Sucrose and Nitrogen Supplies Regulate Growth of Maize Kernels

The growth of maize (Zea mays L.) kernels depends on the availabilityof carbon (C) and nitrogen (N) assimilates supplied by the motherplant and the capacity of the kernel to use them. Our objectiveswere to study the effects of N and sucrose supply levels ongrowth and metabolism of maize kernels. Kernel explants of Pioneer34RO6 were culturedin vitro with varying combinations of N (5to 30 m M) and sucrose (117 to 467 m M). Maximum kernel growthwas obtained with 10 m M N and 292 m M sucrose in the medium,and a deficiency of one assimilate could not be overcome bya sufficiency of the other. Increasing the N supply led to increasesin the kernel sink capacity (number of cells and starch granulesin the endosperm), activity of certain enzymes (soluble andbound invertases, sucrose synthase, and aspartate aminotransaminase),starch, and the levels of N compounds (total-N, soluble protein,and free amino acids), and decreased the levels of C metabolites(sucrose and reducing sugars). Conversely, increasing the sucrosesupply increased the level of endosperm C metabolites, freeamino acids, and ADPG-PPase and alanine transaminase activities,but decreased the activity of soluble invertase and concentrationsof soluble protein and total-N. Thus, while C and N are interdependentand essential for accumulation of maximum kernel weight, theyappear to regulate growth by different means. Nitrogen supplyaids the establishment of kernel sink capacity, and promotesactivity of enzymes relating to sucrose and nitrogen uptake,while sucrose regulates the activities of invertase and ADPG-PPase.Copyright 1999 Annals of Botany Company Zea mays, maize,, invertase, ADPG-PPase, media composition, sucrose, nitrogen, C/N.     

Leaf Water Potential and the Rooting of Cuttings under Mist and Polythene

The relationship between leaf water potential and rooting was investigated in cuttings of Rhododendron (Hardy Hybrid) ‘Mrs. W. Agnew’, Ceanothus thyrsiflorus Esch. and Hebe (Garden Hybrid) ‘Caledonia’ (of the ‘Mrs. Winder’ group), during propagation under mist and polythene. Water potentials well below –10 bars frequently occurred and low mean water potentials related to poor rooting. Propagation under polythene gave better results than mist in the lower radiation conditions of winter but the reverse occurred under high radiation conditions. Treatment of cuttings with a poly-vinyl resin antitranspirant coating temporarily increased leaf water potentials in the consistently humid conditions under polythene but not under mist. The coating peeled and lost its effectiveness within 6 weeks. Multiple regression analysis showed that much of the variation in water potential in cuttings under mist could be accounted for by inclusion of three variables, viz. current day's radiation, number of days from insertion of the cuttings and either the previous day's leaf water potential or radiation. Under polythene the influence of yesterday's water potential was relatively unimportant, probably because cuttings were able to take up water overnight from condensation on the under surface of the polythene. For optimal rooting, propagation procedure must ensure that high leaf water potentials are maintained, but conventional methods do not always achieve this.     

Emergency Health Supplies: Present Status of Procurement and Control

Until recently there was no substantial reserve of health supplies in Canada capable of supporting major peacetime or wartime disasters. In 1952, an $18,000,000 stockpile was authorized by the Federal Government of Canada. Purchases were made to a total of $15,500,000 with deliveries to exceed $13,000,000. Over $6,000000 worth of supplies was distributed to eight regional depots across Canada in safe and strategic locations. Plans were made for release and control of supplies to provincial governments for use at all levels of control, and a Resources Planning Unit has been organized. In Canada, undergraduate students in pharmacy receive special civil defence instruction in emergency health supplies service.     

宠物结核病的危害及其防治

随着生活水平的提高,宠物的数量和种类增长迅速。结核病是目前病死人数最多的人兽共患病,犬、猫和鸟类都能感染发病,对人类,尤其是免疫抑制人群威胁很大。监测和防治宠物结核病对人类结核根除计划具有重要意义。     

Occurrence of Giardia and Cryptosporidium spp. in Surface Water Supplies

[This corrects the article on p. 2610 in vol. 57.].     

Malformations of Central Nervous System and Softness of Local Water Supplies

The mean annual prevalence at birth of congenital malformations of the central nervous system for the three years 1964-6 in 48 local authority areas in South Wales was negatively correlated (r = -0·402, P<0·01) with estimates of the mean total hardness of the related water supplies.The mean annual perinatal mortality rate from anencephalus for the five years 1963-7 in 58 county boroughs in England and Wales was also negatively correlated with estimates of the mean total hardness (r = -0·220, P>0·05) and calcium content (r = -0·289, P<0·05) of the related water supplies.It is concluded that the relationship between these associations may well be secondary. Analytical epidemiological studies of the association are called for.     

Absorption and Distribution of Copper in Plants with Sufficient or Deficient Supplies

Wheat, red clover and ryegrass were grown in flowing solutionculture with sufficient (+ Cu) and deficient (–Cu) suppliesof copper. The rates of Cu absorption (µg g^–1 dryroot day^–1) did not differ greatly between species ineither treatment. Wheat plants, when transferred from the –Cu to the +Cu treatment, absorbed Cu at a much slower rate thanthose which had remained throughout in the + Cu treatment. Inall plants considerable proportions of the absorbed Cu wereretained in the roots, even when the plants were Cu-deficient,and the concentration in roots usually exceeded that in anypart of the shoots in both treatments. Transferring wheat plantsfrom the +Cu to the –Cu treatment decreased the concentrationin all plant parts except old leaves; similarly, transferringfrom the –Cu to +Cu treatment increased the concentrationin all parts of the shoots, execept old leaves, and in the roots. Lolium perenne, Trifolium pratense, Triticum aestivum, ryegrass, red clover, wheat, absorption, copper, flowing solution culture     

自动设别技术在医院药品供应和管理体系中的应用

?????? 运用医院电子化药品物流平台,贯穿整个医院药品物流供应过程,并结合运用条形码扫描自动识别技术来判别调配药品以及数量的准确性,同时客观记录人员绩效管理数据。盘点误差由使用前的0.24%,降至零;2011年度验收拒收药品共74次;专业技术人员配备由7名降至5名。整个电子化药品物流平台贯穿医院药品物流始终,能确保入院药品信息准确,杜绝调剂差错,有效提升人员绩效管理,真正发挥药师应有的专业特长,更好地为患者服务。

     

Rhamnose Biosynthesis Pathway Supplies Precursors for Primary and Secondary Metabolism in Saccharopolyspora spinosa

Rhamnose is an essential component of the insect control agent spinosad. However, the genes coding for the four enzymes involved in rhamnose biosynthesis in Saccharopolyspora spinosa are located in three different regions of the genome, all unlinked to the cluster of other genes that are required for spinosyn biosynthesis. Disruption of any of the rhamnose genes resulted in mutants with highly fragmented mycelia that could survive only in media supplemented with an osmotic stabilizer. It appears that this single set of genes provides rhamnose for cell wall synthesis as well as for secondary metabolite production. Duplicating the first two genes of the pathway caused a significant improvement in the yield of spinosyn fermentation products.