Studies on Nucleic Acid and Protein Synthesis and D evelopment of Male Gametnphyte of Clivia nobilis Cultured in Vitro

A simple method for culture male gametophyte (MG) of Clivia nobilis in vitro was established and the process of their development was observed. After research on dynamic of nucleic acid and protein synthesis of MG in various developmental stages by using of inhibitors and autoradiography authors found that DNA synthesis fro mrelease of tetrad to sperm only takes place in nucleus of interphase. There is no 3H-tymidine incorporation into vegetative nucleus (Vn), generative nucleus (Gn) or nucleus of sperm in 96 hours before dehiscence of anthers (BDA). The dynamic of protein synthesis is similar to the same of RNA’s. Both of them have three peaks and two intermissions. The 1st peak is in 12–9 days BDA. The 2nd is in 7–5 days BDA and intermitted from 48 hours BDA. The 3rd begins from the 1st hour after culture (AC) decleases at 6th hour AC and stops before 20th hour AC. The kind of inhibitor, the time and quanlity of treatment are affected the morphogenesis, showing the relationship to synthesis among DNA, RNA and protein and to the same between biomacromolecular and morphological development of MG.     

鳙鳃上台湾棘带吸虫囊蚴的感染

从1993年8月到1994年11月,对感染台湾棘带吸虫囊蚴的鳙鳃丝、鳃耙进行了为期16个月的调查研究表明;鳃丝、鳃耙的感染率范围为0-100%(83.33±25.47%)、(61.13±44.45%),感染强度范围分别为0-109.15(54.89±34.09)、0-125.57(41.18±49.34),囊蚴的平均密度范围分别为0-97.76(46.94±26.25),0-125.57(40.61±49.71);当鳙体长小于90mm时,鳃丝、鳃耙的感染率、感染强度、囊蚴的平均密度随着其体长的增大而增长;当体长大于90mm时,三项指标随着其体长的增大具有减小的趋势,其中鳃耙的变化规律明显;当体长大于141.7mm时,鳃耙的感染率、感染强度、囊蚴的平均密度都为0;随着鳙的生长,鳃丝囊蚴所占的比例逐渐增大,从0增加到100%,而鳃耙囊蚴所占的比例逐渐减小,从100%下降到0.       

New evidence for a role of vessel-associated cells and phloem in the rapid xylem refilling of cavitated stems of Laurus nobilis L.

Xylem recovery from embolism was studied in Laurus nobilis L. stems that were induced to cavitate by combining negative xylem pressure potentials (P_X = ?1.1 MPa) with positive air pressures (P_C) applied using a pressure collar. Xylem refilling was measured by recording the percentage loss of hydraulic conductance (PLC) with respect to the maximum 2 min, 20 min and 15 h after pressure release. Sodium orthovanadate (an inhibitor of many ATP‐ases) strongly inhibited xylem refilling while fusicoccin (a stimulator of the plasma membrane H⁺‐ATPase) promoted complete embolism reversal. So, the refilling process was interpreted to result from energy‐dependent mechanisms. Stem girdling induced progressively larger inhibition to refilling the nearer to the embolized stem segment phloem was removed. The starch content of wood parenchyma was estimated as percentages of ray and vasicentric cells with high starch content with respect to the total, before and after stem embolism was induced. A closely linear positive relationship was found to exist between recovery from PLC and starch hydrolysis. This, was especially evident in vasicentric cells. A mechanism for xylem refilling based upon starch to sugar conversion and transport into embolized conduits, assisted by phloem pressure‐driven radial mass flow is proposed.     

