The Comparative Boron Nutrition of Several Green and Blue‐Green Algae

Abstract

The boron requirements of filamentous and non‐filamentous species of green and blue‐green algae have been investigated. A primary feature of this study was the quantitative analysis of the cells for boron. This permitted expression of the degree of purification of the environment and the boron requirements of the organisms in terms of cell content. Three species of green algae were shown neither to require boron nor to absorb it in appreciable amounts. In contrast, three species of blue‐green algae readily absorbed boron and nitrogen fixing species showed a marked growth response to boron when nitrate was omitted from the culture medium. The response to boron was less with nitrate in the medium, probably due to increased contamination from the nitrate salt rather than an involvement of boron in the fixation process. The boron content of the deficient blue‐green algae was 1–2 μg/g, suggesting a requirement below dicot angiosperms and comparable to monocots. In agreement with other reports, the fungus Penicillium chrysogenum neither required nor absorbed boron.

Boron Requirement in Cyanobacteria

“…Since B was not sequestered by complexing with carbohydrates, and, with the evolution of xylem through which B was passively carried to the end of the transpiration stream, it acquired a regulatory role in plant metabolism (12,13). There is some evidence that B is not essential for nondinitrogen fixing forms of Cyanobacteria (8,14) or for the nonheterocystous, dinitrogen-fixing forms, Gloeothece sp. and Plectonema sp.…”

“…In Cyanobacteria, addition of B was reported to stimulate growth rates in the absence of combined nitrogen for Nostoc muscorum, Calothrix parietina, and Anabaena cylindrica (5,8). When nitrate was present in the medium, the addition of boron had only a small effect on the growth rate of these Cyanobacteria.…”

“…Lewin (10,11) and Smyth and Dugger (23,24) provided sound evidence that boron was required by marine and freshwater diatoms. However, other investigators (6,8,16) failed to demonstrate a requirement for boron in Chlorella and other green algae.…”

“…When nitrate was present in the medium, the addition of boron had only a small effect on the growth rate of these Cyanobacteria. Microcystis aeruginosa, which does not fix molecular nitrogen, showed no requirement although it absorbed boron in appreciable amounts (8). Gerloff (8) suggested that the smaller response to boron deficiency in cells grown with nitrate compared with cells grown with dinitrogen was due to boron contamination from the nitrate salt.…”

Stockage intracellulaire des nutriments chez l'algue verteChlorella sorokinianaShihira & Krauss

“…Depuis l'isolement de la première souche de Chlorelle par Beijerinck en 1890, une multitude de travaux sur les exigences nutritionnelles de ce groupe d'algues a vu le jour (Walker 1953, Krauss 1955, 1958, Eyster et al 1958, Bowen et al 1965, Gerloff 1968, O'Kelly 1968, McBridge et al 1971, Bruckner & Hofner 1977, Pistorius et al 1978, Nakajima et al 1979, Neilson & Larsson 1980, Joung & Akin 1983. Outre la source de carbone (CO2) et l'éner-gie lumineuse, de nombreux éléments minéraux indispensables à la croissance de Chlorella spp.…”