西江中上游人工次生林凋落物水文效应

在西江中上游肇庆市德庆三叉顶市级自然保护区,对人工次生林不同坡向的凋落物水文效应进行了研究,结果如下:(1)凋落物持水率与浸泡时间存在对数曲线关系,而凋落物吸水速率与浸泡时间呈指数函数关系;不同森林类型凋落物持水率和吸水速率随时间的动态变化规律基本相似;(2)不同坡向林分凋落物最大持水率的大小顺序为:东南坡(172.3...     

橘红心娃娃菜新品种九千娃娃菜1号的选育

九千娃娃菜1号是山东春秋大白菜育种研究中心以自交不亲和系夏08-219与自交不亲和系08-371配制而成的橘红心娃娃菜杂交种。该品种生育期50～55d,矮桩合抱舒心炮弹型,类胡萝卜素含量55.7mg·kg-1,单球质量0.32～2.1kg,做娃娃菜栽培667m2可种植0.8万～1.2万株,做大白菜栽培时4000株左右。抗病毒病、霜霉病、软腐病、干烧心等多种病害,适宜全国大部分地区晚春、夏秋季栽培。     

Nutrient composition and short-term release from <Emphasis Type="Italic">Croton macrostachyus</Emphasis> Del. and <Emphasis Type="Italic">Millettia ferruginea</Emphasis> (Hochst.) Baker leaves

A field study was conducted to investigate the nutrient content of green and abscised leaves of Croton macrostachyus Del. and Millettia ferruginea (Hochst.) Baker and their decomposition to return these nutrients to the soil in the short-term. Green and abscised leaves were collected from trees of comparable size in Wondo Genet, Ethiopia, and were incorporated into litterbags to decompose for a period of 12 weeks. Green leaves of C. macrostachyus had significantly higher nutrient concentrations than those of M. ferruginea. In both species, green leaves had significantly higher (P<0.05) C, N and P and significantly lower (P<0.05) lignin and polyphenol concentrations than abscised leaves. Fifty percent of the biomass applied was lost during the first 7 weeks in C. macrostachyus, which was about 3 times faster than that of M. ferruginea. The half-lives of N and P were 5–8 weeks and 4–6 weeks, respectively, in C. macrostachyus; the corresponding values for M. ferruginea were 6–8 and about 22 weeks, respectively. Only 15.7% and 26.8% of green and abscised leaves of C. macrostachyus, respectively, were recovered after the 12 weeks of decomposition. The corresponding values were about 3.5-fold and 2.5-fold higher for M. ferruginea. Generally, leaves with higher initial lignin, polyphenol, lignin:N and C:N ratios had lower decomposition and mineralization rates. In both species, removal of leaf biomass before abscission (e.g. by pruning) could enhance both the quantity and rate of nutrient return to the soil.     

不同时期四倍体刺槐叶片氨基酸营养及其生物量初步分析

测定了廊坊地区饲料型四倍体刺槐叶粉4个不同时期的粗蛋白质含量及18种氨基酸组分,用氨基酸分(AAS)和必需氨基酸指数(EAAI)对其氨基酸营养进行评价,并结合其生物量对最佳刈割时期进行了分析。结果表明,饲料型四倍体刺槐叶粉4个时期的粗蛋白1、8种氨基酸总量和12种必需氨基酸含量均较高,且呈现随时间的推移而逐渐下降的趋势;其必需氨基酸分(AAS)均较高,氨基酸组成较平衡;对牛、猪、鸡、鸭、鹅、草鱼、对虾和羊8种动物的必需氨基酸指数(EAAI)4个时期之间无差异,均大于0.86,可作为这些动物的优良植物饲料蛋白源;在7月中下旬其生物量和营养达到了最佳结合点,适宜采摘或刈割。     

Decomposition of leguminous crop residues in a ‘jhum’ cultivation system in Arunachal Pradesh,India

