应用热扩散式探针法对南方红壤丘陵区湿地松人工林耗水量的研究

运用Granier热扩散式探针法对湿地松(Pinus elliottii)树干液流密度进行长期连续测定,并对其周围多个气象要素和土壤要素进行同步测定。湿地松生长旺季不同月份晴天液流密度日变化规律基本一致,但液流启动、到达峰值的时间以及开始升高、开始下降的时间间隔存在差异。样木解析结果表明,处于低龄期的湿地松,整个木质部都可看作边材,边材面积和胸径可用二次函数很好地拟合。方差分析结果表明:不同胸径湿地松树干液流密度不存在显著性差异,与胸径无紧密关系。回归分析结果表明:湿地松日累计液流量与边材面积呈显著的线性相关关系,相关关系的判定系数达0.99。另外,单位边材面积日累计液流量与入选各气象因素的相关性显著,相关程度大小顺序为光合有效辐射>冠层相对湿度>冠层温度。结合边材面积-胸径回归方程和样木胸径调查资料,分别采用2种方法推算整个标准地的耗水量。经比较,2种方法所得结果差别不大,各自适用于一定的范围。     

质量平衡法估测树干呼吸的理论与应用

介绍质量平衡法的理论、估测方法及其应用,并对其进行评价.质量平衡理论认为:一段树干组织产生的CO2,应该是CO2通量的总和,包括通过树皮向外扩散的CO2释放通量、该段树干液流中的CO2运输通量(流入和流出液流的CO2浓度之差)及液流中的CO2储存通量(液流中CO2浓度在时间上的变化量).应用质量平衡法测定树干呼吸的关键是要估测树干内部的CO2通量,即液流中CO2的储存、运输和扩散.对于液流中CO2的估测主要有2种方法:1)用仪器直接测定木质部液流中的CO2浓度;2)通过测定树干液流停止流动或相对很低时(夜间)树干的CO2释放通量与液流流动时(白天)树干CO2释放通量的差值,间接估测木质部液流中CO2浓度.质量平衡方法提供了一个更为精确地估测木本组织呼吸的方法,其结果更为合理.     

石榴溃疡病害病原学研究

对石榴溃疡病害3菌株所引起的病害症状、病原菌的形态学特征、培养学特性、生理学特性及分子遗传多样性等方面进行比较研究.结果表明:石榴疮痂病与石榴果实上增生型症状的病原菌具有更近的亲缘关系,应为同一病原菌引起,推测该病原菌首先侵染石榴侵染枝干,然后侵染石榴的花萼和果实;而石榴干腐病病原菌主要侵染枝干,是否侵染果实及引起症状特征需要继续进行研究和鉴定.     

申嗪霉素对油菜菌核病菌生物学活性的初步研究

申嗪霉素是一种新型微生物源杀菌剂,主要成分为吩嗪-1-羧酸。测定了申嗪霉素对油菜菌核病菌菌丝生长的抑制作用。结果表明,申嗪霉素对油菜菌核病菌51个菌株菌丝生长的平均有效抑制中浓度(EC50值)为3.31±0.77 μ g/mL,并且与常规杀菌剂多菌灵、菌核净无交互抗性关系。离体叶片和田间药效试验表明,申嗪霉素对油菜菌核病的防治效果随其处理剂量增加而提高,用有效成分200 μ g/mL药液处理时,抑制离体叶片发病的效果可达到67.08%,田间防效可达83.29％,优于对照药剂异菌脲。     

叶面损伤对茎瘤芥主要经济性状的影响研究

研究返青成活期、瘤茎膨大始期和盛期茎瘤芥叶片受损对其主要经济性状的影响,结果表明:在试验范围内,叶面损伤对茎瘤芥瘤茎形状、茎瘤芥产量、植株大小等有影响且规律性明显;叶片受损程度越大,受损时间越迟,影响越大。完全展开的叶片受损后对茎瘤芥主要经济性状的影响要低于未完全展开的叶片,完全展开叶全部受损后,未完全展开叶再受损影响更大,而且随着叶片受损程度的加重和时间的推迟影响增大。     

A nested‐PCR method for rapid detection of Sclerotinia sclerotiorum on petals of oilseed rape (Brassica napus)

