温度对莲雾耐藏性及品质的影响

研究了温度与莲雾在贮藏过程中的外观变化及其生理指标变化的关系.结果表明:莲雾果实在室温(25℃～33℃)下的贮藏寿命为4d.低温(10℃)贮藏能够降低莲雾果实的水分散失,减缓果实中维生素C和花青素含量的下降,抑制其呼吸速率,维持果实细胞膜的完整性,使莲雾的贮藏寿命延长了8d.     

莲雾SRAP反应体系的优化及其应用

以莲雾DNA为模板,应用正交设计法对SRAP反应体系中的各个主要影响因素进行了优化筛选。结果表明,20 μL反应体系中各组分的最适浓度或用量分别为：1×Buffer,3.0 mmol/L Mg2+,0.3 mmol/L dNTPs,0.4 μmol/L引物,0.5 U Taq DNA聚合酶和40 ng模板DNA。利用该优化体系通过64对SRAP引物组合对7份连雾进行了SRAP-PCR扩增,证实了该体系具有稳定可靠、重复性好、多态性较强等特点。     

北京松山不同密度丁香天然林枯落物及土壤水文效应

以北京松山5个不同密度（784,1 024,1 210,1 616,1 872株/hm²）的丁香（Syzygium aromaticum）天然林为对象,对其枯落物层及土壤层水文效应进行研究。结果表明:枯落物总蓄积量、最大持水率、最大持水量随丁香天然林密度的升高而增大。枯落物的总储量在13.19～31.66 t/hm²之间;有效拦蓄能力在32.71～79.77 t/hm²之间;枯落物最大持水量在50.76～119.29 t/hm²之间,与浸泡时间呈明显的对数关系（R > 0.86）;枯落物最大持水率为385.72%～507.16%,枯落物吸水速率与浸泡时间呈明显的幂函数关系（R > 0.99）;同一密度土壤容重随土层深度的增加而增大,总孔隙度随密度的升高先增大后减小。初渗速率在37.50～54.55 mm/min之间,入渗速率与入渗时间存在较好的幂函数关系（R > 0.99）。中密度丁香天然林水源涵养功能较强。     

不同激素处理对丁香扦插生根的影响

采用IBA,ABT,NAA对丁香插穗进行处理,分析不同激素对丁香扦插生根特性的影响。结果表明,IBA处理硬枝插穗生根特性效果最佳,生根率最大值达到了84.63%;NAA处理嫩枝插穗生根效果最好,生根率最大值达93.32%。       

海南杜鹃热诱导基因RhRCA1启动子的克隆与功能分析

为了阐述RhRCA1基因的调控机制,以海南杜鹃(Rhododendron hainanense)3年生扦插苗为材料,分析RhRCA1高温响应和组织表达特性;并克隆获得RhRCA1的启动子序列,将该启动子分别驱动荧光素酶报告基因在烟草中瞬时表达、GUS报告基因在拟南芥中稳定表达,分析该启动子活性、组织特异性和热诱导性。结果显示:(1)25℃条件下,RhRCA1表达量极低,37℃处理后其表达量显著升高,呈现典型的热诱导特性,并且RhRCA1在绿色组织中的表达量显著高于非绿色组织,呈现组织特异性;(2)获得的启动子长1624 bp,其含有多个非生物胁迫响应、光响应、组织特异性等相关元件;(3)构建RhRCA1启动子和萤光素酶融合的植物表达载体,在烟草叶片中瞬时表达,荧光成像结果表明RhRCA1启动子能强烈响应高温胁迫;(4)构建RhRCA1启动子和GUS融合的植物表达载体,转化拟南芥植株筛选至T3代,GUS染色结果显示,高温能显著诱导RhRCA1启动子在拟南芥子叶、成熟叶、茎、萼片、果荚等绿色组织中的表达。研究结果表明RhRCA1启动子是1个兼具高温诱导型和组织特异性的启动子,可应用于植物抗逆基因工程,提高植物在高温胁迫下的抗性。     

莲雾ISSR反应体系的优化与应用

以黑珍珠莲雾为试材,对ISSR反应体系中的各个主要影响因子进行了优化筛选,结果表明,25μL ISSR反 应体系各组分的最适浓度分别为:1×Buffer(不含Mg2+)、2.0 mmol/L Mg2+、0.2 mmol/L dNTPs、Taq DNA聚合酶1.5 U、引 物0.2 μmol/L、模板1.0 ng/μL。此外,加入1.6％的甲酰胺有利于减轻背景噪音的干扰。并利用该优化体系对12个连 雾类型和2个近缘种进行了ISSR扩增,证实了该体系稳定可靠。     

