芍药采后贮藏生理研究

该文对芍药两个耐贮藏性不同的品种，在低温干燥贮藏过程中水分、乙烯、呼吸速率及呼吸途径等生理变化进行测定．结果表明，贮藏过程中花枝水分状况与切花寿命相关，没有发现呼吸、乙烯与切花寿命关联，呼吸途径变化与水分变化有一定联系     

Increased grain yield and biomass allocation in rice under cool night temperature

Abstract

The effects of different night temperatures on grain yield were examined in rice (Oryza sativa L. Akita-63) during the ripening period. Plants were grown under two different night temperatures (22 and 27°C) from anthesis to harvesting. The day temperature was maintained at 27°C in both treatments. Although the final biomass at harvest did not differ between the treatments, the dry weight of the panicles was significantly greater in the cool night temperature treatment. This increase in panicle weight was associated with increases in the 1000-kernel weight and the ratio of filled spikelets. Although panicle respiration in the high night temperature treatment decreased to almost zero just after the cessation of grain filling, the net CO₂ fixation rate per day in the whole plant in this treatment tended to be higher, and this was associated with a higher level of starch accumulation. After grain filling, the starch content decreased and the final dry weight of other plant parts, including dead organs and new tillers, was greater in the high night temperature treatment. Thus, the noted decline in yield at the high night temperature led to changes in carbon allocation to new sinks for vegetative reproduction at the whole plant level. From these results, we considered the possibility that a cool night temperature tends to favor carbon allocation to panicles, resulting in higher yield.     

栓皮栎对CO2增长的生理生态响应

通过对 5 0年生栓皮栎天然次生林叶片的活体测定 ,研究了CO2 浓度增长对栓皮栎林光合生理生态特性的影响 .结果如下 :CO2 浓度为 80 0 μmolCO2 ·mol- 1 时栓皮栎叶片的净光合速率比在正常大气CO2 条件下提高 42 .5 3 % ,同时光补偿点降低 ,光饱和点提高 ,光量子效率提高 ;CO2 浓度为 80 0 μmolCO2 ·mol- 1 时 ,栓皮栎净光合速率的日变化为单峰曲线 ,而CO2 浓度为40 0 μmolCO2 mol- 1 时 ,净光合作用的日变化为双峰曲线 ;CO2 浓度倍增 ,栓皮栎叶片的气孔导度 ,蒸腾速率和暗呼吸速率降低 ,水分利用效率显著提高 .栓皮栎叶片对CO2 增长的反应 ,对其生长是有利的 ,对全球CO2 浓度增长起到反馈调节作用 .     

The contribution of root respiration of<Emphasis Type="Italic">Pinus koraiensis</Emphasis> seedlings to total soil respiration under elevated CO<Subscript>2</Subscript> concentrations

The impacts of elevated atmospheric CO₂ concentrations (500 μmol·mol⁻¹ and 700 μmol·mol⁻¹) on total soil respiration and the contribution of root respiration ofPinus koraiensis seedlings were investigated from May to October in 2003 at the Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, Jilin Province, China. After four growing seasons in top-open chambers exposed to elevated CO₂, the total soil respiration and roots respiration ofPinus koraiensis seedlings were measured by a Li-6400-09 soil CO₂ flux chamber. Three PVC cylinders in each chamber were inserted about 30 cm into the soil instantaneously to terminate the supply of current photosynthates from the tree canopy to roots for separating the root respiration from total soil respiration. Soil respirations both inside and outside of the cylinders were measured on June 16, August 20 and October 8, respectively. The results indicated that: there was a marked diurnal change in air temperature and soil temperature at depth of 5 cm on June 16, the maximum of soil temperature at depth of 5 cm lagged behind that of air temperature, no differences in temperature between treatments were found (P>0.05). The total soil respiration and soil respiration with roots severed showed strong diurnal and seasonal patterns. There was marked difference in total soil respiration and soil respiration with roots severed between treatments (P<0.01); Mean total soil respiration and contribution of root under different treatments were 3.26, 4.78 and 1.47 μmol·m⁻²·s⁻¹, 11.5%, 43.1% and 27.9% on June 16, August 20 and October 8, respectively. Foundation item: This study was supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX1-SW-01) and the National Natural Science Foundation of China (30070158). Biography: LIU Ying (1976-), female, Ph. D. Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China. Responsible editor: Song Funan     

环境因子对胶南沿海防护林土壤呼吸的影响

对胶南沿海防护林灌草带和混交林的土壤呼吸速率及其环境因子进行了研究，结果表明：两个类型林地的土壤呼吸速率日变化均呈现出单峰式的变化规律；地表温度是影响土壤呼吸速率的最关键因子，与两个类型的土壤呼吸速率都呈极显著正相关关系，相关系数分别是0．958、0．980；气温也是影响土壤呼吸速率的重要因素，与灌草带土壤呼吸速率呈显著正相关，相关系数是0．857；大气温度、土壤湿度和风速对土壤呼吸速率都有一定影响，但不显著，其中风速对土壤呼吸的影响有待于进一步研究。通过逐步回归方法，得出海防林土壤呼吸速率的主要环境因子与土壤呼吸速率之间的回归模型。     

