Parsons R L, Behringer F J, Medford J I
Department of Biology, Colorado State University, Fort Collins 80523-1878, USA.
Planta. 2000 Jun;211(1):34-42. doi: 10.1007/s004250000255.
Cell division and cell differentiation are key processes in shoot development. The Arabidopsis thaliana (L.) Heynh. SCHIZOID (SHZ) gene appears to influence cell differentiation and cell division in the shoot. The shz-2 mutant is notable in that distinct phenotypes develop, depending on the environment in which the plants are grown. When shz-2 mutants are grown in petri dishes, callus develops from the petiole and hypocotyl. In contrast, when the mutants are grown on soil, shoots appear externally stunted with malformed leaves. However, detailed examination of soil-grown mutants shows that the two phenotypes are related. Soil-grown mutants form adventitious meristems, produce a large amount of vascular tissues and have aberrant cell divisions in the meristem. Cells with abnormal cell-division patterns were found in the apical and vascular meristems, suggesting SHZ influences cell division. Development of callus in petri dishes, development of adventitious meristems and aberrations in leaves on soil suggest that SHZ influences cell differentiation. The distinct, but related phenotypes on soil and in petri dishes suggests that SHZ normally functions to regulate differentiation and/or cell division in a manner that is responsive to environmental conditions.
细胞分裂和细胞分化是茎发育过程中的关键过程。拟南芥（L.）Heynh. 的 SCHIZOID（SHZ）基因似乎影响茎中的细胞分化和细胞分裂。shz - 2突变体的显著之处在于，根据植物生长的环境会产生不同的表型。当shz - 2突变体在培养皿中生长时，愈伤组织从叶柄和下胚轴发育而来。相反，当突变体在土壤中生长时，茎外观发育不良，叶片畸形。然而，对在土壤中生长的突变体进行详细检查发现，这两种表型是相关的。在土壤中生长的突变体形成不定分生组织，产生大量维管组织，并且在分生组织中有异常的细胞分裂。在顶端分生组织和维管分生组织中发现了具有异常细胞分裂模式的细胞，这表明SHZ影响细胞分裂。在培养皿中愈伤组织的形成、不定分生组织的发育以及土壤中叶片的畸变表明SHZ影响细胞分化。在土壤中和培养皿中不同但相关的表型表明，SHZ通常以响应环境条件的方式发挥调节分化和/或细胞分裂的功能。