进境莲雾果实软腐病的调查与鉴定

从旅客携带进境的莲雾果实上检获软腐病,对该病进行了较详细的调查与鉴定,确定其病原菌为Ｐｅｓｔａｌｏｔｉｏｐｓｉｓ ｇｕｅｐｉｎｉｉ（Ｄｅｓｍ．）Ｓｔｅｙ。迄今为止,该病尚未见报道。     

Evaluation of different agroforestry tree species for their suitability in the phytoremediation of seleniferous soils

Seven agroforestry tree species were grown in a clay loam soil treated with different levels of selenate‐Se, viz. 0, 1.25, 2.5 and 5.0 mg/kg supplied through sodium selenate. After 1 year of growth, a progressive decrease in dry matter of leaves, stem and roots was observed with increasing levels of applied Se. However, a significant decrease in dry matter yield was observed only at or above 2.5 mg Se per kg soil and shisham (Dalbergia sissoo) proved to be highly sensitive to the presence of selenate‐Se in the soil. On average, the largest above‐ground and below‐ground biomass was accumulated by arjun (Terminalia arjuna) and the lowest by the acacia tree (Acacia tortillas). The selenium content of leaves, stem and roots of all the tree species increased significantly with increasing levels of applied Se, although a large variation within species was observed. In the stem portion of different trees, the highest concentration of Se was found in dek (Melia azedarach) (5.1 mg/kg) and the lowest in mulberry (Morus alba) (2.6 mg/kg). The efficiency of selenium removal (including leaves, stem and roots) was the highest in arjun followed by eucalyptus (Eucalyptus hybrid) – Clone 10, mulberry, jambolin (Syzygium cumini), dek, shisham and acacia. Effective removal of Se takes place through the stem portion of different trees where it constitutes 30–50% of total Se. Large variation in Se uptake by different tree species suggests that trees vary in their potential for phytoremediation of seleniferous soils. In one growing season, shisham aged 24 years, poplar (Populus deltoides)– Clone G 48 (10 years old) and eucalyptus – Clone 10 (10 years old) could remove 2385, 1845 and 1407 g Se per hectare respectively. Corresponding reductions in Se capital of the soil varied between 24 and 37, 19 and 29 and 14 and 32%, respectively, in the surface layer (0–15 cm) alone or 7–11, 6–9 and 4–7% for the whole soil profile (0–120 cm). Removal further increased to 4207 g Se per hectare under an agroforestry farming system of poplar–mentha/wheat with Se being reduced from 43 to 65% for the surface layer and from 13 to 20% for the whole profile.     

丁香[Syzygium aromaticum (L.) Merr.et Perry]挥发油中天然抗菌成分研究

研究结果表明，丁香[Syzygium aromaticum(L．)Merr．et Perry]挥发油及其衍生物均可抑制黑曲霉(Aspergillus niger)和扩展青霉(Penicillium expansun)的生长，丁香挥发油对黑曲霉的最小抑菌浓度为50％，对扩展青霉的最小抑菌浓度为25％；丁香挥发油衍生物对黑曲霉的最小抑菌浓度为25％，对扩展青霉的最小抑菌浓度为20％。用GCMS详细分析了丁香挥发油的化学成分，共鉴定了20个化合物，其中主要成分为丁香酚，含量占挥发油成分总量的68．0278％。     

三亚地区莲雾果园生态系统碳 储量及其分布特征

分别应用平均木法、样方收获法和分层取样法采样并测定三亚地区莲雾果园生态系统乔木层、草本及凋 落物层和土壤层的生物量及碳含量,并探讨了莲雾果园生态系统各组分的碳储量及其分布特征。结果表明,三亚地 区莲雾果园生态系统总碳储量为76.87 t/hm2,其中乔木层、草本及凋落物层和土壤层碳储量分别为11.63、1.21、64.03 t/hm2,分别占总碳储量的15.13%、1.57%、83.30%;乔木层各器官碳储量大小为树枝>树根>树叶>树干>果实;土壤层 随深度的增加碳储量逐渐降低。总体而言,三亚地区莲雾果园生态系统固碳潜力较大且系统碳储量主要位于土壤 层,乔木层碳储量以树枝和树根较多,草本及凋落物层碳储量较低。