人工针叶用材林生态系统涵养水源功能的研究

从树冠截留降雨、枯落物持水及土壤蓄水三个方面对辽东山区人工针叶用材林生态系统的涵养水源功能进行了定量研究。结果表明:各人工针叶用材林生态系统树冠的截流率为18.3%~28.5%;枯落物贮量为10.1~19.4 t.hm-2,枯落物最大持水量取决于枯落物贮量及其最大持水率,最大持水率为自身干重的1.5~2.5倍;0~40 cm土层的土壤蓄水量为840~1520 t.hm-2。综合分析表明:6种人工针叶用材林的涵养水源功能主要决定于土壤蓄水量,树冠截留雨水和枯落物持水起辅助和调节作用,其中,长白落叶松林的涵养水源功能最强,其次是华山松林、日本落叶松林、红松林、油松林,而云杉林的涵养水源功能相对最弱。     

人工巢箱招引杂色山雀研究

2005年3-7月于辽宁省白石砬子国家级自然保护区悬挂人工巢箱招引杂色山雀,共设置80个巢箱,其中11个巢箱被4种鸟利用。鸟类的进驻率为13.75%,其中杂色山雀利用了8个巢箱,利用率占招引总数的72.73%。对招引到杂色山雀的巢箱因素进行分析,结果表明:杂色山雀多选择2m以上、南坡中下部、巢口朝西南的巢箱,而巢箱悬挂的树种对其选择没有影响,人为或天敌干扰会导致杂色山雀放弃巢箱。该项试验为进一步保护稀有物种和研究其繁殖生态提供了初步的依据。     

退化人工梭梭林的恢复技术研究

对退化人工梭梭林进行恢复试验研究发现:滴灌可使梭梭林地土壤含水率显著提高;梭梭光合作用增强;群落物种数增多,盖度增大;防风固沙作用增强.布设机械沙障可使退化梭梭林地表粗糙度增大,林内近地面层风速、输沙量显著下降.春灌3 a后,不仅退化梭梭个体恢复正常生长,同时梭梭林群落物种组成数明显增加,盖度显著增大,生态功能也逐渐恢复.雨水集流和雨水下渗改造两种模式应用1～2 a后,退化梭梭林地土壤含水率均有明显提高.滴灌、布设机械沙障、春灌和改造结皮4种技术措施对退化梭梭林生长及其环境均有明显的恢复作用,其中滴灌、机械沙障恢复技术是当前和今后推广的主要措施;春灌和改造结皮可作为前两种技术的补充措施.     

Configuration and development of root systems of cuttings and seedlings of Eucalyptus globulus

Stem cuttings of Eucalyptus globulus are used within tree improvement programs and for mass deployment. To be successful, cuttings must perform as well or better than seedlings. The root systems of cuttings are fundamentally different from those of seedlings. If these differences influence growth, the differences and their consequences must be identified and the propagation system manipulated to improve performance of the propagules.Cuttings are only a viable alternative to seedlings as planting stock if the method of propagation does not affect their growth and development adversely. Full-sibling cuttings and seedlings of Eucalyptus globulus were compared under controlled environmental conditions to minimise extraneous sources of variation, and to establish whether changes in growth or development were induced by propagation. On three occasions over a period of eight weeks root-collar diameter, shoot height, leaf and stem weight, shoot/root ratios and root system morphology were measured on cuttings and seedlings. Seedlings were taller than cuttings throughout the experiment, but both plant types had similar height growth rates. Diameter growth rates were lower in cuttings than seedlings, and there were differences in both height and diameter growth rates between families. Root system configuration differed between the plant types. Seedlings had strongly gravitropic tap-roots, with two types of primary roots from which secondary roots emerged. Cuttings had no tap roots, and the main structural components of their root systems were adventitious roots formed during propagation. Cuttings did not develop further structural roots during the experiment, whereas seedlings continued to develop primary roots. Individual primary roots of cuttings were longer and had larger mid-point diameters than those of seedlings, but the total length of primary roots was greater in seedlings. Seedlings also had a greater number and total length of secondary roots. Shoot/root ratios, calculated from a range of functional measures, were higher in cuttings than seedlings.     

