Botany · Ch 9 — Plant Breeding
Rhizobium
Rhizobium
Rhizobium bio-fertilizer culture consists of preparations containing Rhizobium bacteria, which live symbiotically inside root nodules that form on the roots of leguminous plants (Figure 9.4). Within these nodules, the bacteria convert atmospheric nitrogen gas into a form the plant can use — a process called biological nitrogen fixation. When Rhizobium inoculant is applied to soil or seed, the bacteria multiply enormously, into the billions, and fix atmospheric nitrogen directly in the root zone, reducing the crop's dependence on nitrogen fertilizer. Rhizobium is particularly well suited to paddy (rice) fields, where its use has been shown to rais …
What this figure shows. Two-part figure: (a) a photograph or diagram of a legume root system showing multiple rounded root nodules formed along its length where Rhizobium bacteria have colonised the root; (b) a cross-sectional (C.S.) diagram of a single root nodule showing its internal tissue layers, including the central zone packed with nitrogen-fixing bacteroids housed inside plant cells, illustrating how the symbiotic bacteria are physically contained wi …