果蔬汁非热加工技术研究进展

阐述了果蔬汁非热加工新技术中超高压技术、脉冲电场技术和辐照杀菌技术的研究进展、作用效果和应用前景。     

农产品中真菌毒素γ辐照降解的研究进展

介绍了农产品中真菌毒素的危害性,综述了γ辐照对农产品中真菌毒素降解的研究进展。     

光合有效辐射预测模型的核函数组合优化

以林下参种植基地光合有效辐射( PAR)、散射辐射(PFDdif)和直射辐射(PFDdir)为研究对象,以支持向量机linear核函数(k1)、polynomial核函数(k2)、radial basis function核函数(k3)为基础,构建新核函数.使用K-fold交叉验证方法,利用粒子群算法(PSO)对惩罚参数c和g值优化.试验结果表明,利用grid search算法设定惩罚参数c为16和g值为1时,通过比较相关系数及符合拟合均衡原则下,选出以0.2k1+0.8k2核函数而构建的光合有效辐射预测模型效果最佳,对由PAR、PFDdir和PFDdif数据组成的预测集1和预测集2拟合程度分别为89.213 2％和81.789 6％.利用粒子群算法对惩罚参数c和g值优化后,预测模型对预测集1拟合程度达到92.156 0％,对预测集2拟合程度达到90.036 0％.可见,采用0.2k1+0.8k2核函数和PSO的支持向量机预测模型对PAR具备预测能力.     

湖南会同杉木人工林生态系统CO_2通量特征

利用开路式涡动相关系统与自动气象梯度观测系统2008年12个月的观测数据,研究会同13年生杉木人工林CO2通量特征。结果表明:13年生杉木人工林生态系统CO2通量日变化存在明显的季节差异,晴天平均碳汇持续时间表现为夏>春>秋>冬,平均日较差表现为夏>秋>春>冬,最大碳汇出现时间由早到晚依次为夏、秋、春和冬;1年中,月累积碳通量除1和2月为碳源外,其他各月均表现为碳汇,碳汇最大值出现在6月(-53.0gC·m-2);13年生杉木林的年碳汇总量为-255.3gC·m-2。白天CO2通量与光合有效辐射的关系可用Michaelis-Menten模型模拟(P<0.05),但模型参数随温度而异;夜间CO2通量与5cm土壤温度呈指数关系(P<0.05)。     

Evapotranspiraton estimation based on scaling up from leaf stomatal conductance to canopy conductance

Evapotranspiraton (ET) estimation based on scaling up from leaf stomatal conductance (g_s) to canopy conductance (g_c) is important in improving effective use and evaluation of agricultural water resources. Taking a summer maize field in north China as an example, after the response of g_s to main environmental factors was analyzed based on the measured value, the Jarvis model for g_s was established and calibrated. Then the weighted integration model (WI model) was established on the basis of weighted model (W model) after considering the difference of intercept diffuse radiation by shaded leaves in different canopy heights and nonlinear relationship between g_s and the photosynthetically active radiation (PAR) to improve g_c estimation for shaded leaves using integration equation. Meanwhile the estimation accuracy of W and WI models for g_c was compared, and then field ET was estimated using the Penman-Monteith equation. Results indicate that the variation of g_s was similar to that of PAR and the Jarvis model could better express the response of g_s to PAR, vapour pressure deficit and air temperature. Compared to the W model, WI model could effectively improve the estimation accuracy of g_c, with the relative error of 4.4%. Penman-Monteith equation overestimated λET by 9.4% using the estimated g_c by the W model, but underestimated λET by 2.3% using the estimated g_c by the WI model. Therefore, Penman-Monteith equation can estimate maize field ET using the estimated g_c by WI model in the region.     

