Comparison of Cadmium Effect on Willow and Poplar in Response to Different Cultivation Conditions

Salix alba L. and Populus×euroamericana cv. Robusta cuttings were grown in 10 μM Cd(NO₃)₂ (direct treatment) or in Knop solution and afterwards in Cd(NO₃)₂ (indirect treatment). Cd impact on rooting of directly treated plants and its impact on normally formed roots and shoots of indirectly treated plants were studied. The cumulative length, number and biomass of willow roots, pigment and starch contents, leaf net photosynthetic rate and dry mass/leaf area ratio of willow leaves were positively influenced by indirect treatment. However, indirectly treated poplars were more sensitive to Cd than directly treated ones. Indirect treatment lowered root Cd uptake in willow, Cd accumulation in cuttings of both species and Cd accumulation in poplar shoots. Cd-caused structural changes were similar in both species and in both treatments. Root apices, rhizodermis and cortex were the most seriously damaged root parts. In directly treated willow, the structure of central cylinder (0.5 – 1 cm from apex) remained unchanged in contrast to indirectly treated plants. Formation of cambium close to the apex indicated shortening of root elongation zone of indirectly treated plants. Directly Cd-treated poplar roots exhibited unusual defence activity of root apical meristem and accumulation of darkly stained material around central cylinder. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ultrastructural and cytochemical studies on nucleolus-like bodies in early postimplantation rat embryos

Summary This study investigates the role of the developing diencephalic floor or mesenchymal tissue in the differentiation of ACTH-producing cells.The adenohypophysial primordia of fetal rats on days 12.5 and 13.5 of gestation were treated with collagenase; some primordia were allowed to retain an association with the brain and mesenchyme, but in others the brain and/or mesenchyme were removed. These different combinations of tissues were cultured and examined by immunohistochemical techniques using antisera against pACTH and synthetic -MSH. Removal of mesenchyme alone had little effect on the development of ACTH cells as compared to primordia maintained with brain and mesenchyme. In contrast, removal of the brain with or without mesenchyme on day 12.5 resulted in a marked decrease of ACTH cells accompanied by a mal-growth of adenohypophysial tissue. Such changes were slight when the brain was separated from day 13.5 primordia. Immunoreactive -MSH cells were sparse or absent in all cases.These results suggest that in fetal rats the developing diencephalic floor is essential for differentiation of ACTH cells before day 13.5 of gestation whereas mesenchyme has no apparent effect.     

小麦不同品种和播期对发育阶段的效应

以热时间（thermal time)为尺度研究了小麦不同品种和播期对发育阶段的效应,结果表明,小麦分蘖发生的早晚以生态因子调控为主,基因型差异较小;分薛- 节期为冬性品种（京411）一生中可变性最大的生育阶段,穗分化进入单棱斯的早晚以基因型效应为主,生态因子的影响次之,单棱－二棱期为春化作用的敏感期,冬性品种晚播（3月2日）春化效应可延迟到小花原基分化期之前,小麦物候期与穗发育阶段的对应关系具有一定的可变性,冬性品种较强的春化作用增加了其生态可变叶原基数;春化过程结束前,物候发育及穗发育阶段累计GDD与相应生殖器官原基分化的数的相关性不明显,春性品种（扬麦158）的物候发育及药隔分化期之前的穗发育阶段与各类顶端原基的分化数均具有极显著的正相关关系。     

Light and electron microscopical study of Nosema eurytremae

A nuclear-polyhedrosis virus (NPV) of the silkworm, Bombyx mori, which forms an icosahedral inclusion body, was transmitted to larvae of the rice stem borer, Chilo suppressalis. Serial passages of Bombyx NPV in the alternate host by injecting the supernatant of diseased hemolymph produced inclusion bodies with cuboidal and other shapes that differed from the original shape formed in Bombyx. These different shapes increased with times of passages, and after the twelfth passage, only cuboidal inclusion bodies were formed. The icosahedral inclusion bodies in B. mori and the cuboidal inclusion bodies in C. suppressalis occluded singly enveloped virions of the same size (350 × 75 nm), but the cuboidal inclusion bodies contained only a few virions and a large number of membraneous spherical structures. The formation process of the cuboidal inclusion body differed from that of the icosahedral. At first, irregularly branched inclusion bodies containing “vacant” spaces appeared in the infected nuclei. The bodies grew larger with the deposition of protein in the spaces between the branches, and this was accompanied with the occlusion of a large number of membraneous structures formed in the vicinity of the inclusion bodies, which became cuboidal in shape.     

Developmental studies on the leaf and the extra-axillary bud ofHistiopteris incisa

Anatomical and developmental studies have been made ofHistiopteris incisa in order to obtain a reasonable interpretation of the so-called extra-axillary bud. Single, or rarely two extra-axillary buds arise on the lateral side of the petiolar base. The branch trace appears to depart from the basiscopic margin of the leaf trace. At the earliest stage of the leaf initiation, the leaf apical cell is cut off in one of the prismatic cells of the shoot apical meristem. The leaf apical cell, then, cuts off segments successively to form a well-defined group of derivatives. On the other hand, a well-recognized cell group called “outer neighboring cell group”,onc, is found adjacent to the abaxial boundary of the derivatives of the leaf apical cell. This group of cells does not originate directly in the mother cell of the leaf apical cell. The primordium of the extra-axillary bud is always initiated in the superficial pillar-shaped cell layer ofonc. The leaf primordium may consist of two parts, the distal part derived from the leaf apical cell and the basal part from the adjacent cells includingonc. These facts suggest that the extra-axillary bud is of foliar nature. This study was partly supported by a Grant-in-Aid for Encouragement of Young Scientists by the Ministry of Education of Japan; no. 374222 in 1978.     