This study established a quick and accurate method to detect petal infection of oilseed rape (Brassica napus) by Sclerotinia sclerotiorum using a nested‐PCR technique. DNA samples were extracted from each petal using a microwave method, followed by two rounds of PCR amplification. The first‐round PCR amplification was performed using the universal fungal primer pair ITS4/ITS5, and the second‐round amplification with a specific primer pair XJJ21/XJJ222, which was designed using the single‐nucleotide polymorphisms among nuclear rDNA ITS sequences of Sclerotinia spp., Botrytis spp. and other selected fungi. The established technique is rapid and inexpensive, and has a high degree of specificity and sensitivity. This assay can distinguish Sclerotinia spp. from other fungi, including Botrytis cinerea, a closely related and frequent cohabitant on oilseed rape petals, and can detect 50 fg genomic DNA, five ascospores of S. sclerotiorumin vitro or 50 ascospores of S. sclerotiorum on one petal in approximately 6 h, even in the presence of a high background of oilseed rape DNA. This technique was successfully applied in detecting natural petal infections.     

大青山主要林型林分密度与竞争关系的研究

采取克拉夫特分级法d=r/的公式(r:林木胸径,R:林分平均胸径),进行Ⅰ-Ⅴ级木分类,以大青山油松人工林、落叶松人工林和白桦天然次生林为主要研究对象,对比分析不同密度下林木分级、竞争和径阶的变化情况,为大青山植树造林提供相对适宜的密度区间。结果表明:大青山油松人工林密度不宜超过3200株/hm2,落叶松在1700株/hm2时林木分化现象并不明显。白桦天然次生林因萌生起源、年龄因素的影响,密度对其分级木影响效应不显著。     

Effects of Vegetation Stems on Hydraulics of Overland Flow Under Varying Water Discharges

Vegetation plays an important role in soil erosion control, but few studies have been performed to quantify the effects of vegetation stems on hydraulics of overland flow. Laboratory flume experiments were conducted to investigate the potential effects of vegetation stems on Reynolds number, Froude number, flow velocity and hydraulic resistance of silt‐laden overland flow. Cylinders with diameter D of 2·0, 3·2 and 4·0 × 10⁻² m were glued onto the flume bed to simulate the vegetation stems, and a bare slope was used as control. The flow discharge varied from 0·5 to 1·5 × 10⁻³ m³ s⁻¹ and slope gradient was 9°. Results showed that Reynolds number on vegetated slope was significantly higher than that on bare slope because of the effect of vegetation stems on effective flow width. All the flows were supercritical flow, but Froude number decreased as D increased, implying a decrease in runoff ability to carry sediment. The mean flow velocity also decreased with D, while the velocity profile became steeper, and no significant differences were found in surface flow velocities among longitudinal sections on all slopes. Darcy–Weisbach friction coefficient increased with D, implying that the energy consumption of overland flow on hydraulic resistance increased. Reynolds number was not a unique predictor of hydraulic roughness on vegetated slopes. The total resistance on vegetated slopes was partitioned into grain resistance and vegetation resistance, and vegetation resistance accounted for almost 80% of the total resistance and was the dominant roughness element. Further studies are needed to extend and apply the insights obtained under controlled conditions to actual overland flow conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

矮牵牛茎段植株再生体系的建立

将矮牵牛Petunia hybrida Vilm的茎段接种在MS附加不同激素的培养基上进行愈伤组织诱导.结果表明:在MS BA1.0 mol.L-1 NAA1.0 mol.L-1的培养基上可以形成愈伤组织,而且经过继代培养仍可形成愈伤组织;茎段或愈伤组织接种在MS BA1.0 mol.L-1 NAA0.1 mol.L-1的培养基上可以形成不定芽,且诱导率达100%;健壮的高1.5~2.0 cm的不定芽接种在1/2MS IBA0.5 mol.L-1 AC1.0 g.L-1的培养基上,其生长根状况良好,生根率达100%.     

单株立木材积测定方法的研究

单株立木材积的测定对林业生产和科学研究工作有着重要的作用,主要的测定方法是通过胸径、树高、上部直径或上部直径的高度来计算干形指数,然后计算单株立木材积。而不同的方法所用上部直径不同。本文用5个树种的解析木,分别对较常见的5种测定方法的测定精度进行了研究。得出的结论为:3/4形点法、0 5形点法、胸高形率法精度较高,绝对形率法、望高法精度较低。建议对干形饱满的树种采用3/4形点法、0 5形点法;对干形尖削的树种采用0 5形点法、胸高形率法。