UVB exposure does not accelerate rates of litter decomposition in a semi-arid riparian ecosystem

Aboveground litter decomposition is controlled mainly by substrate quality and climate factors across terrestrial ecosystems, but photodegradation from exposure to high-intensity ultraviolet-B (UVB) radiation may also be important in arid and semi-arid environments. We investigated the interactive effects of UVB exposure and litter quality on decomposition in a Tamarix-invaded riparian ecosystem during the establishment of an insect biological control agent in northern Nevada. Feeding by the northern tamarisk beetle (Diorhabda carinulata) on Tamarix spp. trees leads to altered leaf litter quality and increased exposure to solar UVB radiation from canopy opening. In addition, we examined the dynamics of litter decomposition of the invasive exotic Lepidium latifolium, because it is well-situated to invade beetle-infested Tamarix sites. Three leaf litter types (natural Tamarix, beetle-affected Tamarix, and L. latifolium) differing in substrate quality were decomposed in litterbags for one year in the field. Litterbags were subjected to one of three treatments: (1) Ambient UVB or (2) Reduced UVB (where UVB was manipulated by using clear plastic films that transmit or block UVB), and (3) No Cover (a control used to test for the effect of using the plastic films, i.e. a cover effect). Results showed a large cover effect on rates of decomposition and nutrient release, and our findings suggested that frequent cycles of freeze-thaw, and possibly rainfall intensity, influenced decomposition at this site. Contrary to our expectations, greater UVB exposure did not result in faster rates of decomposition. Greater UVB exposure resulted in decreased rates of decomposition and P release for the lower quality litter and no change in rates of decomposition and nutrient release for the two higher quality litter types, possibly due to a negative effect of UVB on soil microbes. Among litter types, rates of decomposition and net release of N and P followed this ranking: L. latifolium > beetle-affected Tamarix > natural Tamarix. Altered nutrient dynamics with beetle introduction as well as the rapid decomposition rates exhibited by L. latifolium are consistent with vulnerability to secondary invasion. In this desert ecosystem, decomposition and nutrient release were strongly affected by litter type and much less so by UVB exposure.     

两种剂量重离子辐照绵羊精子差异蛋白质组学研究

为检测和分析0.5和3.0Gy 2种剂量重离子辐照绵羊精子差异表达的蛋白质,用二维凝胶电泳分离精子蛋白,凝胶用硝酸银染色,PDQuest8.0检测分析差异表达蛋白斑点并经高效液相色谱串联离子阱质谱鉴定,结果显示:2种剂量凝胶图谱分析后得到8个共同差异蛋白斑点,鉴定为3种表达上调的蛋白质(谷氧还蛋白1、转录因子AP-2α...     

菊花辐射诱变种质创新研究进展

辐射诱变技术是创制菊花新种质的有效途径,可为观赏植物功能基因挖掘提供重要资源。综述了菊花辐射诱变育种的基本原理以及国内外菊花辐射诱变种质创新及变异机制研究进展,对不同射线辐射诱发菊花的花色、花期、抗性、叶型等表型变异进行了系统总结,着重介绍了高能重离子束在菊花种质创新及新品种选育中的应用,同时探讨了当前菊花辐射诱变育种存在的部分问题并给出了建议。     

特定电磁辐射(TDP)处理水稻种子及幼苗的研究

 由30多种元素,经一定温度场作用所辐射的特定电磁波,用于水稻温室育秧和种子处理,均能有效地增强萌发期和幼苗期多种酶的活性,促进新陈代谢,提高秧苗素质。移栽后速生快发,并可改善光合性能,协调穗部经济性状,使稻谷增产5%左右。     

臭椿光合生理生态特性日变化研究

为了解臭椿光合生理生态特性及生长的适宜生态条件,培育出优质高产的森林,采用LI-6400便携式光合测定系统对臭椿的光合生理特性日变化及其与气象因子关系进行了研究。结果表明:臭椿的净光合速率日变化呈"双峰"型曲线,有明显的"午休"现象,第一个峰出现在10:00左右,第二个峰出现在14:00左右,日最大净光合速率为18.9μmol/(m2·s)。气孔导度的日变化呈"双峰"型曲线,蒸腾速率的日变化呈"单峰"型曲线,蒸腾速率在很大程度上决定于气孔的活动状态。叶片水压亏缺的峰值与光合有效辐射和大气温度的峰值在同一时间出现,胞间CO2浓度因为气孔导度的降低而减少,臭椿的光合速率控制因子为气孔限制。各环境因子主要对蒸腾速率、水压亏缺和叶面温度的作用而影响的净光合速率,光合有效辐射对光合特征参数的变化影响最大,且对净光合速率起决定性作用,其相关系数为0.543。