Soft X-ray observation of water distribution in the stem ofCryptomeria japonica D. Don II: Types found in wet-area distribution patterns in transverse sections of the stem

Using soft X-ray photography, two-dimensional observations were made of the water distribution within the green stem ofCryptomeria japonica D. Don. Variations in the distribution pattern of the wet area in the horizontal plane of the lower stem were described. The distribution patterns showed extreme variation among individual trees, with broad wet-area distribution types appearing, namely, the regularly distributed wet area and the irregularly distributed wet area. We defined five basic types of wet-area distribution patterns on the basis of their regularity or irregularity. It was concluded that the between-tree variation in the wet-area distribution causes the between-tree variation in the mean moisture content of the heartwood. The distribution patterns of the wet area were similar for individual trees within each plus-tree clone.Part of this paper was presented at 46th annual meeting of the Japan Wood Research Society at Kumamoto, April 1996     

棚室番茄水肥一体化试验

为对水肥一体化在生产上的应用提供数据支持,在河北永年县开展了棚室番茄水肥一体化技术与常规普通施肥对比试验。试验结果表明,采用每667 m2用水250 m3、追肥40 kg的水肥一体化技术,可比常规栽培节水34.2%、节肥20%,番茄增产4.74%。     

水分和氮素胁迫对辣椒产量形成及抗逆性评价

通过探索水分胁迫和氮素胁迫条件对辣椒产量及相关性状变化的影响,以期为土壤瘠薄地区辣椒水肥效应的合理应用和抗旱耐瘠型辣椒新品种选育提供依据。试验结果表明,水分和氮素之间存在互作效应,氮素具有增强抗旱性的作用,在水分和氮素胁迫下辣椒产量明显下降;H089和H089×H042025D为抗旱耐瘠型材料,花溪辣椒、H042025D和遵义朝天椒为中抗旱耐瘠型材料、DF-1和HP-1为弱抗旱耐瘠型材料。     

Sedimentation associated with forest road surfacing in a bottomland hardwood ecosystem

Access systems are a necessary element of resource production in bottomland hardwood sites. However, road building may have a detrimental effect on hydrologic function of the site. This report describes initial results of a study designed to examine the effect of different road surfacing treatments on water quality.

Four surfacing treatments installed on two test roads included native soil, native soil with vegetative stabilization, 6 cm of gravel, and 15 cm of gravel over geotextile. During the first flooding season periodic sampling measured floodwater suspended sediments and location of erosion and sediment deposition within the road prism. Initial results suggest that sediment movement was confined to the road right-of-way, with no statistically significant sedimentation effects detected beyond the clearing limits of the road. The study is continuing for another field season.     

Effect of water potential on fruit body formation ofLentinula edodes in sawdust-based substrate

The influence of substrate water potential () on the growth and fruiting of three genotypes of shiitake (Lentinula edodes) was investigated. A slight reduction of (–0.5MPa) stimulated mycelial and colony growth on liquid, agar, and sawdust-based substrates.L. edodes has been found to grow well at a around –0.5 MPa, which corresponds to a moisture content around 55%. A small decrease in at the final vegetative growth phase had positive effects on flush quantity. The substrate was significantly affected by the interaction between genotypes and spawn run time. The of well-colonized mature substrate was –0.7MPa before and –4.OMPa after the fruiting. The rose again to –0.7MPa during rapid absorbance of water by soaking, and this rise was repeated during the second and third flushes. It is suggested that the water-holding capacity of a substrate is related to culture maturity. Excellent water-providing capacity (higher) is expected in the substrate of well-matured cultures with a high density of mycelial colonization.Part of this paper was presented at the 46th annual meeting of the Japan Wood Research Society, Kumamoto, April 1996     

