The Study of Native Plants Water Consumption Characteristic in Gurbantunggut Desert

Abstract

The plants' sap flow can characterize water transpiration and consumption, reflect water transmission situation and then determine the vegetation ecological water requirement. This paper takes Haloxylon ammodendron and Tamarix as the research object, adopts thermal diffusion method[1], studies vegetation trunk fluid flow characteristics and the relationship between the meteorological factors. The results show that: (1) Haloxylon ammodendron and Tamarix's sap flux density are showed obvious diurnal variation rule, there is a "nap" phenomenon. Haloxylon ammodendron's liquid sap flux density of monthly mean performance is July > June >August, and Tamarix is July > August >June. (2) Haloxylon ammodendron's flow start time in cloudy is delayed about 1 ~ 1.5 h or so than in sunny day, and Tamarix is about 0.5 h delay. (3) Haloxylon ammodendron and Tamarix's fluid sap flux density in each month are significantly related to meteorological factors, through the regression analysis, Haloxylon ammodendron and Tamarix's trunk liquid sap flux density can make a regression model with meteorological factors.

Biliverdin chiral derivatives as chiroptical switches for pH and metal cation sensing

“…Certain organic molecules are unique in that the changes induced by physico-chemical agents and by the local environment may translate into changes of handedness for specially designed chiral systems: such changes can then be easily and reliably monitored by chiroptical methods, which date from the times of Biot & Fre ´snel to more recent methods from the last half-century or so. [13][14][15][16][17][18][19][20][21][22] As recent examples of such sensitive molecules, which of course are not at all exhaustive of the very many ones present in the literature, we recall those in which a change of helicity is occurring in molecules employed in material science, due to changes in the status of the environment. [23][24][25][26][27] Such changes depend on the structural characteristics of the designed molecular systems and are critically dependent on the presence of metal ions.…”