Ovarian histology of stunted pond-reared Macrobrachium rosenbergii females

The present study describes the ovarian histology of stunted freshwater prawn Macrobrachium rosenbergii. The ovarian maturation of stunted animals was examined and compared with similar‐aged normal females. Ten animals of the stunted group and each maturation stage of the normal group were sampled from the same pond and had their ovaries removed for histological analysis. Body weight, body length, ovarian weight and gonadosomatic index (GSI) were recorded for each female. The diameters of the different oocyte types were compared among groups through histological assessments. The ovarian histology of stunted M. rosenbergii females indicated that although the somatic growth is severely affected (7.6 g), some energy has been placed on the vitellogensis. Stunted females showed the simultaneous occurrence of previtellogenic, vitellogenic and mature oocytes in their ovarian tissue, but overall oocyte diameter and GSI (1.02%) were significantly affected when compared with normal females.     

植物生长调节剂处理对梨矮化砧木SPRB15快速成苗影响的研究

为了确立梨矮化砧木快速成苗技术,采用不同植物生长调节剂处理,研究了植物生长调节剂对梨矮化性砧木SPRB15快速成苗的影响。结果表明:间隔7天连续2次喷布GA4 7100 mg/L的处理4的地径生长量、苗高生长量均为最大,是本试验中的最佳处理。其次是2次喷布GA3100 mg/L的处理2,依次为2次喷布GA4 750 mg/L的处理3,2次喷布GA350 mg/L的处理1,2次喷布BA 250 mg/L的处理5。据此结果认为:GA4 7和GA3对于梨矮化性砧木SPRB15幼苗苗木的生长具有显著的促进效果;BA对于梨矮化砧木SPRB15苗木侧芽的萌发具有显著的促进效果。     

The influence of stunted body size on the reproductive ecology of bluegill Lepomis macrochirus

Abstract – Although stunting is a common phenomenon in fish populations, the consequences of stunted body size on the reproductive ecology of individuals has received little attention. The present study compares the reproductive ecology of bluegill in established stunted and non-stunted populations. Three ponds (two non-stunted and one stunted) were monitored for spawning activity throughout the summer. Parental male bluegill from both non-stunted populations were older, larger, and had greater mating success (number of eggs or fry within nests) than parental males in the stunted population. Stunted bluegill also experienced a shortened reproductive season owing to the delay in onset of spawning. The present study demonstrates that individual size and population size structure can have a marked influence on the reproductive ecology of bluegill.     

杉苗矮化线虫病的症状及病原形态观察

本文首次报道了在三明市杉木苗圃中由矮化线虫（Tylenchorhynchussp.）引起的杉木苗（Cunninghamia Lanceolafa）衰退病,描述了病害的症状和病原线虫形态特征。在发病杉苗的根部和根围土壤中可发现许多矮化线虫。杉苗受侵后地上部生长衰退、矮化和黄化,根系生长不良,侧根少,根尖肿大,形成粗短根和丛生根系。     

水稻僵苗发生的原因及防治

僵苗是水稻分蘖期前后易发生的生理障碍.依据僵苗稻作的发生类型、症状,分析其发生原因,并进行诊断、依症防治.