Tang Caixian, Robson A D, Dilworth M J, Kuo J
Soil Science and Plant Nutrition, School of Agriculture.
School of Biological and Environmental Sciences, Murdoch University, Murdoch, WA 6150, Australia.
New Phytol. 1992 Jul;121(3):457-467. doi: 10.1111/j.1469-8137.1992.tb02946.x.
Lupins (Lupinus angustifolius L. ev. Yandee), grown in solution culture, have been used to study the sites and process of infection by Bradyrhizobium sp. (Lupinus) and the impairment of nodulation by iron deficiency. Infection leading to nodulation occurred in an area of epidermal cells either lacking root hairs or with very young root hairs at the time of inoculation. Cells aged 13 h or over appeared not to be infected. Infection was initiated in the outer cortex. Rare, short infection threads were evident on day 4 after inoculation, 2 d after the initial division of cortical cells resulting from the bradyrhizobial inoculation. Bacteria had been released into the cytoplasm of cortical cells within 5 d after inoculation. Bacteroids multiplied in the cytoplasm, segregated passively and spread in the infection zones by repeated division of the invaded cells. Under iron deficiency, initial cell division occurred in the outer cortex of host roots, as in iron-sufficient plants after inoculation. Iron deficiency then limited further division of cortical cells. Only a few surviving infection sites developed nodules with normal structure but development was much slower than in iron-sufficient plants.
在溶液培养中生长的羽扇豆（窄叶羽扇豆Lupinus angustifolius L.品种Yandee）已被用于研究慢生根瘤菌（羽扇豆）的感染部位和过程以及缺铁对结瘤的影响。导致结瘤的感染发生在接种时缺乏根毛或有非常幼嫩根毛的表皮细胞区域。13小时及以上的细胞似乎未被感染。感染始于外皮层。接种后第4天，即慢生根瘤菌接种导致皮层细胞最初分裂2天后，可见罕见的短感染线。接种后5天内细菌已释放到皮层细胞的细胞质中。类菌体在细胞质中繁殖，被动分离并通过被入侵细胞的反复分裂在感染区扩散。在缺铁条件下，宿主根的外皮层会发生最初的细胞分裂，就像接种后铁充足的植物一样。然后缺铁限制了皮层细胞的进一步分裂。只有少数存活的感染部位形成了结构正常的根瘤，但发育比铁充足的植物慢得多。
