提高裸根植苗造林成活率探讨

从掌握造林基本要点、积累栽树窍门、加强后期林地管护3个方面介绍了提高裸根植苗造林成活率的经验。     

提高良种龙眼嫁接成活率的试验研究

以广东龙眼主栽品种：大乌圆、储良、大果、双孖木、石硖为试材，分别用不同方法、不同时期、不同砧穗组合进行嫁接多项研究，结果表明：单芽切接的成活率最高，达到75％以上，在不同季节的嫁接实验中，春末夏初(3-5月)是最合适的嫁接季节；在以大乌圆为砧木的嫁接实验中，分别采用储良、大乌圆、大果、双孖木、石硖为接穗，采用单芽切接的嫁接方法，发现双孖木为接穗的嫁接成活率最高，达55．9％．     

光周期条件对罗氏沼虾幼体存活率及体长生长率的影响

用４Ｌ：２０Ｄ、８Ｌ；１６Ｄ；１２Ｌ；１２Ｄ和２４Ｌ：０Ｄ四种光周期条件培养罗氏沼虾骚状幼体，观察其存活率和生长、发育情况。研究结果表明，随着光照时间的延长，特别是在连续照明的条件下，与最短的光照条件相比，幼体的存活率及体长生长率分别提高１５７．７％和２．２％ｄ，而育成Ｐ１的时间却相应缩短了１０ｄ。     

MOMENT-METHOD ESTIMATION BASED ON CENSORED SAMPLE

In reliability theory and survival analysis, the problem of point estimation based on the censored sample has been discussed in many literatures. However, most of them are focused on MLE, BLUE etc; little work has been done on the moment-method estimation in censoring case. To make the method of moment estimation systematic and unifiable, in this paper, the moment-method estimators(abbr. MEs) and modified momentmethod estimators(abbr. MMEs) of the parameters based on type Ⅰ and type Ⅱ censored samples are put forward involving mean residual lifetime. The strong consistency and other properties are proved. To be worth mentioning, in the exponential distribution,the proposed moment-method estimators are exactly MLEs. By a simulation study, in the view point of bias and mean square of error, we show that the MEs and MMEs are better than MLEs and the “pseudo complete sample” technique introduced in Whitten et al.(1988). And the superiority of the MEs is especially conspicuous, when the sample is heavily censored.     

四川冶勒自然保护区垂枝香柏年龄结构研究

调查分析了四川省冶勒自然保护区内垂枝香柏的年龄结构.编制了静态生命表;绘制了存活曲线、死亡率曲线和消失率曲线;并探讨了垂枝香柏的更新.结果表明：①该树种平均年龄较大,约为277年.②存活曲线处于Deevey-Ⅱ型和Deevey-Ⅲ型之间,死亡率与消失率变化趋势一致.种群生存率呈单调下降趋势,生存率下降趋势前期相对稳定,中期逐渐增大,后期又趋向于稳定,说明垂枝香柏种群相对稳定,并有一定的更新能力.③保护区内垂枝香柏整个生长期中,200年以前,死亡率变化相对平缓,200年以后,死亡率急剧上升,在320年～44     

具有Beddington-Deangelis类功能反应的时滞食物链系统全局吸引性研究

研究了具有Beddington-Deangelis类功能反应的时滞食物链捕食者-食饵系统模型,得到了与时滞有关的系统永久持续生存的充分条件,同时通过构造Lyapunov函数得到了与时滞有关的系统全局渐近稳定的充分条件,是对文献结果的进一步推广和改进.     

