BACTERIAL CANKER OF STONE-FRUITS: IV. INVESTIGATION OF A METHOD FOR MEASURING THE INOCULUM POTENTIAL OF CHERRY TREES

Pseudomonas mors-prunorum Wormald, the organism causing bacterial canker of stone-fruits, was present on healthy cherry leaves during the autumn in numbers sufficient to suggest that they were the main source of inoculum for the infection of stems and branches. Quantitative estimates of the pathogen could be obtained by shaking leaves in water and plating out the washings. This method was examined in detail as a possible means of comparing the inoculum potentials on different cherry varieties.
The numbers of the pathogen varied considerably between leaves and between branches, but not between trees of the same variety. It was estimated that a sample of 192 leaves, eight from each of twenty-four different branches would be adequate to show differences between varieties if sufficiently replicated in time. The accuracy of a twenty-four branch sample was tested by comparing parallel samples from two separate groups of trees of the same variety. There was a highly significant correlation between the numbers of bacteria obtained from the two series of samples. From the error variance in an analysis of variance, it was calculated that five successive samples would show a significant difference between two such groups of trees if one exceeded the other by 54%.
It was necessary to wash leaves for 4 hr. or more, depending on temperature, to recover all the bacteria from the leaf surfaces. At temperatures lower than 27° C. however, bacterial growth intervened before this stage was reached. At laboratory temperatures a period of 4 hr. washing was found to be most suitable for comparing varieties and gave 80–90% recovery of bacteria without errors due to growth.
A characteristic flora of non-parasitic bacteria was observed on cherry trees, coexisting with the pathogen on the leaf surfaces. The fungus Pullaria pullulans was also extremely abundant.     

细菌L型与喉癌关系的研究

用组织切片革兰氏染色、免疫组织化学染色等方法,对８５例喉癌重新切片,进行细菌Ｌ型检查,结果发现有６５例革兰氏染色Ｌ型菌阳性,其阳性率为７６．５％。５３例（６４．７％）Ｌ型抗体免疫组化染色和革兰氏染色Ｌ型菌均阳性,两者总符合率为８３．５％。细菌Ｌ型呈多形性,分布于癌巢、癌间质,常聚集成堆,也可呈散在性分布。５８例（６８．２％）癌细胞胞浆内也见到Ｌ型菌。提示细菌Ｌ型感染与喉癌关系密切。     

宫内节育器与细菌及其L型相关性的研究

自１９９５年６月－１９９８年底于山东医科大学第一附属医院计划生育门诊选择１４８例患者,放置有活性的宫内节育器（ＩＵＤ）３２例（均为有尾丝者）为Ａ组,放置惰性ＩＵＤ者５６例Ｂ组;未放置ＩＵＤ的育龄妇女,其中无生殖器炎症者３０例为Ｃ组,有盆腔炎症者３０例为Ｄ组。各组均采用无菌操作取出宫腔内分泌物,同步进行了需氧菌、厌氧菌及其Ｌ型菌的他离培养;Ａ、Ｂ两组同时取出ＩＵＤ做需氧菌培养,其培养阳性结果是：Ａ、     

STUDIES IN THE BACTERIAL DIE-BACK AND CANKER DISEASE OF POPLAR

The bacterial die-back and canker of poplar is characterized by dark necrotic areas in the leaves, die-back accompanied by cracks in the bark of 1–4-year-old branches, and by cankers on the trunk and branches of different ages. The cankers may be 'closed' or 'open' and when moist exude slime containing bacteria.
The disease is caused by Pseudomonas syringae f. sp. populea , a new forma specialis closely resembling Ps. syringae in bacteriological characters but differing from it in parasitism. The association of the slime with the bacteria is essential for the production of typical lesions.
Inoculations with the pathogen alone, or in association with other organisms produce atypical symptoms.
The bacteria attack the cortical parenchyma and occasionally invade the xylem vessels.     

ABSORPTION OF NUTRIENTS AND PLANT GROWTH IN RELATION TO HYDROGEN ION CONCENTRATION

The absorption of nutrients depends to a large extent on the reaction of the substrate. At maximal growth the intake of salt is at minimum. Different ions are very differently affected. The intake of water is independent of the absorption of salts.