美国凌霄光合生理参数对水分与光照的响应

该文利用CIRAS -2型便携式光合作用仪测定了不同土壤湿度下3年生美国凌霄叶片净光合速率（Pn）、蒸腾速率（Tr）、水分利用效率（WUE）及光能利用效率（LUE）等生理参数的光响应过程,阐明了其光合生理参数对土壤湿度和光照强度的响应规律,探讨了美国凌霄正常生长发育所需的土壤水分和光照条件。结果表明:美国凌霄的Pn、Tr、LUE及WUE对土壤湿度和光照强度的变化具有明显的阈值响应。①采用非直角双曲线模型进行模拟光响应过程较好,光响应曲线曲角接近于1。随着质量含水量Wm (5.5％～19.4％)、相对含水量Wr（20.1％～71.1％）的递增,光补偿点降低,光饱和点、最大净光合速率及表观量子效率均升高。在Wm为19.4％时,光补偿点最低(21.61 μmol/（m2·s）),光饱和点最高(1 400 μmol/(m2·s))。②维持美国凌霄正常生长、同时具有较高Pn、LUE及WUE的土壤湿度范围,在Wm为13.5%～19.4%（Wr为49.5%～71.1%）之间,最佳土壤湿度的Wm为19.4%（Wr为71.1%）,正常生长的最低土壤湿度Wm为7.7%（Wr为28.2%）。③美国凌霄对光照环境的适应性较强,在光合有效辐射强度为800～1 600 μmol/(m2·s)范围内,Pn和WUE都具有较高水平,饱和光强大约在800～1 400 μmol/(m2·s)之间,LUE在100～300 μmol/(m2·s)光强范围内达到峰值。      

Reactive oxygen species activity in the interaction of rice with Erwinia chrysanthemi pv. zeae

Activities of reactive oxygen species (ROS) were investigated in the interaction between rice and Erwinia chrysanthemi pv. zeae. Results showed that O₂·⁻, H₂O₂ and malondialdehyde (MDA) in resistant variety (128) had higher increases in activity compared to those in the susceptible variety (Texian 13) 24 hours after bacteria inoculation. The activities of superoxide dismutase (SOD) increased in 128 and Texian 13 twenty-four hours after inoculation and then decreased, but the SOD activity in 128 was found to be usually lower than that in Texian 13. The CAT activity in Texian 13 had two peaks at 24 h and 96 h after inoculation, while little change was seen in 128. In conclusion, ROS and its related enzymes could be correlated to rice resistance against E. chrysanthemi pv. zeae. __________ Translated from Journal of Huazhong Agricultural University, 2007, 26(4): 451–455 [译自: 华中农业大学学报]     

植物体细胞无性系变异的研究进展

 植物体细胞无性系变异是组织培养过程中的普遍现象。本文综述了有关植物体细胞无性系变异的影响因素、类型、机理等方面的研究成果。     

Genetic Diversity for Seed Mineral Composition in the Wild Legume <Emphasis Type="Italic">Teramnus labialis</Emphasis>

Teramnus labialis (L.) Spreng. is a wild, tropical legume whose seeds are collected and used as a food source by tribal populations. In order to assess the potential of this legume to provide dietary minerals for humans, fourteen diverse accessions were grown under controlled, nutrient-replete conditions and seeds were harvested for mineral analysis. The germplasm originated from Indonesia, Africa, the Caribbean, and South America. Seed concentrations of phosphorus (P), potassium (K), sodium (Na), iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn) were found to fall within the range of published values for several cultivated grain legumes, while calcium (Ca) and magnesium (Mg) were higher in T. labialis seeds. Mineral concentrations across the diverse accessions showed ranges of 1.3- to 2.3-fold for the macronutrient minerals (Ca, Mg, P, K) and 1.8- to 15.9-fold for the micronutrient minerals (Fe, Cu, Mn, Zn, and Na). The existing genetic diversity in this wild legume, especially for the essential minerals Ca and Mg, could be exploited to develop T. labialis as a new cultivated legume for tropical regions of the world.     

天然矿物对茶园土壤中铅的固定作用

茶园土壤中铅的生物有效性直接影响茶叶中铅的积累。为了解外加天然矿物对土壤中铅的固定作用,本文比较研究了4种矿物(高岭石、膨润土、沸石和磷灰石)在不同加入量和不同磨细程度条件下对土壤交换态铅和水溶性铅的影响。结果表明,加入矿物改良剂对土壤有效态铅(交换态铅和水溶性铅)有明显的降低作用,其效果与矿物类型、矿物加入量及加入矿物的磨细程度等有关。矿物对土壤有效铅的降低作用是:磷灰石>沸石>膨润土>高岭石。过100目处理矿物对土壤中铅的固定效果高于过18目处理的矿物。加入矿物对土壤水溶性铅的降低作用明显高于对交换态Pb的作用。结果认为,用天然矿物来改良铅污染茶园土壤、降低土壤有效铅是可行的。当土壤铅污染水平较低时,加入矿物量为20g/kg已能达到改良效果。     