鄱阳湖水位特征与湿地生态保护

从分析江湖关系入手，研究鄱阳湖的水位及湿地生态特征，并提出人工控湖等加强湿地生态保护的对策建议。     

新防腐剂TWP橡胶木防腐试验

TWP防腐剂对木腐菌的毒性剂量为2.2—3.2kg/m~3,毒杀双钩异翅长蠹初龄幼虫的剂量为1.0kg/m~3,抑制蓝变菌和霉菌的毒性浓度分别为1％及1.5—2.0％,对雄性小鼠口服半致死剂量(LD_(50))为1301mg/kg,使用时对人、畜和环境比较安全,并保持木材原有色泽。生产性应用试验结果表明,橡胶木生材用2.0—2.5％TWP,满细胞法或振荡加压法处理,净药保持量4±0.7kg/m~3,防腐效果相当干硼酚合剂12kg/m~3,并优于进口防腐剂。     

洞庭湖滩地造林成活率的关键影响因子

用样行法对洞庭湖滩地新造速生丰产纸浆林的成活率进行调查,同时了解造林地连续4 a汛期的水文规律和海拔高程的演变过程,通过分析造林成活率与主要影响因子之间的关系,发现淹水时间为滩地造林的限制性因子,营造速生丰产林、一般用材林和短周期工业原料林时,造林地年淹水天数依次不能超过19、35和62 d;苗木等级对造林成活率有重大影响,特级苗、Ⅰ级苗、Ⅱ级苗、Ⅲ级苗的平均成活率在海拔低于32 m的造林地上分别为68.8%、49.3%、18.7%、2.4%,在海拔超过32 m的造林地上分别为98.8%、79.6%、36.4%、14.7%;采用开沟抬垄整地可减轻涝渍胁迫,从而大幅度提高造林成活率.     

拉市海越冬末期斑头雁行为的初步研究

2004年2月18日～3月14对在拉市海越冬斑头雁的行为进行了研究，采用瞬时扫描方法进行行为取样，并对其在越冬地的行为进行观察记录。结果表明：斑头雁通常是早上7：30后飞离夜栖地，傍晚19：30以后从主要活动地飞回夜栖地。观察后期(3月7～13日)与观察前期(2月18～25日)相比，其飞离夜栖地的时间提前约20分钟，而从觅食地飞回夜栖地的时间则要晚10～25分钟。斑头雁无论取食还是夜栖，都喜集群，通常还有其他鸟类与斑头雁混群，如赤麻鸭等。3月初，有部分斑头雁开始北迁，大部分北迁是在3月中旬。越冬末期斑头雁行为时间的分配率为取食35．01％、静栖34．95％、警戒13．88％、运动8．35％、理羽6．77％、饮水0．63％、社群行为0．41％，所占比例依次减少。经对斑头雁在陆地和水域生境中的行为样本分别进行计算，表明斑头雁在这两种生境中有不同的行为时间分配模式。在陆地里，斑头雁的主要行为是取食(约占47％)，而在水域中，斑头雁的主要行为是静栖(约占46％)，表明斑头雁的食物主要是从陆地中获取。在一天中，斑头雁的不同行为出现的高峰时间不同，取食高峰时间和警戒高峰时间在早上9：00至10：00和傍晚17：30～19：15；静栖高峰时间在14：00～17：00；运动高峰时间在10：30～12：30；理羽高峰时间在14：30～17：00。     

杨树无性系幼苗光合作用和PV水分参数对水分胁迫的响应

比较研究了不同水分条件下杨树2个无性系幼苗的生长、光合特性和多种水分参数等，探讨其对水分胁迫的适应机制。结果表明，水分胁迫下2个无性系幼苗的生长减慢．净光合速率降低，昭林杨6号受水分胁迫影响较小，欧美杨64号受水分胁迫影响较大。胁迫初期，2个无性系光合作用受气孔限制，胁迫后期及复水后的恢复期，光合作用受非气孔限制。胁迫时杨树呼吸速率降低，尤其是昭林杨6号，以保持碳平衡。胁迫时2个无性系的ψs^100、ψs^0、ROWC^0均降低，ψs^100与ψs^0差值增大，表明杨树可以通过渗透调节维持压力势，对水分胁迫作出适应性反应，与欧美杨64号相比昭林杨6号这种能力更强，表明其抗旱性强。