MEGAGAMETOPHYTE AND NUCELLUS IN RESTIONACEAE AND FLAGELLARIACEAE

Restionaceae are characterized by Polygonum-type development, a well-developed hypostase, the presence of starch grains in the mature female gametophyte, and a thick nucellus that is uniseriate at the micropylar end. Flagellaria indica differs in these characters. In general, proliferation of antipodals occurs in South African taxa of Restionaceae but not in Australasian taxa. The presence of multiplied antipodals is the usual condition in the allied family Poaceae, but the sporadic occurrence of this character in Restionaceae cannot be used to support the view that the two families are sister groups.     

EFFICACY OF WIND POLLINATION: POLLEN LOAD SIZE AND NATURAL MICROGAMETOPHYTE POPULATIONS IN WIND-POLLINATED STABEROHA BANKSII (RESTIONACEAE)

A detailed examination was made of the numbers of pollen grains and microgametophytes occurring on stigmas of a dioecious, wind-pollinated species, Staberoha banksii. The number of pollen grains per pistil ranged from 0 to over 100; and the mean pollen load size per pistil per plant varied from 4.4 to 28. Distance to the fourth nearest male plant was used as a measure of local pollen availability and accounted for 63.5% of the between-plant variation in pollen load size. In contrast, the number of microgametophytes did not show a leptokurtic decline with increasing distance from a pollen source. On average there were 5.19 microgametophytes per ovule, which is higher than all comparable data for insect-pollinated taxa, and 66% of the stigmas had two or more microgametophytes. Given that there is a single ovule per flower, there is considerable potential for gametophytic competition. Seedset was very high, averaging 93%, and showed no significant decline in isolated female plants. We suggest that the quantity of pollen is not limiting fertilization in this population and that wind may therefore be highly effective as a pollen vector.     

PACEMAKERS IN NITELLA : II. ARRHYTHMIA AND BLOCK

Many forms of irregular rhythm and of partial block occurring in the vertebrate heart can be duplicated in Nitella. In order to observe these phenomena the cells of Nitella are kept for 6 weeks or more in a nutrient solution. They are then exposed for 3 hours or less to 0.01 M NaCl, NaSCN, or guanidine chloride, which reduce the time required for the action current to about 1 second (the normal time is 15 to 30 seconds). A pacemaker is established at one end of the cell by placing it in contact with 0.01 M KCl. This produces action currents at the rate of about 1 a second. Apparently some parts of the cell are unable to follow this rapid pace and hence fall into irregular rhythms (arrhythmia) and fail to register all the impulses (partial block).     

老年大鼠血管α1肾上腺素受体及其亚型的改变

本工作用离体与整体实验方法,研究了老年(18月龄)与年轻(3月龄)大鼠血管中 α_1肾上腺素受体储备和 α_1(?)与 α_(1b)亚型比值的差别。在离体实验中用机械方法分离血管,用 Krebs 溶液灌流,在灌流液中加入 α_2和 β肾上腺素受体拮抗剂,然后用去甲肾上腺素(NE)激动 α_1受体。结果显示;老年大鼠主动脉、肾动脉和肠系膜动脉由去甲肾上腺素(NE)引起的最大收缩反应与年轻大鼠无显著差别,但浓度-效应曲线显著右移,功能性解离常数 K_A 值不变,而 K_A 与EC_(50)的比值减小。此外,在老年大鼠主动脉和肠系膜动脉血管,选择性 α_(1b)亚型拮抗剂 CEC对 NE 引起的缩血管效应的阻断作用显著减弱,硝苯吡啶(选择性阻断 α_(1a) 亚型的效应)对 NE 缩血管效应的阻断作用显著增强。整体实验显示老年大鼠硝苯吡啶的降血压作用比年轻大鼠增强,在用硝苯吡啶的基础上给予苯肾上腺素升血压作用减弱。上述结果提示:与年轻大鼠相比较,老年大鼠 α_(1-) 肾上腺素受体储备减少,α_(1a) 亚型相对 α_(1b)亚型的比率增高。     