锁阳综合研究概况

系统地总结了高原药用植物锁阳的生物学特性、化学成分及其药理药效与产品开发等方面的研究进展。针对我国中药材产业的发展趋势分析了锁阳开发研究中存在的问题、对策及发展前景。     

富钾植物籽粒苋(Amaranthus spp.)对土壤矿物钾的吸收利用研究

运用土培、石英砂培、有机酸释钾实验及矿物X衍射分析研究了不同基因型籽粒苋(Amaranthusspp.)对土壤矿物钾的吸收利用及其机制。结果表明,籽粒苋能有效地利用土壤和云母(黑云母和金云母)中的钾;籽粒苋品种R104、CX4对钾的吸收量高于一般型品种(CX77);籽粒苋根系能引起云母矿物向蛭石转化;籽粒苋根系分泌物中的草酸比一般有机酸具有更高的释放矿物中钾素的能力。     

活性氧及膜脂过氧化与棉花对枯萎病抗性的关系

 萎病菌侵染后,抗病品种棉苗及经氟乐灵诱发处理产生对枯萎病诱导抗性的棉苗茎与根组织中,膜脂过氧化产物丙二醛(MDA)含量上升,膜系统中不饱和脂肪酸含量下降,表明有膜脂过氧化的发生,超氧阴离子(O₂^·)的产生速率、H₂O₂的积累水平及脂氧合酶(LOX)活性也明显增加,但超氧化物歧化酶(SOD)及过氧化氢酶(CAT)活性无显著差异。与此相反,感病品种棉苗受侵后MDA含量、O₂^·产生速率、H₂O₂的积累及LOX酶活性增加幅度较小,SOD及CAT酶活性则明显上升,膜系统中不饱和脂肪酸含量仅有小幅度下降。氟乐灵播前土壤处理可诱发棉苗对枯萎病的诱导抗性,同时也增加了LOX酶活性及活性氧(O₂^·、H₂O₂)的积累。这些结果说明,枯萎病菌侵染后棉苗体内活性氧的积累、LOX酶活性的上升以及由此引起的膜脂过氧化,可能在棉苗对枯萎病的抗性中起作用。     

Sorption of L-methionine-sulphoximine on humic acids and clay minerals

 The sorption of L-methionine-sulphoximine (MSX) on soil-extracted humic fractions (MW>20,000 Da), and mined clays (kaolinite and montmorillonite) was studied by a reversed-phase high-performance liquid chromatography method. The molecule, acting as an inhibitor of glutamine synthetase activity, was recently used in soil incubation assays for the determination of gross rates of N mineralization. Equilibrium data of MSX adsorbed on humic fractions and clay minerals were described by both the Freundlich and Langmuir sorption isotherms. It was observed that humic fractions were more effective than mined clay minerals in removing MSX from water. Most isotherms were of Langmuir type, indicating a higher affinity of MSX for sorbing sites which become increasingly saturated at higher equilibrium concentrations. Analysis of Langmuir empirical constants revealed that different adsorbing mechanisms took place. Results showed that when MSX is applied in soil incubation assays, sorption of MSX on soil colloids considerably reduces the availability of the inhibitor to target microorganisms, and renders the method unsuitable for the determination of the gross rate of N mineralization, especially when high levels of both organic matter and clay minerals are present in the soil. Received: 19 April 1999     

Lithological factors affecting magnetic susceptibility of subtropical soils, Zhejiang Province, China

Magnetic susceptibility (χ) was measured on subtropical soils formed on a range of parent materials in Zhejiang Province, China, to demonstrate the influence of parent material lithologies on the amount and vertical distribution of χ in the soils. We found that the χ values of soils vary by up to two orders of magnitude with their parent material lithologies. Soils formed on igneous rocks with high χ values showed high absolute χ and distinctly decreased χ compared with χ values of parent materials. The χ values of soils formed on basalt, andesite and granodiorite were >250×10⁻⁸ m³ kg⁻¹. The χ values of soils formed on granite, and other neutral and acid igneous rocks ranged from 50×10⁻⁸ to 120×10⁻⁸ m³ kg⁻¹. In most of the soils formed on sedimentary rocks, χ enhancement in upper horizons of soils was found compared with parent material χ. This enhancement was believed to be pedogenic formation of superparamagnetic (SP)–stable single domain (SSD) magnetic grains, which are characterized by high values of frequency dependent susceptibility (χ_fd) and anhysteretic remanent magnetization (ARM). Soils formed on sedimentary rocks with a very low initial χ and iron content showed a low χ value throughout the profile. It was found that there is a highly significant relationship between the χ values of soils and their dithionite–citrate–bicarbonate solution (DCB) soluble iron contents (Fe_d). The χ values of soils in chronosequences formed on alluvium and two marine deposits increased as soils became older. It is suggested that the χ values can be used as a tool for determining the relative age in chronosequence studies.