Beiträge zur Biologie der Pflanzen.

Bd. 2

Beiträge zur Biologie der Pflanzen.

Bd. 11

Beiträge zur Biologie der Pflanzen.

Bd. 12

Moderately High Temperatures Inhibit Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase (Rubisco) Activase-Mediated Activation of Rubisco

We tested the hypothesis that light activation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is inhibited by moderately elevated temperature through an effect on Rubisco activase. When cotton (Gossypium hirsutum L.) or wheat (Triticum aestivum L.) leaf tissue was exposed to increasing temperatures in the light, activation of Rubisco was inhibited above 35 and 30°C, respectively, and the relative inhibition was greater for wheat than for cotton. The temperature-induced inhibition of Rubisco activation was fully reversible at temperatures below 40°C. In contrast to activation state, total Rubisco activity was not affected by temperatures as high as 45°C. Nonphotochemical fluorescence quenching increased at temperatures that inhibited Rubisco activation, consistent with inhibition of Calvin cycle activity. Initial and maximal chlorophyll fluorescence were not significantly altered until temperatures exceeded 40°C. Thus, electron transport, as measured by Chl fluorescence, appeared to be more stable to moderately elevated temperatures than Rubisco activation. Western-blot analysis revealed the formation of high-molecular-weight aggregates of activase at temperatures above 40°C for both wheat and cotton when inhibition of Rubisco activation was irreversible. Physical perturbation of other soluble stromal enzymes, including Rubisco, phosphoribulokinase, and glutamine synthetase, was not detected at the elevated temperatures. Our evidence indicates that moderately elevated temperatures inhibit light activation of Rubisco via a direct effect on Rubisco activase.

Dynamic Precision Phenotyping Reveals Mechanism of Crop Tolerance to Root Herbivory

The western corn rootworm (WCR) is a major pest of maize that is well adapted to most crop management strategies. Breeding for tolerance is a promising alternative to combat WCR, but is currently constrained by a lack of physiological understanding and phenotyping tools. We developed dynamic precision phenotyping approaches using carbon-11 with positron emission tomography, root autoradiography and radiometabolite flux analysis to understand maize tolerance to WCR. Our results reveal that WCR attack induces specific patterns of lateral root growth which are associated with a shift in auxin biosynthesis from indole-3-pyruvic acid to indole-3-acetonitrile. WCR attack also increases transport of newly synthesized amino acids to the roots, including the accumulation of glutamine. Finally, the regrowth zones of WCR attacked roots show an increase in glutamine turnover which strongly correlates with the induction of indole-3-acetonitrile-dependent auxin biosynthesis. In summary, our findings identify local changes in the auxin flux network as a promising marker for induced WCR tolerance.

Biotransformation and chemical form of mercury in plants /

Bibliography: p. 7-9.

Annual report of the director /

Also issued as part of the institution's Year book.

Life histories of plants.

Mode of access: Internet.

[Reprints]

4 reprints of articles previously published in scientific journals.

Nouveaux élements de botanique et de physiologie végétale /

Mode of access: Internet.

Handbuch der Experimental-Physiologie der Pflanzen : Untersuchungen über die allgemeinenstein Lebensbedingungen der Pflanzen und die Functionen ihrer Organe /

Bibliografía a pie de página.

Die Natur der lebendigen Pflanze.

Vol. 2 has title: Die Fortpflanzung und Ernährung der Pflanzen.

Beitra ge zur allgemeinen Botanik /

At head of title: Pflanzenphysiologischen Institut der Universita t Berlin.

Soobshchenii︠a︡.

Issues for 1920 never published.

Wissenschaftlich-praktische untersuchungen auf dem gebiete des pflanzenbaues. Mittheilungen aus dem Landwirthschaftlichen laboratorium der K. K. Hochschule für bodencultur in Wien,

Mode of access: Internet.