Decomposition of leaves, stems, and roots of two leguminous plants, french bean and pea, was studied in a ‘jhum’ cultivation (shifting agriculture) system in north‐eastern India in litter bag experiments. The dynamics of decomposition varied between the crop residues and species studied. All the three studied types of residues of french bean and the leaves and roots of pea showed polynomial decomposition model with three distinct phases: an initial slow decomposition phase (1), followed by a faster decomposition rate (2) and again by a slow decomposition phase (3). However, the stems of pea plants showed an exponential increase in the decomposition rate during field incubation. Initial N, lignin, and lignin : N ratio were determined in crop residues. In general, roots decomposed slowly as compared to the leaves and stems due to greater lignin content. Soil microbial activity as determined by CO₂ evolution was significantly correlated with the decomposition rates. Over all, the decay constants reveal that these fast decomposing leguminous crop residues can be properly managed for soil nutrient management in the low input shifting agricultural fields in the hills.     

西藏高原东部矮西沟流域土壤可蚀性研究

藏东矮西沟流域水土流失严重,土壤抗侵蚀能力差,是金沙江上游大量泥沙的主要来源之一。对研究区的土壤可蚀性的研究,无论是对草地和耕地的保护,还是对金沙江泥沙量的缓减,都具有重大的现实意义,是水土保持工作的基础。该文通过调查研究土壤抗侵蚀能力与土壤侵蚀特征,利用大量的实测资料,比较研究了3种K值模型估算值的数值特征,与调查结果的相关性以及估算值取值范围的可靠性,确定了西藏高原东部土壤K值的最优估算模型为通用流失方程K因子模型,不同土壤的K值大小顺序为灰褐土>高山草甸土>棕壤>暗棕壤,流域K值的平均值为0.005,在全国范围内较小。     

冻存茶鲜叶多酚氧化酶动力学特性研究

采用分光光度法对冻存处理的茶树鲜叶的多酚氧化酶(PPO)进行了活性测定,研究了底物浓度、pH值及温度对冻存茶鲜叶PPO活性的影响,建立了茶树鲜叶冻存-萎凋过程的反应动力学方程.结果表明,冻存茶鲜叶PPO酶活的最适条件为:pH值介于4.6～5.0之间,温度35～60℃.由Michelis-Menten方程1/v=1.16...     

桑叶黄酮含量测定及提取工艺研究进展

本文对从桑叶提取黄酮类化合物的各种方法,如醇提法、微波法、超临界CO2萃取和大孔树脂吸附法等进行系统的叙述;同时对桑叶中黄酮类化合物的分析方法,包括分光光度法与荧光光度法、高效液相色谱法（HPLC）、高效毛细管电泳法（HPCE）和微乳薄膜层析法进行概述和比较。     

微波辅助提取荷叶中槲皮素的工艺研究

槲皮素具有抗癌、抗氧化等多重功效,在食品、医药领域具有广泛的应用前景。为此,采用微波辅助工艺,乙醇回流浸提,研究了原料粒度、微波处理时间、微波功率和浸提溶剂配比对荷叶中槲皮素提取率的影响。结果为:原料粒度60目,微波功率450W处理2min,浸提溶剂为75%乙醇,料液比1∶16,70℃回流提取1.5h,荷叶中槲皮素的提取率最高为0.981%;相比于未进行微波处理样品,提取率提高了39.5%。研究结果为荷叶中槲皮素资源的开发利用,提供了新思路。     

基于球B样条函数的烟草叶片虚拟实现

植物三维形态的可视化模拟是数字植物研究的基础。该文综合应用球B样条曲线和插值B样条曲面实现了以脉序作为结构骨架的烟草叶片几何建模。首先利用三维数字化仪等数据获取装置获取烟草叶片脉序主要形态特征点的三维坐标和厚度,然后利用球B样条曲线对脉序进行三维建模,生成叶片的形态骨架,与由插值样条生成的叶片曲面合成,实现了烟草叶片的三维重建和真实感显示。结果表明,该方法得到的烟草叶片几何模型与传统方法相比具有较高的真实感,为植物叶片叶脉尺度的高真实感几何建模提供了新的手段。