中亚热带天然林改造成人工林后土壤呼吸的变化特征

【目的】研究中亚热带常绿阔叶林(天然林)改造成人工林后土壤碳排放量的变化及主要影响因子,为评估森林类型转换对土壤碳排放的影响提供科学依据。【方法】在福建农林大学西芹教学林场的常绿阔叶林及由其改造而来的38年生闽楠人工林与35年生杉木人工林中分别设置4块20 m×20 m样地,利用Li-8100土壤碳通量观测系统于2014年9月—2016年9月进行定点观测,并同期观测土壤温度、含水量、有机碳含量(SOC)、微生物生物量碳含量(MBC)、可溶性有机碳含量(DOC)、0～20 cm土层细根生物量和年凋落物量及凋落物碳氮比(C/N)。【结果】常绿阔叶林改造成闽楠(38年后)和杉木人工林(35年后),年均土壤碳排放通量由16. 22显著降为12. 71和4. 83 tC·hm^-2a^-1,分别减少21. 60%和70. 20%;各林分类型的土壤呼吸温度敏感性Q¹⁰值表现为常绿阔叶林(1. 97)<闽楠人工林(2. 03)<杉木人工林(2. 91),转换为杉木人工林后,Q¹⁰值显著升高(P<0. 05);土壤温度能分别解释常绿阔叶林、闽楠人工林与杉木人工林土壤呼吸速率变化的89. 70%、88. 50%和87. 90%,土壤呼吸速率和土壤含水量相关不显著(P>0. 05);土壤呼吸速率和SOC、MBC、DOC、年凋落物量及0～20 cm土层细根生物量均极显著正相关(P<0. 01);土壤呼吸温度敏感性指数Q¹⁰值和凋落物C/N极显著正相关(P<0. 01),而与年均土壤呼吸速率及MBC极显著负相关(P<0. 01);进一步分析发现土壤MBC和SOC含量是影响土壤呼吸速率的2个最重要因子,而凋落物C/N在影响土壤呼吸温度敏感性中的贡献最大。【结论】中亚热带地区常绿阔叶林改造成闽楠(38年)或杉木(35年)人工林后,土壤碳排放通量显著降低。林分类型转换后树种组成和林分结构发生改变,凋落物数量、质量及细根生物量显著降低,土壤SOC和MBC含量显著下降可共同导致土壤呼吸通量的下降。土壤温度是3种林分类型土壤呼吸季节变化的主导因素,而土壤总有机碳库和土壤微生物量碳库的差异是不同林分之间土壤呼吸差异的主导因素,凋落物C/N对土壤呼吸的Q¹⁰影响最大。为提高模型预测森林类型转换影响土壤碳排放的精度,应综合考虑土壤有机碳库、易变性有机碳库及底物质量的变化。     

土壤呼吸影响因素研究进展

随着二氧化碳浓度的升高,全球变暖问题受到越来越多的关注。土壤是陆地生态系统最大的碳源,也是最大的碳汇。研究土壤呼吸作用对预测大气二氧化碳浓度变化,控制气候变暖,具有重要的意义。文章对土壤呼吸作用及其影响因素作了简要分析,为以后土壤呼吸方面的研究提供参考。     

毛竹林土壤呼吸研究进展

介绍和分析了毛竹(Phyllostachys heterocycla cv.pubescens)林土壤呼吸的研究方法、影响因子、时空变化、干扰响应、组分区分、模型构建等方面取得的研究成果,提出了今后毛竹林土壤呼吸研究应该加强:①土壤温度对毛竹林土壤呼吸影响机制研究;②对毛竹林土壤呼吸的时空变化进行长期的定位研究;③继续优化数学模型;④采用更多样化的方法来研究土壤呼吸各组分.     

择伐对小兴安岭地区针阔混交林土壤呼吸温度敏感性的影响

利用LI8100土壤二氧化碳排放通量全自动测量系统,测定小兴安岭地区针阔混交林不同强度择伐后4年的林地土壤呼吸速率和土壤温度。运用Q10模型分析择伐后林地土壤呼吸速率对土壤温度的敏感性。结果表明:择伐后林地Q10值高于未采伐林地,较高强度(60%,71%)的择伐使土壤呼吸速率对土壤温度具有高的敏感性。这一现象是3个土壤各组分呼吸对土壤温度响应综合作用的结果。枯枝落叶层呼吸速率对土壤温度的敏感性较差,根呼吸速率和矿质土壤层呼吸速率对土壤温度的敏感性较高。     

野生欧李生长期各组织器官中不同形态钙的分配率变化

以野生欧李为试材,逐级提取不同形态的钙,研究欧李生长发育阶段(萌动期-开花期-果实发育期)主要结果基生枝各组织器官(木质部、韧皮部、花和果实、新梢)中不同形态钙(水溶钙、果胶钙、磷酸钙、草酸钙、剩余钙)的分配率变化及其与总钙分配的相关关系。结果表明:不同组织器官中钙吸收和分配与钙形态转化和分配密切相关,随欧李生长期发育进程,木质部和韧皮部中不同形态钙分配呈明显下降趋势,新梢中不同形态钙分配呈明显增长趋势,花器官中水溶钙、果胶钙和磷酸钙形态在盛花期均有一分配高峰,果实中果胶钙和水溶钙形态分配分别在果实发育初期和后期有一分配高峰;花和果实总钙分配率变化与输导组织器官木质部和韧皮部中各种形态钙的分配呈显著或极显著正相关关系,新梢总钙分配率变化与输导组织器官木质部和韧皮部中各种形态钙的分配呈显著或极显著负相关关系。欧李生长期结果基生枝各组织器官中存在钙形态转化与再分配,水溶钙和果胶钙形态是欧李果实钙素吸收积累的主要钙形态。