronobiology, or the study of biological clocks. The best-understood biological clock is the circadian rhythm.CIRCADIAN RHYTHMS:THE CLOCK WITHINOrganisms are normally subjected to daily cycles of lightand darkness, and both plants and animals ofte[r]

The preceding discussion of the energetic and elec-trical consequences of ion translocation illustrates apoint that must be clearly understood—namely, that anelectric potential across a membrane may arise by twodistinct mechanisms. The first mechanism, illustrated inFigure 2.4, is the diffusion of c[r]

indefinitely in a simple nutrient medium containing onlysucrose, mineral salts, and a few vitamins, with no addedhormones (White 1934).In contrast to roots, isolated stem tissues exhibit very lit-tle growth in culture without added hormones in themedium. Even if auxin is added, only limited growth m[r]

FIGURE 22.8 Reorientation of microtubules from transverse tovertical in pea stem epidermis cells in response to wounding. Aliving epidermal cell was microinjected with rhodamine-conju-gated tubulin, which incorporates into the plant microtubules.A time series of approximately 6-minute interva[r]

Went’s studies with agar blocks demonstrated unequivo-cally that the growth-promoting “influence” diffusing fromthe coleoptile tip was a chemical substance. The fact that itwas produced at one location and transported in minuteamounts to its site of action qualified it as an authenticplant hormone.I[r]

by the Nernst equation. The Nernst equation shows that atequilibrium the difference in concentration of an ionbetween two compartments is balanced by the voltage dif-ference between the compartments. That voltage difference,or membrane potential, is seen in all living cells because ofthe asymmetric[r]

main transport pathway of water, such embolisms wouldcause the dehydration and death of the leaves.54 Chapter 4Plants Minimize the Consequences of XylemCavitationThe impact of xylem cavitation on the plant is minimizedby several means. Because the tracheary elements in thexylem are interconne[r]

reported for any hormone in response to an environmen-tal signal. Redistribution or biosynthesis of ABA is veryeffective in causing stomatal closure, and its accumulationin stressed leaves plays an important role in the reductionof water loss by transpiration under water stress condi-tions (Figure 2[r]

responses, allowing the plant to sense the presence of lightand its direction. This section describes the major mor-phological, physiological, and biochemical changes associ-ated with typical blue-light responses.Blue Light Stimulates Asymmetric Growth andBendingDirectional growth toward (or[r]

by blue light and red light, which are strongly absorbed bychlorophyll. Today, action spectra can be measured inroom-sized spectrographs in which a huge monochroma-tor bathes the experimental samples in monochromaticlight. But the principle of the experiment is the same as thatof Engelmann’s experim[r]

basic mechanisms of signal transduction in animals,emphasizing pathways that may have some parallel inplants. However, keep in mind that plant signal trans-duction pathways may differ in significant ways fromthose of animals. To illustrate this point, we end thechapter with an overview of som[r]

leaves have some contrasting characteristics:• Shade leaves have more total chlorophyll per reactioncenter, have a higher ratio of chlorophyll b to chloro-phyll a, and are usually thinner than sun leaves.• Sun leaves have more rubisco, and a larger pool ofxanthophyll cycle components than shade leav[r]

ure 20.5). The use of bioassays, however, has declined withthe development of highly sensitive physical techniquesthat allow precise identification and quantification of spe-cific gibberellins from small amounts of tissue.High-performance liquid chromatography (HPLC) ofplant extracts, followed by th[r]

seedling uses primarily stored seed reserves for etiolated growth. How-ever, seed plants, including grasses, don’t store enough energy to sus-tain growth indefinitely. They require light energy not only to fuel pho-tosynthesis, but to initiate the developmental switch from dark to lightgrowth. Photo[r]

FIGURE 13.25 Many modes of antipathogen defense are induced by infection.Fragments of pathogen molecules called elicitors initiate a complex signaling path-way leading to the activation of defensive responses. Some bacterial protein elici-tors are injected directly into the cell, where they interact[r]