Developmental study onHypolepis punctata (Thunb.) Mett.

The third petiolar bud ofHypolepis punctata appears on the basiscopic lateral side of the petiole above the fairly developed first petiolar bud. This investigation clarified the fact that the third bud is formed neither by the activity of the meristem of the first bud nor by the meristem directly detached from the shoot apical meristem, but is initiated in the cells involved in the abaxial basal part of the elevated portion of the leaf primordium. Thus the third bud is of phyllogenous origin. This investigation further revealed that the cells to initiate the third bud are originally located in the abaxial side of the leaf apical cell complex like the cells to initiate the first bud, but are not incorporated into the meristem of the first. After the first, second and third petiolar buds have been initiated, they are carried up into fairly high regions on the petiolar base by the intercalary growth which occurs in the leaf base below the insertion level of the first and the second buds.     

与草菇原基形成相关的过氧化物酶基因VvDyP的结构与表达分析

DyP-type过氧化物酶作为氧化物酶家族中的一员,参与了菌体氧化应激调节反应以及基质降解等过程。本研究从草菇基因组中获得一个DyP-type 过氧化物酶的编码基因,将其命名为VvDyP。对该基因进行结构分析,结果显示草菇的DyP-type 过氧化物酶编码基因全长为 2 333bp,含有8个外显子,7个内含子;开放阅读框长为1 485bp,编码494个氨基酸。通过系统发育分析发现它与灰盖鬼伞以及糙皮侧耳DyP蛋白同源性最高;分析DyP-type 过氧化物酶编码基因在草菇各个时期的表达谱情况并进行荧光定量PCR实验验证发现,草菇的DyP-type过氧化物酶编码基因只在原基中高表达,推测DyP-type过氧化物酶编码基因可以清除过量的活性氧自由基以保证原基的正常形成。     

Effects of brain and mesenchyme upon the cytogenesis of rat adenohypophysis in vitro

Summary The objective of this in-vitro study was to examine whether the diencephalic floor or the mesenchyme is involved in differentiation of LH cells in the developing rat adenohypophysis. Overall growth of the adenohypophysial tissue was retarded when the adenohypophysial primordium was cultivated after enzymatic removal of the diencephalic floor on days 11.5 and 12.5 of gestation. This malgrowth was more marked when the brain was separated on day 11.5; most expiants retained a simple cystiform structure that consisted of a few layers of undifferentiated cells. Removal of the brain also caused a highly significant decrease (P < 0.001) in the number of immunoreactive LH cells, if it was performed on day 11.5 but not day 12.5. Mesenchyme had little effect on the adenohypophysial growth or the number of immunopositive cells. Cultivation of the adenohypophysial primordium with the diencephalic floor resulted in the appearance of many immunoreactive LH cells. The number of LH cells significantly decreased, however, when the co-cultivated brain completely surrounded the adenohypophysial tissue.These results indicate that in 11.5-day-old fetal rats the diencephalic floor is indispensable for the initial proliferation of adenohypophysial primordial cells and for the early determinating process of LH cells. Once determined, the development of LH cells may proceed without the surrounding tissues. The cytodifferentiation seems to be rather inhibited when in contact with the brain. The significance of the intimate spatial relationship between developing LH cells and the surrounding mesenchyme is also discussed.     

Diverse Roles of ERECTA Family Genes n Plant Development

Multiple receptor-like kinases （RLKs） enable intercellular communication that coordinates growth and development of plant tissues. ERECTA family receptors （ERfs） are an ancient family of leucine-rich repeat RLKs that in Arabidopsis consists of three genes： ERECTA, ERL1, and ERL2. ERfs sense secreted cysteine-rich peptides from the EPF/EPFL family and transmit the signal through a MAP kinase cascade. This review discusses the functions of ERfs in stomata development, in regulation of longitudinal growth of aboveground organs, during reproductive development, and in the shoot apical meristem. In addition the role of ERECTA in plant responses to biotic and abiotic factors is examined.     

Isolation and analysis of genes specifically expressed during fruiting body development in the basidiomycete Flammulina velutipes by fluorescence differential display

Using fluorescence differential display, cDNAs specifically expressed at the primordial stage of fruiting body development were isolated from the basidiomycete, Flammulina velutipes. Seventy-five cDNAs were sequenced and compared with the amino-acid sequences of proteins in the database by BLASTX search. Significant similarity was found for 29 cDNAs coding for proteins with known function, GTP-binding protein, growth factor, ubiquitin-proteasome, cytochrome P450 and hydrophobin, all of which would be associated with fruiting body development. Seventeen cDNAs were not similar to proteins in the database and may represent unique genes that play specific roles in the process of fruiting in F. velutipes.