Geographic Distribution Of Plants Leaf Minimum Stomata Conductance And Anaylasis

Stomata is a vital link between the carbon and water cycles in the ecosystem.Plant stomata not only regulate carbon assimilation and water loss,but they also reflect a plant’s ability to adapt to its surroundings.The stomata of plants were thought to be completely closed in the dark in early studies,and the stomatal conductance at night was thought to be a fixed value.Plant leaves’stomata,on the other hand,were not completely closed in the dark,according to a growing number of studies.In this situation,the minimum stomata conductance value used in earlier ecosystem models to calculate plant transpiration loss may have been overestimated.In dry to semi-arid locations,however,the ability of plants to deal with significant drought stress may be related to their lowest stomatal conductance.This study measured the leaf minimum stomatal conductance of 400 plants（belonging to 122 families and 297 genera）in 23 cities in China,according to the Chinese transect in the global change transect divided by IGBP（International Geoscience Society Programme）in 1995,and the altitude gradient of the sampling point,divide all these sampling points into three transects,to investigate the impact of different geographic locations,climate environments,growth types,leaf qualities,temperature,and air pollutants on minimum stomatal conductance,as well as the geographic distribution characteristics and influencing factors of minimum stomatal conductance.The results show that:1.The minimum stomatal conductance(g_min)is not a fixed value,but a variable with significant influenced by geographic location and other factors.More than 90%of g_min between 0-40 mmol/m²/s,and g_min has a significant positive correlation with latitude（p<0.05）.In the north-south transect,g_min has a significant negative correlation with multi-year average temperature and soil total organic carbon content（SOC）.The g_min showed a significant positive correlation with precipitation and SOC in the East-West Transect（p<0.05）.In the altitude transect,g_min decreased with the increase of altitude.The results showed that the geographical distribution of plants and their differences in hydrothermal conditions would lead to different sizes of the g_min of plant leaves.2.In different growth type classifications,there are various degrees of differences in g_min in each growth type group.Under three different growth types,the order of g_min size in each group is as follows:needle leaf<broad leaf<terrestrial herb<aquatic herb,evergreen<deciduous<perennial herb<annual herb,vine<shrub<arbor<herb.Leaf water potential,specific leaf area and leaf p H showed significant positive correlation with g_min and significant negative correlation with leaf carbon nitrogen ratio,but did not show significant correlation with leaf water content。3.In the short-term weather change,only the precipitation in the first 7 days before the test day shows a significant positive correlation with g_min,but does not show a significant correlation with a daily average temperature,daily average relative humidity and daily average sunshine hours.The impact of air pollution on g_min mainly comes from the 180 days mean value of long-term air pollution,and all pollution types show significant correlation with g_min,indicating that long-term air pollution will have a certain impact on leaf growth and development.In the experiment of g_min on the instantaneous temperature change,g_min showed a downward trend first and then an upward trend.