葡萄酒人工催陈技术

陈酿是葡萄酒生产过程中的一个重要环节,但是自然陈酿过程缓慢,造成葡萄酒生产和上市周期过长。为了缩短陈酿时间,葡萄酒生产企业日益重视人工催陈技术的研究与应用。介绍了几种人工催陈方法,并对各方法的催陈机理进行了系统地阐述,对各方法的催陈效果进行了综合评价,最后确定适合葡萄酒生产的人工催陈技术。     

Slash pine (Pinus elliottii Engelm.) somatic embryogenesis II. Maturation of somatic embryos and plant regeneration

Maturation of slash pine (Pinus elliottii Engelm.) somatic embryos was achieved using two protocols, each starting with a different agar incubation step to deplete plant growth regulators (PGRs) used in previous cultural steps. Strength of maturation medium (single vs. double) was found important in the first protocol to develop normal, mature embryos. In the second protocol, abscisic acid (ABA) concentrations (0, 15 and 30 M) and carbohydrate sources were tested for embryo maturation. Thirty M ABA and 6% maltose were deemed the best combination. Embryo germination was accomplished in a continuously lighted environment and embryos receiving a cold pretreatment (4 °C in darkness for 16 days) germinated better than embryos which did not receive cold pretreatment. With a survival rate of 33% after acclimation in a mist system, more than 25 plants from somatic embryos have been established in a greenhouse. Incompletely germinated embryos (lacking roots) were rooted via adventitious rooting techniques and subsequently established in the greenhouse. All established plants obtained from somatic embryogenesis appear normal in morphology.     

Root distribution ofDactyladenia (Acioa) barteri andSenna (Cassia) siamea in alley cropping on Ultisol. I. Implication for field experimentation

Root observations were carried out on a typic Paleudult in the humid forest zone of south eastern Nigeria in an alley cropping trial usingDactyladenia (Acioa) barteri andSenna (Cassia) siamea as hedgerow trees and the interrow space planted to maize/cassava intercrop. Rooting depth ofD. barteri andS. siamea exceeded 1.6 m. Lateral root propagation ofS. siamea was 15 m, and ofD. barteri was 5 m from the hedgerows. The whole no-tree control plot was within the range of roots of the adjacent hedgerows. Rooting density and depth ofS. siamea in the no-tree control plot was generally higher than of cassava.S. siamea and cassava root density were inversely correlated. Assuming radial symmetry of root propagation, water and nutrients were available from an area 6.1 and 2.3 times larger than the allocated plot size ofS. siamea andD. barteri, respectively. Data obtained in alley cropping trials, not considering lateral root propagation, can be invalidated through exploitation of the no-tree control treatment and nutrient acquisition by hedgerow species from a larger area than allocated, thus underestimating and overestimating the performances of the respective treatments. Possible alternative measures for avoiding root interference are discussed but no good solution can be given.     

马尾松毛虫有虫面积预测模型的研究

运用人工神经网络的原理和方法 ,根据相关系数法选取与台州市 7个县 (市、区 )马尾松毛虫有虫面积相关关系都比较密切的 14个气象因子 ,然后进行主成分分析 ,在此基础上 ,将前 6个主成分的主坐标值作为样本的输入特征 ,建立以 7个县 (市、区 )马尾松毛虫有虫面积为期望输出的BP网络预测模型 ,结果表明 :所建立的BP模型 ,具有令人满意的拟合精度和预测精度。当隐含层神经元个数为 4个时 ,7个县 (市、区 ) 3组预留有虫面积 3a预测结果的卡方检验为 :η=7.2 92 0 相似文献   

干旱半干旱地区人工牧草节水灌溉技术研究进展

对干旱半干旱地区人工牧草节水灌溉技术的研究状况进行了回顾和总结，并提出了今后西部干旱半干旱地区人工牧草节水灌溉技术研究的重点内容与方向。     

优良保健树大叶冬青组培扩繁的研究

以大叶冬青具节茎段芽体增殖产生试管苗,适宜培养基为MS 1．Oμmol NAA 8．8μmol BA或MS 1．0μmol NAA 9．1μmolZT;幼叶外植体诱导的愈伤组织块转培于WPM 5．Oμmol TDZ 3.Oμmol IAA培养基上,能产生较多不定芽苗(每一愈伤组织块平均产生11．2株);BA对大叶冬青外植体不定芽的处理能产生较好的增殖系数与高生长;试管苗适宜生根处理为：1／4KS 1．Oμmol NAA(或 1．Oμmol IBA);室外移栽成活率达90％。