Growth and establishment of mangrove (Avicennia marina) on the coastlines of Kuwait

Mangrove (Avicennia marina) communities constitute an importantcomponent of the renewable natural vegetation resources of the coastalzones of the Arabian Gulf south of Kuwait. Attempts to introduce themangrove into the intertidal zones of the coastline of Kuwait are underwaybecause of the expected favorable environmental impact of this plant, andbecause of its moderating influence on the local climate and enhancementof the aesthetic and recreational value of the coastlines and fisheryresources. Propagules were collected from natural stands of mangrove inBahrain and the United Arab Emirates. Silvicultural practices were followedto produce healthy plants after growing of propagules in the greenhouse.Observations indicated that there is a positive correlation betweenpropagule weight and the length of the seedling stem. Outplanting wasdone in two sites in the intertidal zone around the Sulabikhat Bay, Kuwait.Data on plant survival showed that the most suitable level for successfulestablishment of mangrove was around or below the 3-meter contour tidalline. After 7 years of growth, plants reached a mean height of 250 cm,which is close to the height of their parent trees in Bahrain. The U.A.E.stock plants reached 288 cm after 5 years of growth in Kuwait. Plantsflowered and produced viable seeds. The biological feasibility ofestablishing mangrove plantations in the intertidal flats of Kuwait's coastlineswas documented from the field observation of the experimental plantations.Studies to document the environmental impact of the introduction areunderway.     

Fungal Communities and Disease Symptoms on Stem Bases of Wheat and Barley and Effects of Seed Treatments Containing Fluquinconazole and Prochloraz

Three successive crops of winter wheat or barley were grown as second, third and fourth cereals. Communities of fungi on shoot bases, identified after isolation on agar media, were more diverse (determined by number of taxa identified) on wheat than on barley, and their diversity increased from year to year. Diversity was not affected by seed treatments containing fluquinconazole or prochloraz. Eyespot (caused by Tapesia spp.) and brown foot rot (caused by Fusarium spp. or Microdochium nivale ) increased from year to year. Eyespot, brown foot rot (after the first year) and sharp eyespot (which remained infrequent), assessed in summer (June), affected wheat more than barley. Eyespot severity was increased slightly on barley by treatments containing fluquinconazole, formulated with or without prochloraz, in the second year (third cereal), when it was also decreased slightly on wheat by fluquinconazole plus prochloraz, except in plots where the treatment had been applied for two successive years. The increases or decreases in eyespot in the second year were accompanied by, respectively, decreases or increases in the frequency of Idriella bolleyi where fluquinconazole was applied alone. Although the eyespot pathogen Tapesia yallundae (but not Tapesia acuformis ) is sensitive to fluquinconazole in vitro , seed treatment, applied principally to control take-all disease, is likely to have only a small effect against eyespot (or other stem-base diseases), and then only on wheat and when formulated with prochloraz.     

梁子湖优势沉水植物冬季种子库的初步研究

初步研究了梁子湖6种优势沉水植物如黄丝草、金鱼藻、菹草、黑藻、苦草和穗状狐尾藻等在冬季的广义种子库（种子、芽苞、断枝等）,包括它们的繁殖特性、种子在小、结构及萌发时的衰减曲线等问题,主要结果为：（1）在梁子湖不同区域内,种子库大小不相同,满江湖、前江大湖、中湖和管理局网围内种子库分别为714.4粒／m^2、107.5粒／m^2、331.9粒／m^2和159.3粒／m^2。种子库的大小受到现实的种群数量、投鱼强度、人类干扰等因素的影响。（2）黄丝草、金鱼藻、菹草种九的种子库占有明显优势,全湖平均分别为198.8粒／m^2、91.7粒／m^2和21.4粒／m^2。（3）每一种植物种群广义种子库的构成和比例具有差异,金鱼藻、菹草、苦草、黑藻四种植物种子库中,无性繁殖体占有主要的地位;黄丝草、穗状狐尾藻两种植物种子库中,种子占有很大的比例,上述六种植物均可用种子和无性繁殖体来产生幼苗,补充到肿群中去。（4）种子库一般存在冬季休眠（菹草为夏眠）,春季种子库萌发,尤其在3月和4月是种子库萌发的高峰期。     

花椒种籽油的含蜡量测定与脱蜡

花椒种籽油的含蜡量测定与脱蜡是长期困扰花椒种籽油处理的一项关键技术,本研究通过分析混合压榨制备的花椒种籽油,花椒籽种壳油及种仁油的含蜡量,研究了5种脱蜡方法脱除花椒籽油中蜡质的脱蜡效果,确定了脱除花椒籽油中蜡质的有效方法,研究结果表明,花椒籽油的含蜡量在15－20％,左右,而这些蜡质基本上都含在种壳油内一即种壳上,种仁油基本不含蜡质,脱除花椒籽油中蜡质的合理方法应是：（1）含蜡量相对较低的精制粗油可选用表面活性剂法脱蜡;（2）当含蜡量相对较高时,为降低脱蜡过程中油的耗损率可选用分步脱蜡法脱蜡;（3）需进行碱炼的油,可在碱炼过程中将蜡质与游离脂肪酸一半除去。     

