Effect of imitated global warming on Delta C-13 values in seven plant species growing in Tibet alpine meadows

Open-top chambers were used to estimate the possible effects of global warming on delta C-13 of seven plant species grown in alpine meadow ecosystem. The delta C-13 values of plant species were lower after long-term growth in open-top chambers. In the course of experiment, temperature significantly increased inside the chambers by 4 degrees C. Plant species grown at a lower elevation above sea level had higher delta C-13 values as compared to those grown at a higher elevation. This was in accordance with the effect of open-top chamber on delta C-13 values in plants. Greater availability of CO2 and lower water vapor as indicated by an increase in discrimination against (CO2)-C-13, probably result in more negative delta C-13 values of plants because higher stomatal conductance increases availability of CO2 and causes greater discrimination against (CO2)-C-13. The plant species studied could be the indicator species for testing global warming by the change in carbon isotope ratios at the two growth temperatures.

Effects of La3+ on the active oxygen-scavenging enzyme activities in cucumber seedling leaves

The effects of La3+ on the antioxidant enzyme activities and the relative indices of cellular damage in cucumber seedling leaves were studied. When cucumber seedlings were treated with low concentrations of LaCl3 (0.002 and 0.02 mM), peroxidase (PO) activity increased, and catalase (CAT) activity was similar to that of control leaves at 0.002 mM La3+ and increased at 0.02 mM La3+, whereas superoxide dismutase (SOD) activity did not change significantly. The increase in the contents of chlorophyll (including chlorophylls a and b), carotenoids in parallel with the decrease in the level of malondialdehyde (MDA) suggested that low concentration of La3+ promoted plant growth. However, except the increase in SOD activity at 2 mM La3+, CAT and PO activities and the contents of pigments decreased at high concentrations of La3+ (0.2 and 2 mM), leading to the increase of MDA content and the inhibition of plant growth. It is suggested that lanthanum ion is involved in the regulation of active oxygen-scavenging enzyme activities during plant growth.

一种光纤陀螺仪的开发

介绍了应用前苏联Fizoptika公司生产的 94 1 3AM光纤陀螺传感器 ,利用单片机最小系统开发了角速度测量和旋转角度测量仪 ,可测量旋转物体的角度和角速度 .给出了光纤陀螺仪的硬件组成、软件设计思想及标定方法

K/E之交环境地球化学元素的演化与全球变化及恐龙绝灭的关系-以黑龙江中下游地区和俄罗斯远东地区为例

In this paper, We analyzed the geological and geographical settings of dinosaurs extinction at the end of Cretaceous, especially the effect of the change of the elements contents on dinosaurs extinction. We studied basis on the two typical sections-Cretaceous-Paleocene boundary (Baishantou section (in Jiayin, Heilongjiang province of China) and Arkhara-Boguchan Coal Mine section (in Far East of Russian)) and Longgushan section (in Jiayin, Heilongjiang province of China) mainly. This work provided some evidences for forecasting the effects of global environmental change on bio-circle. The followings are the primary gains: According to the paleo-climate indexes (CaO/MgO,Sr/Ba) and the results of Factor Analysis, we found that there were similar climate in Baishantou section and Arkhara-Boguchan Coal Mine section near the K/E boundary, and both of them took on the trend of temperature declining and precipitation heightening after transitory high-temperature and drought. There are similar change and evlution rule of the elements contents near the boundary in the both sections (Baishantou section and Arkhara-Boguchan Coal Mine section). Both iron group elements and chalcophile elements appeared obvious abnormity. There are not visible correlation between the change of elements contents and climate indexes. This shows that the elements abnormity maybe came from the factors excluding climate or the factors were too many to conceal the influence of climate. --The result of cluster analysis showed that the boundary between BST3-8 and BST3-9 may be the K/E boundary of Baishantou section, and the top of twofold coal were the K/E boundary of Arkhara-Boguchan Coal Mine section which was consistent with accepted conclusion formerly. By contrast of elements contents in dinosaur bones and general organism, in surrounding rock and general sand stone, the regulation of the change of elements contents in dinosaur bones and surrounding rock, we confirmed that dinosaur extinction in Jiayin were relative with the high abnormities of Sr, Ba, Pb, Cr and the low abnormity of Zn, at least, it was them which speeded up dinosaurs extinction. After a series of analysis, we concluded that dinosaurs extinction of this areas tied up with the relative high background values of geo-chemical elements , paleo-climate and disaster incidents. First of all, high background values provided the necessary condition for the accumulation of the elements. Secondly, the drought climate adverse to the survival of dinosaurs, and led them to extinct gradually. finally, disaster incidents, the eruption of volcano or the collision of aerolites, made them exit this planet.