对开蕨属导管的发现

通过对开蕨的解剖学研究,发现在根的次生木质部中,存在单穿孔倾斜乃至横的穿孔板的孔纹导管,螺纹加厚明显,是蕨类植物中一种新类型的导管。     

胃癌及胃壁组织内淋巴管分布的研究

本文首次用５′－Ｎａｓｅ－ＡＬＰ双重组织化学方法观察了２０例胃癌组织和癌旁胃壁组织内淋巴管的细微分布。在光镜下毛细淋巴管和淋巴管５′－Ｎａｓｅ染色强阳性,管壁显示明显的棕色或深棕色,而毛细血管和血管的ＡＬＰ反应显示强阳性,管壁呈明显的蓝色。据此可将淋巴管、血管区别开来、本研究发现胃癌组织内有较多的淋巴管、毛细淋巴管以及较多的棕色实性条状组织,这些条状物可能是新生的毛细淋巴管。上述结果为研究癌组织内淋巴管的分布及胃癌淋巴道转移,提供了可靠的实验方法。     

大鼠脑缺血再灌注血管壁NOS和ICAM-1的表达

一氧化氮（NO）和一氧化氮合酶（NOS）与脑血管功能有重要关系,细胞间粘附分子1（ICAM－1）可由脑缺血／再灌注诱导产生并与脑组织损伤密切相关,本实验用免疫组织化学和NADPH－d酶组织化学方法,观察了SD大鼠实验性脑缺血再灌注内皮细胞ICAM－1和NOS的表达,结果显示正常对照组大鼠脑血管ICAM－1免疫组织化学显色为阴性或弱阳性反应,再灌注2h,ICAM－1阳性反应明显增强,与对照组相比,P＜0.01。随再灌注至16h,ICAM－1表达增加近一倍。脑缺血1h缺血侧侧脑血管壁开始出现NOS的阳性表达,与对照组相比,P＜0.01,再灌注2h,NOS表达最多,随后逐渐下降,结果提示脑缺血再灌注与ICAM－1和NOS表达升高有关。     

中国柱隔孢菌属及其近似属的研究II.

本文报道柱隔孢菌属二新种,二个中国新记录种。新种是紫荆生柱隔孢Ramularia cercidis, 寄生在云实亚科(Caesalpiniodeae)紫荆(Cercis chinensis)上;丁香柱隔孢Ramularia syringae,寄生在木犀科(Oleaceae)丁香属Syringa sp.上。新记录种是极细柱隔孢Ramularia angustissima和稍厚柱隔孢R. crassiuscula。文中为新种提供了拉丁文描述和附图。研究标本保存于云南农业大学真菌标本室(MHYAU)。     

SUPPRESSED BUDS EMBEDDED IN THE BARK ACROSS THE BOLE AND THE OCCURRENCE OF THEIR CIRCULAR VESSELS IN FICUS RELIGIOSA

A latitudinal suppressed bud which is embedded in the outer bark across the bole of Ficus religiosa is described. It might be very long and extend over half of the bole's circumference. The suppressed bud contains cambium which forms secondary xylem and phloem. Circular vessels and circular sieve tubes were frequently observed in the base of the bud as well as above its constriction areas.     

REPRODUCTION IN ZONARIA FARLOWII II. CYTOLOGY AND ULTRASTRUCTURE1

The development of spores and eggs of Zonaria farlowii was studied with light and electron microscopy. Oogonia require a lunar month to develop and are produced in periodic crops. The sporangia, on the other hand, are longer in developing and on a particular plant do not become mature all at the same time. Differences in size, content, and products of sporangia and oogonia have been found. One of the quantifiable differences is in the amount of osmiophilic substance, presumably oil, present in the 2 cells. This substance is more abundant in the sporangium, a cell which produces 8 reproductive spores. These differences are particularly interesting since the embryology of sporic and zygotic germlings has been found to be identical, while ontogeny of spores and eggs differs. The findings of this study are discussed in view of possible relationships between microstrtrclitral features of spores and fertilized eggs and their subsequent development.