| Dianthus plumarius is a perennial herb.In this article,one-year old Dianthus plumarius was used as materials to study systematically its physiological and ecological properties of photosynthesis,drought resistance and shade resistance in natural environment.The main results were as follows:1.The light compensation point of Dianthus plumarius was about 56.94μmol·m-2·s-1and the light saturation point was around 800μmol·m-2.s-1,so Dianthus plumarius is a heliophyte.2.The diurnal variation of net photosynthetic rate in spring(the last ten-day period of a month in March)and autumn(the beginning of October)had one peak curve,and the peak value was 10:30 and 13:00 respectively.However,the daily variation of net photosynthetic rate in summer(the last ten-day period of a month in June)showed the double-peak curve type,which had obvious midday photosynthetic depression,and the peak value was about 11:00 and 16:00.Its net photosynthetic rate in summer was highest and Its net photosynthetic rate in spring was higher than that in autumn.In different seasons,the main factors limiting the net photosynthetic rate of Dianthus plumarius were different.Correlation analysis and the path coefficient analysis between diurnal variation of net photosynthetic rate and its physio-ecological factors in Dianthus plumarius indicated that transpiration rate and temperature were the most important direct factors to influence the changes of net photosynthetic rate was in spring;Stomatal conductance,photosynthestically active radiation,intercellular CO2 concentration and ambient CO2 concentration in summer significantly correlated with net photosynthetic rate.The leading factors directly affecting net photosynthetic rate were relative humidity,intercellular CO2 concentration and temperature;In autumn,photosynthestically active radiation,intercellular CO2 concentration,temperature and transpiration rate extremely significantly correlated with net photosynthetic rate.Intercellular CO2 concentration and transpiration rate directly affected net photosynthetic rate.3.The diurnal variation of transpiration rate of Dianthus plumarius had one peak curve.Its transpiration rate in summer was clearly higher than that in spring and autumn,which was 20.25mmol·m-2·s-1.Transpiration rate was regulated by photosynthestically active radiation,intercellular CO2 concentration and temperature, and so on.4.The diurnal variation of water using efficiency of Dianthus plumarius had double-peak curve in summer and autumn.In spring,the curve of the diurnal variation of water using efficiency was considered as a single peak one.Its water using efficiency in spring and autumn was higher than that in summer.5.Leaf water-holding ability of Dianthus plurnarius was stronger.Under different water stress,relative water content,relative water deficit,cholorophyll content,relative electric conductivity and photosynthesis of Dianthus plumarius were measured,which concluded its drought resistance was stronger.6.Specific leaf area of Dianthus plumarius was small,which was124.50±8.24 (cm2·g-1).In shading treatments,its internode length increasd,and the length was increasing with shading treatment serious.In different shading treatments,relative water content,specific leaf weight,cholorophyll content and photosynthesis of Dianthus plumarius were measured,which concluded its shade resistance was weaker. |
