Arthur M. Nonomura

The Path of Carbon in Photosynthesis. XXV. Plant and Algal Growth Responses to Glycopyranosides

ABSTRACT Substituted glycopyranosides were applied to various plant species as foliar and root treatments, with and without nutrient supplements, and growth was compared to untreated or nutrient controls. When formulated with specific fertilizers, particularly available nitrogen, methyl and ethyl glycopyranosides significantly enhanced the overall growth of vascular plants compared to controls provided with the same nutrients. In contrast, vascular plants treated with alkylglycopyranosides without nutrients showed growth equivalent to that of untreated controls. Nitrogen-supplemented alkylglycopyranosides provided as foliar applications of 100 mM, or as root treatments between 35 and 50 mM, consistently enhanced root and shoot productivity. In addition to the vascular plant species tested, the brown alga Laminaria saccharina exhibited significant growth enhancement over nutrient controls when treated with alkylglycopyranosides supplemented with nutrients, especially under low irradiance. Overall, these results indicate that growth of photosynthetic organisms is enhanced by exogenous alkylglycopyranosides supplemented with nitrogen and micronutrients, but not by alkylglycopyranosides alone.

THE PATH OF CARBON IN PHOTOSYNTHESIS. XXVI. UPTAKE AND TRANSPORT OF METHYLGLUCOPYRANOSIDE THROUGHOUT PLANTS

14Carbon methyl-β-D-glucopyranoside (14C-MeG) was applied to roots and shoots of Beta vulgaris L. and the label was tracked as it was transported and assimilated, primarily as a plant nutrient. Foliar application resulted in 6.7% of the 14C-MeG absorbed within 15 min of the solution drying into leaves. Roots in liquid medium with dissolved 14C-MeG absorbed approximately 97% of the 14C-label in 22 h. Whether fed in the light or dark, 40% of the 14C-MeG that was applied appeared in the cellulose fraction, incorporated completely intact. Rapid incorporation of 14C-MeG into the insoluble fraction with few 14C-labeled metabolites found in the soluble fraction were observed. In contrast to roots, a higher percentage of 14C-MeG was incorporated into starch and lipids of shoots.

THE PATH OF CARBON IN PHOTOSYNTHESIS. XXVII. SUGAR-CONJUGATED PLANT GROWTH REGULATORS ENHANCE GENERAL PRODUCTIVITY

We have found that applications of sugar-conjugated plant growth regulators (SPGRs) by exposures of roots or shoots to millimolar (mM) SPGRs are key to their uptake and transport for enhancement of vegetative productivity of the entire plant as compared to control populations. Initial surveys utilizing foliar applications of identically nutrient-supplemented 0.3 mM cytokinin glycosides, N6-benzyladenine glycosides, kinetin glycosides; and a 0.3 mM auxin glycoside, indoxyl-β-D-glucopyranoside (IG) resulted in significant shoot enhancements over controls. Foliar application of 0.3 mM kinetin glucoside resulted in significant root increase above the control. Foliar application of 3 mM to 6 mM IG resulted in enhanced root and shoot growths over controls. Similarly, increases of root and shoot yields over controls were observed as a result of foliar application of 3 mM indoxyl-β-D-glucuronide. Foliar application of 1 mM trans-zeatin-β-D-glucoside was particularly effective, resulting in significant enhancement of root and shoot growth with no phytotoxicity.

THE PATH OF CARBON IN PHOTOSYNTHESIS. XXXI. THE ROLE OF LECTINS

Radish (Raphanus sativus) and Swiss Chard (Beta vulgaris) seedlings, grown hydroponically, exhibited significantly greater increases in height and weight in medium containing α-mannoside supplemented with calcium and manganese salts, than in control treatments lacking one or more of those components. Furthermore, seeds sown on medium containing α-mannoside plus Ca2+and Mn2+showed accelerated germination. Calcium and manganese are necessary to maintain the protein conformation of mannose-binding lectins. In the presence of those cations, glycosides displace specific sugars bound to lectins, making them available to support plant growth.

Andrew A. Benson: personal recollections

Abstract Andrew A. Benson, one of the greatest and much loved scientists of our century, passed away on January 16, 2015; he was born on September 24, 1917. A grand celebration of his life was held on February 6, 2015, in California. Here, we present one of his photographs and key excerpts from what was said then, and soon thereafter.

THE PATH OF CARBON IN PHOTOSYNTHESIS. XXIX. GLASS MICROBEADS

Glass microbeads are introduced as convenient and applicable mechanical supports for hydroponics that can be released from roots to exhibit visually discernible responses. Moreover, glass microbeads refract light, effectively redistributing light toward the phylloplane. The smallest beads, <300 μm diameter, rose from neutral to ∼pH 9 in water and the rise was attributable the raw materials source, sodalime glass. The largest 700 μm diameter beads were relatively stable in buffered nutrients. Photography of unobstructed roots was aided by release of microbeads from ryegrass, coleus, corn, and narcissus. Propagation of ‘Ninsei’ was undertaken in containers constructed with inflow and drainage ports. Photodocumentation of responses to indoxylglucopyranoside exhibited consistent differences as compared to controls when cultured in glass microbeads; and further investigations into increased light intensity by refraction may lead to enhanced photosynthetic efficiency.

The paths of Andrew A. Benson: a radio-autobiography

Andrew A. Benson, one of the greatest biochemists of our time, is celebrated on his centennial by the authors with whom he interacted performing experiments or contemplating metabolic pathways in a wide range of biological kingdoms. He charted the chemical flow of energy in cells, tissues, organs, plants, animals, and ecosystems. Benson collaborated with hundreds of colleagues to examine the natural history of autotrophy, mixotrophy, and heterotrophy while elucidating metabolic pathways. We present here a biological perspective of his body of studies. Benson lived from September 24, 1917, to January 16, 2015. Out of over 1000 autoradiograms he produced in his life, he left a legacy of 50 labeled autoradiograms to the authors who tell the story of his life’s work that resulted in Benson’s Protocol (Nonomura et al., Photosynth Res 127:369–378, 2016) that has been applied, over the years, for the elucidation of major metabolic pathways by many scientists.