中国热带地区的半知菌Ⅱ.广东部分假尾孢菌(英文)

本文报道广东热带地区的部分假尾孢菌30种,其中有一个新种和一个中国新记录种,即寄生在咖啡（CoffeaarabicaL．）上的咖啡假尾孢（PseudocercosporacoffeigenaGuo＆Liu．nov）和生在假（PiersarmentosumROxb）上的糙叶胡椒假尾孢[Pseudocercosporapiperis－muricati（Yen）Yen]。文种为新种提供了拉丁文简介并附图,对新记录种进行了讨论。研究的标本保存在中国科学院微生物研究所真菌标本室（HMAS）。     

Studies on Highly Efficient Planting of Transgenic Cotton

Foreign insecticidal genes were transferred into 4 upland cotton ( Gossypium hirsutum L. ) cultivars by Agrobacterium-mediated transformation. It was found that planting style has a critical influence on the survival rate of the transgenic plantlets. Direct transplanting, culturing in liquid medium or vermiculite before transplanting were not proper for planting transgenic plantlets. The survival rate was quite low and hardening time was rather long. Graft could greatly enhance the survival rate and efficiently reduced the hardening time, thus paves the way for cotton improvements through genetic engineering and other biotechnology.     

Organogenesis and Plantlet Regeneration in Vitro of Populus euphratica

The research of organogenesis and in vitro plantlet regeneration of Populus euphratica Oliver was carried out using the tender shoots from mature tree as initial explants and MS medium as the basic medium. The effects of plant growth regulators (PGR) on the regeneration were compared. The results showed that the concentration of PGR was not strictly required for the organogenesis of the excised organs and callus, but the ratio of BA to NAA was important. Calli could be induced from the excised leaves and stems cultured on the medium with 0.5 mg/L BA and 0.5 mg/L NAA. The embryonic callus could be multiplied in dark on the medium supplemented with 0.25 mg/L BA and 0.5 mg/L NAA. For the adventitious bud regeneration of the leaf and callus, supplement with 0.5 mg/L BA and 0.1 mg/L NAA was appropriate, giving a regeneration frequency of 82.9% and 100%, respectively. The suitable level of BA and NAA for the excised stem's was 0.1 mg/L and 0.01 mg/L respectively, yielding a regeneration frequency of 83 %. Rooting occurred on the MS medium with half strength of macronutrient and addition of 0.015 mg/L NAA, and the rooting rate could reach up to 86.2%. The techniques of somatic cell cloning of P. euphratica was established in vitro. The problems of deterioration of the subcultured shoots were also discussed.     

Effects of Strong Light and Active Oxygen on Photosynthesis in Soybean

With the use of chlorophyll fluorescence technique, it was found that the net photosynthetic oxygen evolution rate decreased after strong light (2 000 μmol· m-2·2-1 ) treatment for two hours in soybean ( Glycine max L. ) leaves. The chlorophyll fluorescence parameters, Fm/Fo, Fv/Fm, ФPSII, qp and qN decreased along with the increase of light intensity. In strong light, exogenous active oxygen H202、·OH and 'O2 were harmful to soybean leaves. The destruction of 'O2 and·OH to leaves was most evident, as was shown that Fv/Fm and PS H decreased significantly. The antioxidants DABCO, mannitol, ascorbate and histidine protected the leaves, but weakly, from strong light. In darkness, the SOD inhibitor sodium diethyldithiocar- bamate (DDC) had no significant effect on Fm/Fo and Fv/Fm, but NAN,, the ascorbate peroxidase (APX)inhibitor, significantly decreased Fm/Fo, Fv/Fm and ФPS II. In strong light, however, beth DDC and NaN3 reduced the above-mentioned fluorescence parameters, but NaN3 was more effective than DDC. The results suggested that photoinhibition did take place in soybean leaves under strong light, and it was related to active oxygen in vivo.     

A prourokinase-RGDS chimera——Construction, expression and characterization

A tetrapeptide, RGDS, was inserted into proUK kringle domain G118-L119 by the construction of a mutant proUK-RGDS gene. The gene was expressed in the baculovirus expression system. Immunoaffinity chromatography was used to purify the chimera and protein with purity over 90% was achieved. The chimera was tested for its platelet membrane binding function and showed a calcium-dependent platelet binding activity. Amidolytic activity of the chimera was tested. The result indicated that specific amidolytic activity of plasmin activated chimera was 62000 IU/mg, comparable to the previously reported 65 355 IU/mg of plasmin activated natural proUK. Activation of plasminogen by the chimera after plasmin treatment followed Micbieal-Menten kinetics, and the Km was 0.97 μmol/L, which was also comparable to 1.64 μmol/L of native urokinase. The chimera also showed intensive ability to inhibit platelet aggregation in vitro. These results indicate that this chimera might be useful as a bifunctional thrombolytic agent.     

核酸代谢抑制剂对水稻光敏核不育性的影响

在稻穗分化的二次枝梗期后,观察比较了叶片喷施核酸代谢抑制剂5-FU对水稻光敏核不育性及幼穗发育的影响,结果表明：长日照下,5-FU在使农垦58S穗长缩短、颖花数减少的同时,却使其抽穗提前,可育性得到一定程度的恢复;5-FU处理还使农垦58的抽穗被完全阻止。在短日照下,5-FU处理则使农垦58S与农垦58在穗长与颖花数减少的同时,其抽穗反被延迟,可育性受到抑制而结实率显著降低,上述效应还可被随后施用的恢复剂乳清酸所弱化。因此可以认为光敏核不育现象与稻穗发育中核酸代谢的改变有关。