盐度对龙虾叶状幼体发育和存活的影响

多个梯度多个重复的对比试验结果表明龙虾（Ｐａｎｕｌｉｒｕｓ）叶状幼体要求的海水的适宜盐度为３４‰－３５‰。投入金藻（Ｄｉｃｒａｔｅｒｉａｓｐ．）扁藻（Ｐｌａｔｙｍｏｎａｓ ｓｐ．）和光合细菌于水体中，养活作为龙虾叶状幼体饵料的丰年虫（Ａｒｔｅｍｉａ ｓａｌｉｎａ）幼体，可减少换水量，保持养殖水体的盐度稳定。３４‰－３５‰盐度的养殖水体能有效地抑制某些病原体的入侵。     

不同日龄的桔小实蝇成虫饥渴耐受能力的初步研究

通过不同给食、给水的处理方式对桔小实蝇Bactrocera dorsalis（Hendel）不同日龄的雌雄成虫进行了饥渴耐受能力的测定。以平均存活时间作为桔小实蝇饥渴耐受能力的指标。结果表明：在给水缺食的情况下，25℃时，桔小实蝇不同日龄成虫的平均存活时间介于2．2～3．9d，15℃时，介于6．2—9．4d；在给食缺水情况下，25℃时，不同日龄成虫平均存活时间介于3．1—5．3d，而15℃时，介于5．8～10．7d；在缺食缺水情况下，25℃和15℃时，其平均存活时间分别介于2．0～3．6d和5．3—8．0d。在25℃条件下，各日龄的桔小实蝇雌、雄成虫耐渴的能力要强于耐饥能力，且食物的存在能显著延长桔小实蝇的平均存活时间；在15℃条件下，除了10日龄和15日龄的雄虫外，其他日龄雌（或雄）虫的耐饥能力与耐渴能力间并无差异，而水或食物哪样更能显著延缓桔小实蝇成虫的死亡，还与成虫日龄和性别有关；25℃时，15日龄雌雄成虫间以及15℃时，5日龄及10日龄的雌雄成虫问的平均存活时间均在给食缺水时出现显著差异；在相同的处理方式下，15℃时成虫的饥渴耐受能力比25℃时的强。     

南方鲇皮肤,唇瓣和须结构的研究

应用扫描电镜和组织学方法研究南方鲇皮肤、唇瓣和须的结构．结果表明，体表不同部位皮肤的厚薄不一，但基本结构相似．唇瓣的前、后口腔面在覆盖物、表面凹陷、味蕾分布、腺细胞组成上有差异．须侧扁，由表皮、真皮、软骨、血管和神经组成．皮肤、唇瓣和须的分泌细胞主要有杯状细胞、棒状细胞、颗粒细胞和浆液细胞，以棒状细胞尤为丰富．味蕾和分泌细胞的大小、形态、分布频率、存在部位不同．皮肤上还具丰富的侧线孔、小窝器官、Ｍｅｒｋｅｌｓ感觉器官等．探讨了皮肤、唇瓣和须的结构与功能关系     

Not every drought is bad: quantifying reproductive effort in the harlequin frog Atelopus laetissimus (Anura: Bufonidae)

Atelopus laetissimus is an endemic and threatened harlequin frog from the high mountain forests of Sierra Nevada de Santa Marta, Colombia. Knowledge of its reproductive biology is essential for understanding the intraspecific interactions that can help the conservation of Atelopus species. We quantified the energy, measured in body weight, invested by males and females of A. laetissimus for reproduction, and how this energetic investment is related to the survival of individuals and rainfall conditions in habitats during two years (2014 and 2015). Our results show plasticity in terms of reproductive phenology linked to rainfall with short- and long-duration breeding strategies. The first year of this study, 2014, had a precipitation level in accordance with the annual averages at the area. During this time frogs exhibit a short breeding period. Contrary to 2014, 2015 was a year with little precipitation, below the annual averages, which probably facilitated the females’ quick spawning in the creeks and a consequent reduction in the duration of amplexus and low breeding efforts by males. This, in turn, was related to a long breeding period that favors the survival and reproduction of males during the entire year. In 2014 we found a decrease of 25% to 30% body weight of potentially reproductive males, which may be attributed to a prolonged duration of amplectant events.