小苏干湖湿地典型泌盐植物海乳草叶性状和光合特性对淹水的响应

植物叶性状与光合生理特性对淹水的响应分析,有助于理解水淹生境中沼泽湿地植物叶片构建模型及其光合作用机理。按照小苏干湖湖水泛滥区静水持留时间长短变化设置：I （轻度淹水区,静水持留60-90 d）、Ⅱ （中度淹水区,静水持留90-150 d）、Ⅲ （重度淹水区,静水持留150-210 d）3个梯度,研究了小苏干湖湿地典型泌盐植物海乳草叶性状与光合生理特性对不同淹水生境的响应变化。结果表明：随着静水持留时间变长,土壤含水量逐渐增大,含盐量和光合有效辐射逐渐减小,湿地群落的盖度、密度呈增加趋势,地上生物量呈先减小后增加趋势;海乳草叶片的叶面积呈增加趋势,叶厚度、净光合速率和气孔导度呈减小趋势,叶干重和蒸腾速率变化不明显;不同生境条件下的海乳草净光合速率、蒸腾速率与叶面积、叶厚度之间均存在着显著差异（P<0.05）。随着静水持留时间的延长,海乳草选择增大叶面积,减小叶厚度的生长策略,适时调整叶片的净光合速率,实现植物叶片对吸收光能的有效利用,体现了植物在异质性生境中叶性状间的资源分配策略和光合产物积累模式。     

拟南芥抵抗丁香假单胞杆菌过程中AZI1基因功能研究

AZI1属于脂转移蛋白家族,它在拟南芥抵抗病原菌侵染过程中可能起着传递信号物质的作用。该实验以过表达和T-DNA插入突变体及野生型拟南芥植株为材料,通过RNA印迹、蛋白质免疫印迹和原位免疫组织化学方法,研究了拟南芥壬二酸诱导基因AZI1对丁香假单胞杆菌的抗性功能。结果表明:(1)AZI1基因可以被丁香假单胞杆菌、H2O2和乙烯利诱导,它可能参与水杨酸和乙烯介导的抗菌途径。(2)蛋白质免疫印迹实验结果显示,丁香假单胞杆菌侵染叶片的叶柄渗出液中存在AZI1蛋白及其同源物EARLI1,并能够与其他蛋白质形成复合体,说明AZI1有可能通过维管组织移动到个体的其他部位,与信号分子的转移有关。(3)AZI1及其同源物EARLI1主要在花序茎的木质化部位表达,过表达AZI1基因能够促进木质素的合成,提高拟南芥对丁香假单胞杆菌的抗性。     

福建省安溪县土地利用时空演变规律及其关键驱动因素

以福建省安溪县为研究边界,选取了1999—2019年该县及所属乡镇的耕地、林地、草地、园地、水域、建设用地和未利用地等7个土地利用类型作为物种变量,与其相关性较大的社会经济指标为环境变量,采用典范对应分析和空间自相关等方法进行分析,以明确安溪县和所属乡镇的土地利用时空演变特征及其关键驱动因素。研究结果表明:安溪县1999—2019年间土地利用类型变化总体上呈"三减四增"态势,并在全局空间分布格局上呈明显的聚焦状态。全县耕地、草地和水域面积分别减少36.82%、22.91%和8.18%,而林地、园地(主要是茶园)、建设用地和未利用地面积则分别增加了10.37%、56.39%、206.08%和90.14%。就林地面积而言,近10年来安溪县24个乡镇中有1/3的乡镇林地呈下降趋势。其中,祥华、大坪、虎邱、参内、福田和城厢6个乡镇林地面积减少明显。研究表明:在县域水平上,主要土地利用类型变化,除了受地理因素的制约外,主要受社会经济指标和宏观政策的驱动因素调控。排位最大的前3个因素分别是社会消费品零售总额、地区生产总值和茶叶产量。在镇域水平上,不同乡镇由于地理条件,特别是城镇化水平和经济发展状况...     

Experimental diabetes exacerbates autophagic flux impairment during myocardial I/R injury through calpain-mediated cleavage of Atg5/LAMP2

To explore the role of autophagic flux in the increased susceptibility of the experimental diabetic heart to ischaemia-reperfusion (I/R) injury, we established STZ-induced diabetic mice and performed I/R. In vitro, neonatal mouse cardiomyocytes were subjected to high glucose and hypoxia/reoxygenation challenge to mimic diabetic I/R injury. We found that experimental diabetes aggravated I/R-induced injury than compared with nondiabetic mice. Autophagic flux was impaired in I/R hearts, and the impairment was exacerbated in diabetic mice subjected to I/R with defective autophagosome formation and clearance. Calpains, calcium-dependent thiol proteases, were upregulated and highly activated after I/R of diabetes, while calpain inhibition attenuated cardiac function and cell death and partially restored autophagic flux. The expression levels of Atg5 and LAMP2, two crucial autophagy-related proteins, were significantly degraded in diabetic I/R hearts, alterations that were associated with calpain activation and could be reversed by calpain inhibition. Co-overexpression of Atg5 and LAMP2 reduced myocardial injury and normalized autophagic flux. In conclusion, experimental diabetes exacerbates autophagic flux impairment of cardiomyocytes under I/R stress, resulting in worse I/R-induced injury. Calpain activation and cleavage of Atg5 and LAMP2 at least partially account for the deterioration of autophagic flux impairment.     

拟南芥Pri-miR156a基因对烟草开花时间的影响

本研究利用转基因烟草分析了mi R156对SPL3基因的保守性调节作用。首先通过数据库搜索和RT-PCR方法克隆了普通烟草Ntab SPL3基因的编码序列,并进行了测序验证。同时从拟南芥Col-0生态型基因组DNA分离了At Pri-mi R156a基因序列,构建产生植物表达载体,采用农杆菌转化技术制备了转基因烟草植株。RT-PCR分析发现,过量表达Atmi R156a可以明显下调烟草Ntab SPL3基因。表型观察结果显示,At Pri-mi R156a转基因烟草个体矮小,开花时间明显延迟,叶片数量及生物量积累增多,说明组成性表达Atmi R156a能够延长普通烟草的营养生长时间,推迟开花转变过程。本研究为培育适合不同生长环境的烟草新品种提供了一条新的途径,对烟草改良具有重要意义。     

Analysis of the distribution of chemical elements in Adelie penguin bone using synchrotron radiation X-ray fluorescence

We performed synchrotron radiation X-ray fluorescence (SR-XRF) analysis of Adelie penguin bones, collected in the maritime Antarctic. This method enabled us to determine the microscopic concentration profiles of chemical elements in transverse bone sections. Results show that: (1) there are different concentration profiles for elements in the bones; (2) the inter-correlation of elements in the bones is complex; (3) some trace elements, including toxic ones like Rb, Sr, Fe, Mn, Cu, Co, Ni, Ti, Zr, Br, As, Hg, and Cr, are also detected somewhere in the cross section of the bones. It is suggested that further studies be conducted to establish an SR-XRF database for polar and non-polar animals. This will be greatly beneficial for characterizing penguins by the microscopic distribution of elements in bone and for the understanding of elements' roles in animal metabolism.