热休克诱导鳙鱼四倍体的研究

采用热休克法研究了诱导鳙鱼四倍体的可能性和处理条件。结果表明:1)恰好在卵子开始第一次卵裂前用39—42℃水浴处理1—3分钟,可获得较高频率的四倍体;2)开始处理的时间至关重要,提前或推迟处理导致几乎全部死亡或四倍体频率大大下阵;3)热休克组的孵化率显著下降,畸形率明显升高;4)含高频率四倍体的热休克组的细胞分裂和胚胎发育延迟。     

Effects of experience on feeding success by larval white seabass, Atractoscion nobilis

Laboratory experiments on larval white seabass, Atractoscion nobilis , showed that first feeding success on mixed zooplankton was zero, and less than 5% on Artemia nauplii , for larvae of different sizes. Experience increased success from 20% after 2 days to 69% after 14 days when larvae fed on Artemia nauplii , and to 42% after 4 days of feeding on zooplankton. This increase was attributed to learning in larvae less than 5·0 mm s.l. , and in part to size-related factors in larvae greater than 5·0 mm s.l.     

Richness and diversity of helminth parasite communities in the common carp and in three more recently introduced carp species

It can be predicted that common carp Cyprinus carpio , as an introduced species, would harbour poor helminth infra-communities but that these would nevertheless be richer than those in three other species of carps introduced into Europe in recent decades. These predictions were tested by comparing the helminth infra-communities of common carp, Ctenopharyngodon idella, Hypophthalmichthys molitrix and Aristichthys nobilis reared under similar conditions in a fish farm. Data were presented on species richness of total helminth infra-communities, and on richness and diversity of gill, eye and intestinal infra-communities separately. These confirmed that common carp helminth infra-communities were poor and that they were no richer than those of the three other species of carp. This situation in the farm was considered to be representative of the situation in natural habitats in Europe. It is suggested that the poor infra-communities in common carp reflect the facts that their helminth communities are composed mainly of specialists, that they are not readily susceptible to invasion by specialists of other fish hosts and that, as introduced species, they have not had sufficient time to acquire many generalist helminths from native species of fish. The difference in time between the introduction of common carp into Europe centuries ago and the introduction of the other three species of carps decades ago is not sufficient to produce any significant differences in the richness and diversity of their helminth infra-communities.     

鲢鳙对鱼粪消化利用的研究

以鱼粪代表天然水体中有机碎屑,研究鲢、鳙对鱼粪的消化利用,并评价有机碎屑在鲢、鳙营养中的作用。在实验室条件下(水温30℃,溶氧6毫克/升以上,pH7—8,光照度2800lx),收集鲢、鳙摄食微囊藻后排出的粪作为试验用饲料。在限制摄食量的条件下,测定鱼对鱼粪的消化率及研究鱼粪对鲢、鳙生长的影响。研究结果是:(1)鲢、鳙对鱼粪中干物质消化率分别为58.54±9.53％及68.57±8.98％。其中蛋白质消化率分别为74.49±7.96％及80.41±9.02％,脂肪消化率分别为90.23±15.33％及84.24±6.96％,碳水化合物分别为49.14±20.67％及60.36±11.29％;(2)经10天饲养,鲢、鳙体重增重率分别为6.25±3.46％及7.80±3.18％。根据鱼粪的营养价值及鲢、鳙对鱼粪的能量转化率,表明鲢、鳙鱼粪在鲢、鳙营养中起着一定作用。     

鳙鱼ARISTICHTHYS NOBILIS早期发育的一些生物化学上的变化

本实验第一部分对鳙鱼卵及胚胎在不同的发育时期蛋白质合成的速度进行了研究,实验采用微量克氏定氮法,对鳙卵从未受精卵到受精卵、尾芽期和出膜期,共测定了十三个不同的发育时期。实验结果表明了在鱼的不同胚胎发育时期蛋白质合成速度有着明显的差异。 实验的第二部分对鳙鱼胚胎发育过程氨基酸组成和氨基酸含量进行了测定,其结果显示出鳙鱼卵和胚胎的各发育时期氨基酸的组分十分相似,但氨基酸的含量在各个时期是有差异的。     

几种观赏花卉的组织培养

自1982年来,我园用组织培养的方法对君子兰、五星花、重瓣矮牵牛、贴梗海棠、药百合等观赏花卉进行了实验,均取得了成功,其中部份试管苗移栽土壤成功,并已开花。下面将实验结果小结如下: 1.君子兰Clivia nobilis