| Acer truncatum Bunge is an important garden tree species in China.It is also a kind of woody oil species which is mainly developed by the state.Its oil content is 42.6%-48%,and it is rich in nerve acid and has great development value.It is mainly distributed in Beijing,Hebei,Shandong,Henan west,Shanxi and northeast and other places.Because it has excellent resistance to dry heat,we can understand the physiological and biochemical indexes of the two non-biological environmental factors stress and reflect the photosynthetic and chlorophyll fluorescence parameters of Ganoderma lucidum under the condition of dry and heat,and take effective measures Which can provide important reference for the injury of other plants,and provide some guiding significance for the introduction and scale planting of Yuanbaofeng to the harsh areas of the climate and dry heat,and lay the theoretical foundation for the further application of the ingot industry.In this experiment,Acer truncatum Bunge seedlings were used as experimental materials,and the dry heat stress of Acer truncatum Bunge was studied.The dry and heat stress experiments were carried out.The soil moisture content was controlled by artificial temperature in the artificial climate chamber.Effects of Different Dry Heat Levels on Osmotic Adjustment Substances,Photosynthetic Fluorescence Parameters,Chlorophyll Content and Antioxidant Enzymes of.(D0),moderate drought 50%(D1)and severe drought 30%(D2);25℃/20℃(T0)、30℃/25℃(T1)、35℃/25℃(T2)and 40℃/25℃(T3).research shows:1.With increasing the degree of heat stress,Acer truncatum osmolyte content increased and then decreased,soluble protein in 35 degrees of severe drought conditions reached the maximum,and then decreased significantly,the conductivity of 40 degrees in the severe drought conditions reached the highest,that of Acer truncatum at 35 DEG C accumulation of soluble protein content in order to regulate the permeability of the cell membrane,with the dry degree increased,the permeability of cell membrane was destroyed,resulting in increased conductivity.2.Under different dry and heat stress conditions,the activity of leaf enzyme was different,and the activity of superoxide dismutase(SOD)reached the maximum at 25℃,and catalase(CAT)and peroxidase(POD)activity reached the maximum under 40℃severe drought condition,which indicated that ingot was used to resist the dry heat caused by the increase of SOD activity in the dry and dry environment.With the increase of dry heat stress,CAT and POD replaces SOD enzyme against external stress.Under the same temperature and drought conditions,the changes of antioxidant enzymes were similar,and the activity increased with the increase of drought degree.3.The effect of dry heat stress on the chlorophyll content in the leaves of Acer truncatum leaves was obvious.The chlorophyll a was significantly lower in the middle and severe drought conditions at 40℃.The chlorophyll b and total chlorophyll content were the same,and reached the maximum at 25℃ The content of carotenoids increased with the increase of dry heat stress,and reached the highest at 40℃.Indicating that carotenoids as an antioxidant in the ingot maple by the severe stress to play an important role.4.The changes of net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular carbon dioxide(Ci),transpiration(Tr)and water use efficiency(WUE)were different in dry and heat stress treatments The The Pn,Gs and WUE reached the highest at 35℃ under sufficient water and moderate drought conditions,then decreased,and Ci and Tr reached the maximum at 25℃,and decreased with the increase of temperature.Under heavy drought conditions,Pn,Gs,Tr,Ci and WUE decrease with increasing temperature.The results showed that the non-stomatal factors played a dominant role in the decline of photosynthetic rate under moderate drought conditions.In order to keep the stomata closed and the transpiration rate was reduced,the leaves could not be absorbed by CO2,and the photosynthetic rate was decreased.5.The photochemical quantum efficiency(ΦPSII),photochemical quenching coefficient(qP)and electron transport rate(ETR)of the chlorophyll fluorescence parameters were changed under the condition of sufficient moisture and moderate drought.(P<0.05),and the photochemical quenching coefficient(qN)was significantly increased under the condition of severe drought at 40℃ which indicated that the light energy was dissipated in the form of heat,The photosynthetic linear electron transfer function decreased significantly,the Calvin cycle was inhibited,causing the use of ATP and NADPH decreased,the photosynthetic reaction mechanism was severely stressed. |
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