The circadian clock regulates diverse aspects of plant growth and development and promotes plant fitness. Molecular identification of clock components, primarily in Arabidopsis, has led to recent rapid progress in our understanding of the clock mechanism in higher plants. Using mathematical modeling and experimental approaches, workers in the field have developed a model of the clock that incor...

A survey has been made of the occurrence and distribution of three enzymes which metabolize cyanide in a variety of higher plants including both cyanogenic and non-cyanogenic species. The enzymes investigated were beta-cyanoalanine synthase, rhodanese and formamide hydrolyase. beta-Cyanoalanine synthase was found to be present in every higher plant tested whereas rhodanese was found to occur fa...

The pattern of protein synthesis changes rapidly and dramatically when the growth temperature of soybean seedling tissue is increased from 28 degrees C (normal) to about 40 degrees C (heat shock). The synthesis of normal proteins is greatly decreased and a new set of proteins, "heat shock proteins," is induced. The heat shock proteins of soybean consist of 10 new bands on one-dimensional NaDodS...

The sporophytic generation of higher plants is initiated with the double fertilization event that results in the formation of a single-celled zygote and a progenitor cell of the endosperm. Embryogenesis describes the subsequent period of development, during which the zygote undergoes a complex series of morphological and cellular changes resulting in the formation of a developmentally arrested ...

The plastid genome of higher plants is an attractive target for engineering because it provides readily obtainable high protein levels, the feasibility of expressing multiple proteins from polycistronic mRNAs and gene containment through the lack of pollen transmission. A chloroplast-based expression system that is suitable for the commercial production of recombinant proteins in tobacco leaves...

Silicon (Si) accumulation differs greatly between plant species because of differences in Si uptake by the roots. Recently, a gene encoding a Si uptake transporter in rice, a typical Si-accumulating plant, was isolated. The beneficial effects of Si are mainly associated with its high deposition in plant tissues, enhancing their strength and rigidity. However, Si might play an active role in enh...

Nickel was established as an essential micronutrient for the growth of temperate cereal crops. Grain from barley (Hordeum vulgare L. cv ;Onda'; containing 40 to 80 nanograms of Ni per gram dry weight) grown in solution culture with negligible Ni concentrations (< 30 nanograms of Ni per liter) exhibited greatly reduced germination rates (i.e. 50% less than grain from Ni-adequate plants) and seed...

1. [2-(14)C]Mevalonate was incorporated into squalene and the major phytosterols of pea and maize leaves; it was also incorporated into compounds belonging to the 4,4-dimethyl and 4alpha-methyl steroid groups and which may be possible phytosterol intermediates. 2. l-[Me-(14)C]Methionine was incorporated into the major sterols and also into the 4,4-dimethyl and 4alpha-methyl steroid groups. No r...

The synthesis of glutamine has been studied extensively with enzyme preparations from animal tissues and from bacteria (1, 2, 3, 9, 10). These studies have shown that in such organisms, glutamine may be formed directly from glutamic acid and ammonia, the energy for the synthesis being supplied as adenosine triphosphate (ATP). Little is known, however, of the occurrence or characteristics of sim...

Most plant mRNAs are synthesized as precursors containing one or more intervening sequences (introns) that are removed during the process of splicing. The basic mechanism of spliceosome assembly and intron excision is similar in all eukaryotes. However, the recognition of introns in plants has some unique features, which distinguishes it from the reactions in vertebrates and yeast. Recent progr...