水稻病毒的吸收光谱和荧光光谱

本文报导水稻簇矮病毒(RBSV),水稻矮缩病毒(RDV),水稻东格鲁病毒(RTV),水稻齿矮病毒(RRSV)和水稻草矮病毒(RGSV)等的吸收光谱和荧光光谱.结果表明:不同病毒有不同的吸收光谱带和荧光光谱带.它包括主峰,各次峰及其轮廓.通过不同相对强度的光谱,可以判断其浓度.这些光谱可以反映病毒的某些结构信息.同时通过光谱也可以鉴别水稻病毒的类型.     

高粱叶片磷酸烯醇式丙酮酸羧化酶溶液构象状态的紫外差示吸收光谱研究

PEP诱导产生的差光谱在237nm是一强负峰,在252nm附近呈宽负峰。Mg~(2+)产生的差光谱在275nm附近为正的阔峰,在237nm处为一负峰。PEP、Mg~(2+)共同与酶作用的差光谱在263nm附近呈宽的负峰。正效应剂G6P、Gly及GG分别存在条件下PEP羧化酶的差光谱亦各具明显差异,在270nm以下光区内尤其显著。在284nm和291nm为两个负峰,Gly诱导的峰强度大于G6P的,而GG复合效应剂对此两峰的影响表现很大的协同作用。Mal作用于酶的差光谱在246nm处有一负峰。     

SOME ASPECTS OF SELECTIVE ABSORPTION

1. A mechanism exists in Valonia which prevents certain substances (Na, Mg, Ca, SO₄) from reaching as high a concentration inside the cell as in the sea water which surrounds it. 2. A trapping mechanism also exists which causes K to accumulate in the cell in a concentration far in excess of that found in sea water. Practically all the K in the cell exists in the form of KCl. 3. The concentration of Cl does not differ greatly within and without. 4. These facts are not in harmony with present theories regarding the accumulation of K in living cells.     

华山松吸收光谱及叶绿素荧光特性的地理变异

利用分离的叶绿体作实验材料,发现华山松(Pinus armandi Franch.)南方种源的4阶导数吸收光谱在680nm处峰值较大,在670nm处峰值较小,而北方种源中出现了在680nm处峰值较在670nm峰值小的类群,推断北方种群反应中心活力有下降趋势。南、北种源之间的低温(77K)荧光发射光谱有明显差异,PSⅠ、PSⅡ发射峰位置出现地理变动。低温荧光激发光谱分析表明,地理变异主要发生在叶绿素a的分子状态上。研究还表明,完整的针叶因为有角质层、松脂等物质干扰,检测不出光谱的差异,不是理想的实验材料。     

LEAF TRICHOMES OF SOME PARTHENIUM SPECIES

Guayule (Parthenium argentatum), a native shrub of the Chihuahuan desert, contains rubber. Guayule has been crossed with other Parthenium species in an attempt to improve its agronomic characteristics. The resulting hybrids show intermediate morphologies. Each Parthenium species has a characteristic combination of leaf trichomes. In order to recognize the contribution of each parent in future studies of hybrids, characteristics of leaf trichomes of the following Parthenium species were studied: P. tomentosum, P. fruticosum, P. Schottii and P. rollinsianum. All species studied had two or more types of trichomes, and, in some species, trichomes of upper and lower epidermal surfaces were different. The prominent trichomes on upper epidermis of P. tomentosum and P. fruticosum were simple, uniseriate, conical trichomes, which also were observed on both epidermal surfaces of P. Schottii. Extremely long, narrow, simple, whiplike, trichomes formed a dense cover on both surfaces of P. rollinsianum and on the lower surfaces of P. tomentosum and P. fruticosum. Simple, uniseriate, cylindrical trichomes, and biseriate, glandular trichomes were observed in all four species.     

溶菌酶中水分子的红外吸收光谱

本文报导了不同水含量的溶菌酶中水的红外吸收光谱的测量结果.室温下,在远离纯水OH带及OD带的两侧分别出现高频与低频带,峰的位移大小随水含量的不同而改变.低温下,当R(克水/克蛋白)>0.2后,比值A./A.随水含量增大而增大.本文对室温下高频及低频峰的可能原因及与水的冻结过程的联系进行了讨论.     

SOME EFFECTS OF TANNIC ACID AND OF LEAF EXTRACTS WHICH CONTAIN TANNINS ON THE INFECTIVITY OF TOBACCO MOSAIC AND TOBACCO NECROSIS VIRUSES

The inhibition of infection by tobacco necrosis and tobacco mosaic viruses by tannic acid, and by extracts of raspberry and strawberry leaves, was associated with the precipitation of the viruses. Precipitation and inhibition were reversible, and infective virus was obtained from the precipitate formed between the viruses and tannins. Infectivity was fully restored by diluting mixtures of virus and tannin adequately and partially restored by adding alumina or nicotine sulphate.
Viruses and tannins are thought to form non-infective complexes, in which the virus and tannin components are held together by co-ordinate linkages or hydrogen bonds.
Macerating tobacco leaves infected with tobacco mosaic virus together with raspberry leaves greatly decreased the infectivity of the extracts; adding nicotine sulphate to the mixture of leaves before it was ground increased the infectivity, even though nicotine sulphate alone decreases the infectivity of tobacco mosaic virus. Even in the presence of nicotine sulphate, much of the virus was precipitated by substances from the raspberry leaves.
Extracts of roots of Fragaria vesca plants, infected with a tobacco necrosis virus, were more infective when made by macerating the roots with four times their weight of buffer at pH 8 than when made without buffer. Various methods are suggested for facilitating the transmission of viruses from plants that contain tannin.     

RELATION OF FLOWER COLOR TO OPTICAL-DENSITY SPECTRA OF INTACT TISSUE AND OF ANTHOCYANIN EXTRACTS

Data from measurements of optical density of intact tissue and of anthocyanins in extracts resolved on cellulose thin layer plates were compared with visual evaluations of color quality and intensity in poinsettia, rose, and snapdragon. Visual evaluation was in good agreement with both instrumental and chemical determinations. However, the number or kinds of anthocyanins present could not be predicted from the visual evaluation or from the spectra of the fresh tissue. Data from the resolved extracts did not provide a basis for predicting the optical-density spectrum or the color of the intact tissue. In addition to the genetic factors which have been shown to control (1) the type of anthocyanin, (2) the amount of anthocyanin, and (3) the distribution of anthocyanins within the flower, we suggest another group of genes which apparently affect color through control of structural modification of individual anthocyanins in the living cell through shift in pH, metal chelation, and/or copigmentation. Such genes are apparently responsible for the modification of red color within the Wh Wh genotype of poinsettias containing both pelargonidin and cyanidin glycosides and for a very similar pink color in a snapdragon and a rose, each containing a single anthocyanin, a pelargonidin glycoside, and a cyanidin glycoside, respectively.