| Temperature and precipitation are the key environmental factors affecting plant growth.Since the industrial revolution,the increasing human activities have caused global warming,which is accompanied by the change of global and regional precipitation pattern.Desert ecosystem is one of the most vulnerable terrestrial ecosystems,and its response to temperature and precipitation changes is ahead of time.The change of functional traits is the specific embodiment of adaptation strategies and internal functional trade-off strategies in response to environmental changes in the process of plant growth.The response of functional traits of desert perennial shrub Lycium ruthenicum Murr.to climate change is not clear.In this study,Lycium ruthenicum was taken as the research object,and the open top growth chamber was used to simulate climate warming,while artificial irrigation was applied to simulate humidification.We then observed and measured the phenology of leaf development,flowering and fruiting at individual and population levels,plant growth,cloning and sexual reproduction,as well as leaf morphological structure and photosynthetic characteristics of the plants,to analyze the adaptive responses of phenology,growth,propagation and leaf functional characteristics of Lycium ruthenicum to warming and humidification,in order to provide theoretical basis for the ecological and economic construction of desert areas.The main results are as follows:?1?After warming treatment,the beginning of leaf development of Lycium ruthenicum was significantly earlier than that of the control?P<0.05?,the duration of leaf development was significantly shortened by 10.9 days?P<0.05?,the beginning of leaf loss was significantly delayed by 3.2 days?P<0.05?,the duration of leaf loss was significantly prolonged by 3.3 days?P<0.05?,and the growth season was significantly prolonged by 10.3days?P<0.05?.The growth season of Lycium ruthenicum was significantly prolonged by 4.5days and 10.4 days respectively?P<0.05?.The effect of humidifying treatment is weaker than that of warming treatment,and the effect of warming and humidifying is similar to that of warming.?2?The flowering time of individuals and populations of Lycium ruthenicum was 7.2days and 8.3 days earlier than that of the control?P<0.05?,and the flowering duration was16.3 days and 12.3 days shorter than that of the control?P<0.05?.The effect of humidification on flowering phenology was weaker than that of warming,and the flowering duration of individuals and populations was not significantly different from that of the control,which were 15.9 days and 14.0 days longer than that of warming?P<0.05?.The effect of temperature and humidity increasing treatment on flowering duration was stronger than that of temperature increasing treatment,which was 20.2 days and 15.3 days shorter than that of the control,and 3.9 days and 3 days shorter than that of temperature increasing treatment,respectively.The flowering amplitude curve of Lycium ruthenicum under the treatment of increasing temperature and humidity showed double peak curve,the flowering mode was"centralized flowering",the flowering synchronization index was 0.83,and the average flowering amplitude was 75.5 and 83.6 respectively.The flowering amplitude curves of both the moistening and the control were multi peak,the flowering pattern was"multi peak",the flowering synchronicity index was 0.90,and the average flowering amplitude was 43.3 and41.6,respectively.The duration of single flower opening of Lycium ruthenicum was significantly different among the treatments?P<0.05?,the warming time?23.7 h?<warming time?33.0 h?<humidifying time?46.6 h?<control time?54.1 h?.?3?The fruit growth period of Lycium ruthenicum was shortened by 6.8 days?P<0.05?.Compared with the control,the beginning of fruit phenology was 9.4 days earlier,2.8 days later,and the growth period of fruit was 4.1 days longer?P<0.05?,10.9 days longer.The fruit growth period was significantly shortened by 16.4 days?P<0.05?,9.6 days and 20.5 days respectively.?4?From June to July,the clonal reproduction time of Lycium ruthenicum was concentrated.The clonal number?90,61?and clonal size?375,309?of humidification and control plots were significantly larger than those of warming plus humidification?P<0.05?,but there was no significant difference between humidification and the control,or warming and humidification?P>0.05?.The average number of flowers?1582.8?and fruits?673.7?per plant,total fruit weight per plant?0.39g?and seed number per fruit?25.4?were significantly higher than those in the control?474.2,231.7,0.28g and 5.3,respectively?,and the effect of warming treatment on sexual reproduction was lower than that of warming plus humidifying treatment,but higher than that of humidifying treatment.The results showed that there was a significant trade-off between clonal growth and sexual reproduction.?5?The leaf thickness?0.9074 mm,0.8631 mm?of Lycium ruthenicum in warming and warmng plus humidifying was significantly lower than that of the control?1.1086 mm?and the humidification?1.065 mm?,but the specific leaf area?48.71 cm.g,45.38 cm.g?,dry matter content?0.1045 g·g,0.1294 g·g?,leaf tissue density?0.2302 g·cm,0.2542 g·cm?,net photosynthetic rate(18.58?mol m-2.s,19.53,transpiration rate?5.39 mmol m.s,5.66 mmol?,stomatal conductance?0.3977 mmol,0.3893 mmol?,stomatal density?188.19 mm,126.24mm?,stomatal length?19.027?m,20.4?m?were significantly higher than those of the control and humidification treatments?P<0.05?.The results showed that Lycium ruthenicum could change the leaf function traits according to the habitat condition,maintain and guarantee the balance between its plant growth and nutrient cycle,and adapt to the environment change better.The above results show that the growth season of Lycium ruthenicum will be prolonged,the leaves will have higher photosynthetic capacity and accumulate more assimilates,the resource input for sexual reproduction will increase,and the population size and distribution area may further expand under future climate change scenario. |
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