Ligrone R, Renzaglia K S
Universita di Napoli, Dipartimento di Biologia vegetale, via Foria 223, 1-80139 Napoli, Italy.
East Tennessee State University, Department of Biological Sciences, Johnson City, TN 37614, USA.
New Phytol. 1990 Mar;114(3):497-505. doi: 10.1111/j.1469-8137.1990.tb00417.x.
The placenta of the anthocerote, Dendroceros tubercularis Hatt., consists of long and branched haustorial cells, that arise from the foot and gametophyte transfer cells. Both cell types contain electron-dense vacuolar deposits that were digested by pronase and therefore are assumed to be protein. These deposits were negative to the PATAg test for carbohydrates. Protein bodies were also found in the parenchyma cells of the foot and younger meristematic cells at the base of the capsule. Vacuolar deposits of osmiophilic material in the gametophyte cells external to the placenta were stained non-specifically with PATAg method and were not affected by pronase. The haustorial cells have pleomorphic plastids lacking starch and a thylakoid system, whereas the transfer cells have well developed chloroplasts. No pronase-sensitive material was detected in the apo plastic space separating gametophyte and sporophyte cells. These results suggest that protein is synthesized in the haustorial cells, perhaps from precursors provided by transfer cells, and is then transferred, via plasmodesmata, to the parenchyma cells of the foot and eventually to the cells of the growing capsule.
角苔纲植物瘤枝树角苔（Dendroceros tubercularis Hatt.）的胎盘由长而分支的吸器细胞组成，这些细胞源自基部和配子体传递细胞。这两种细胞类型都含有电子致密的液泡沉积物，这些沉积物能被链霉蛋白酶消化，因此被认为是蛋白质。这些沉积物对碳水化合物的PATAg测试呈阴性。在基部的薄壁细胞和较年轻的分生组织细胞中也发现了蛋白体。胎盘中配子体细胞中嗜锇物质的液泡沉积物用PATAg方法进行非特异性染色，且不受链霉蛋白酶影响。吸器细胞具有多形质体，缺乏淀粉和类囊体系统，而传递细胞具有发育良好的叶绿体。在分隔配子体和孢子体细胞的质外体空间中未检测到对链霉蛋白酶敏感的物质。这些结果表明，蛋白质在吸器细胞中合成，可能来自传递细胞提供的前体，然后通过胞间连丝转移到基部的薄壁细胞，最终转移到生长中的蒴果细胞。