秦岭田峪河流域种子植物区系研究

田峪河流域是陕西秦岭植物园的核心区,有种子植物128科,605属,1231种（不含种下等级）。区系分析表明,该流域仍以温带成分为主,占总属的70.96%,热带成分占21.13%,地中海与中亚成分占4.41%,中国特有属占3.5%,稀有濒危植物、单种属和少种属、中国特有属及木本植物均占较大比重,说明了历史起源的古老性,地理成分复杂,联系广泛,分布交错,具有明显的温带特征。     

多效抗旱驱鼠剂对田间小麦促长增产效果研究

通过多效抗旱驱鼠剂浸种与拌种的田间试验,对小麦12个生长和产量构成因素进行了测定与多元统计分析。结果表明,RPA浓度是决定促长与增产效果的关键。药剂A的700倍水溶液浸种或30-50倍液拌种对苗期促长作用最好;与对照相比,除B的700倍水溶液浸种处理小麦种子,小麦产量比对照降低2.79%,其它处理均有增产作用,增产率为4.79%-98.67%。其中以药剂A的70倍水溶液拌种和C的600倍液浸种,增产效果最为显著,增产幅度达98.49%-98.67%;对11个影响产量因子的通径分析表明,单位面积的有效穗数是决定产量增长率的首要因素。     

Divergent seed production responses of white and blue flowers of Gentiana leucomelaena (Gentianaceae) to warming and watering

Background: The adaptation, evolution and function of flower colour diversity in response to changing environments are one of the oldest puzzles in plant ecology. It is logical that comparative studies on fitness of flower colour would be the most meaningful if they were conducted on the same genotype.

Aims: We used Gentiana leucomelaena, which produces both white and blue flowers on different tillers of the same individual, as a model species to test adaption and fitness differences of contrasting flowers in contrasting environments.

Methods: We examined seed production by white and blue flowers in response to increased temperatures (28 °C/2 °C vs. 12 °C/2 °C; 12 h light/12 h dark) in a climate chamber study and to watering in the field (+1.5 l m^?2 d^?1 vs. control with no supplementary irrigation).

Results: For white and blue flowers warming decreased but watering increased seed number. Increased temperature and watering increased the size of seeds from white flowers, but neither warming nor watering significantly changed seed size of blue flowers. Seed size was significantly negatively correlated with seed number in the temperature treatments but positively correlated in watering treatments. The positive correlation was strong in white flowers, but the negative correlation was stronger in blue than in white flowers.

Conclusions: Water availability and low temperature confer an advantage to white flowers, while warming and dry habitats favour blue flowers. These divergent responses may influence total plant fitness and thus help explain the adaptive value and evolution of flower colour diversity.     

The life cycle of Anguina agrostis: Development in host plant

Bird A.F. and Stynes B.A. 1981. The life cycle of Anguina agrostis: Development in the host plant. Internationaljournal for Parasitology11: 431–440. The growth and development of the infective second stage “dauer” larvae (DL₂) of Anguina agrostis into adults have been followed under field conditions in rye grass (Lolium rigidum). Three moults were observed to occur during the parasitic phase of development. From the third (second parasitic) moult onwards, there was much more variability in the size of the female nematodes than in the males and sexual dimorphism became very pronounced. The transition from the DL₂ to the second stage parasitic larva (PL₂) is marked by the disappearance of the numerous lipid storage granules which are characteristic of the DL₂, and the development in the PL₂ of an intestine which becomes more pronounced in each succeeding stage, particularly in the adult female. Anguina agrostis is unusual among parasitic nematodes in that the DL₂ has the thickest cuticle of all stages, including adults. The L₄ and adult males have thicker cuticles than the females at the same stages of development. Moulting appears to involve resorption of the innermost basal zone of the shed cuticle as well as morphological and chemical changes to the epicuticle.     

A positive association between oviposition and fruit set: female choice or manipulation?

The relationship between where a female chooses to oviposit and her larvae’s performance at those sites is critical to both the ecology and evolution of plant-insect interactions. For predispersal seed predators that do not themselves pollinate their host and whose larvae are sessile, females must be able to predict which flowers will ultimately be pollinated and set fruit, or be able to manipulate flowers in some way to ensure they set fruit. Otherwise, their offspring will perish. Here we describe the results of an experiment in which we tested if female Hylemya (Diptera: Anthomyiidae) are choosing oviposition sites wisely, or if they are manipulating flowers of their host, Ipomopsis aggregata (Polemoniaceae), in some way to ensure fruit set. Previous work in this system established a positive correlation between oviposition and fruit set. By bagging females on flowers, we removed their ability to choose flowers on which to oviposit. We found that flowers females oviposited on, whether bagged (”no choice”) or unbagged (”female choice”), had a significantly higher probability of setting fruit than ”control” flowers that we bagged but did not cage females on. In addition, we tested if Hylemya prefer particular architectural locations of flowers and if those locations correspond with higher than average fruit set. Although flowers at the distal end of the plant, and those most proximal to the main stem, were more likely to set fruit overall, Hylemya was no more likely to oviposit on those flowers than others on the plant. Taken together, our results suggest that Hylemya is somehow able to manipulate its host to ensure fruit set and thus the provisioning of their larvae. Received: 3 December 1999 / Accepted: 23 March 2000     

The Structure of Detoxin D1

The structure of detoxin D₁, one of the main active principles of detoxio complex, has been established on the basis of the degradative studies and spectral evidences as depicted in formula (I).

Detoxin D₁ has been demonstrated to belong to a new class of the depsipeptide contained an amino acid designated detoxinine which was newly isolated as a natural product.