| As a kind of plant resource with great medicinal value,Paris spp.is a difficult reproduction?slow growth and lack of resources.The species of this genus is complex with large variations,and the different species are often complex and changeable,and the characteristics in different species often cross or overlap.The identification lines of various types are often vague,existing classification more confusion.This paper studied the anatomical structure and photosynthetic characteristics of three varieties of Paris polyphylla Smith in Shennongjia forest area,analyzed the differences in the morphological structure of their leaves and roots,and the ecological adaptability of their photosynthetic pigments and photosynthetic characteristics.The main results were showed that:The main results showed that:1.The morphological index:The lengths of leaves of three varieties of Paris polyphylla Smith are between 9 and 16cm.The lengths of leaves of replants of Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell are significantly longer than those of Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li and Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz..The difference between the latter two is not significant;The width of the leaves of three varieties is significantly different,ranging from 2-7cm;the leaf length/width of the Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li is significantly higher than the Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell and Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.;Leaf perimeter,leaf area and perimeter/leaf area were significantly different among the three variants.The leaf perimeter and leaf area of Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell were the largest,and the perimeter/leaf area was the smallest.From the correlation analysis of leaf morphological characteristics,leaf area was positively correlated with leaf length?0.956**?,leaf width?0.969**?,leaf length×width?0.984**?and leaf circumference?0.974**?,and was significant negative correlation with the perimeter/area?-0.882**?.The correlation coefficient between leaf perimeter and leaf width was0.995**,indicating that leaf area is most likely to be reflected by leaf length×width.The leaf perimeter can be best reflected by the leaf length.The number of adventitious roots of the three varieties of Paris polyphylla Smith is between 16 and 33,and the total length is between 49 and 134cm.The root system of Euphorbiaceae is dominant both in terms of quantity and overall length.The three variants have underdeveloped root systems and are fewer in number and shorter in length.2.The anatomical structure index:Through observation the slices,the leaves of the three variants of Paris polyphylla Smith are typical heterogeneous leaves,composed of epidermis,mesophyll and veins.The size and thickness of each tissue structure are quite different.The leaf thickness is between 724.25 and 854.25?m.The three variants have obvious differences between the palisade tissue and the spongy tissue.However,the ratio of the palisade tissue/sponge tissue is between 0.14 and0.18,which is much less than 1,indicating that the three varieties of Paris polyphylla Smith are shade plants.The proportion of leaf sponge tissue is large and the palisade tissue is underdeveloped.There are differences in the vascular bundles of the midvein of the three-variant species.And Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell had greater the thickness of the palisade tissue,the thickness of the sponge tissue,and the thickness of the main vein,and higher the rate of water transport;the adventitious roots of the three varieties of the Paris polyphylla Smith are composed of epidermis,cortical and vascular cylinders.And the root diameter were between2209.25-3328.50?m,and there are significant differences in root diameter,cortical thickness,and vascular bundle between different species.The thickness of the cortex of Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li?116.25?m?was significantly higher than that of the other two varieties.The tube diameter of the posterior xylem of Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.was the smallest?84.50?m?,which was significantly lower than that of the other two varieties.Both the diameter of the root system and the diameter of the vascular cylinder and the thickness of the cortex of Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell were relatively large,indicating that the water delivery rate of the root system of the Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell was relatively large.3.The photosynthetic pigments index:The total chlorophyll content of three varieties of Paris polyphylla Smith leaves was between 0.61 and 1.23mg/g,and Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell was the highest,indicating that the photosynthetic activity of Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell is relatively strong.At the level of P<0.05,there were significant differences between chlorophyll a and chlorophyll a+b of the three varieties,and the chlorophyll b and carotenoids of Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell were significantly higher than those of the Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li and Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz..The highest content of chlorophyll a,chlorophyll b and carotenoids in the Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell is relatively high,and Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li and Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.is relatively low,indicating that the Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell is more effective protecting the plant in excessive light or UV radiation;Chlorophyll a/b value was between 1.23 and 2.13,the Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li was the largest,the Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell was the smallest,at P<0.05 level,there is no significant difference between the Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li and Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.,Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell significant less than the former two,it proves that the most adaptable to the weak light environment is Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell.4.The diurnal variation of photosynthesis index:The diurnal variation of photosynthetic of three varieties of Paris polyphylla Smith showed a double-peak curve,which peaked at 11:00 and 14:00,and the midday depression of photosynthesis activity from 12:00 to 13:00.Under early and late low light conditions,the utilization of light energy was lower in Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li and Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.,and the photosynthesis of Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell was the strongest;The diurnal variations of transpiration rate and stomatal conductance were similar to the net photosynthetic rate.The diurnal variation of intercellular CO2 concentration was opposite to net photosynthetic rate,but the change range was relatively flat;The daily change curve of water use efficiency had no obvious regularity,but overall,the highest number of replants was Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell,and Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li and Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.was slightly lower,indicating that the water use efficiency of the Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell is higher under water shortage conditions;The analysis of the daily change of the stomatal limit value shows that the photosynthetic midday depression of three varieties of Paris polyphylla Smith is caused by the non-stomatal limitation;The photosynthetic rate of three varieties of the repetitive plants is analyzed.The analysis of relationship between the ecological factors found that the net photosynthetic rate was significantly correlated with the light intensity and significantly,correlated with the temperature.5.The light response curve index:The light saturation points range from 500-900?mol.m-2.s-1 for three species of Paris polyphylla Smith,and the lowest for Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.,the highest saturation point for Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell is the highest,and the adaptability to strong light is better.The light compensation point ranged from4.707-6.538?mol.m-2.s-1,and the minimum was the Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.,the adaptability to weak light was slightly stronger,and the utilization rate of weak light was higher.The maximum net photosynthetic rate,dark respiration rate and apparent quantum efficiency were as follows:Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell(2.335?mol.m-2.s-1,0.33?mol.m-2.s-1,0.057?mol.m-2.s-1),Paris polyphylla Smith var.stenophylla f.latifolia?Wang et Tang?H.Li(2.387?mol.m-2.s-1,0.497?mol.m-2.s-1,0.09?mol.m-2.s-1),ParispolyphyllaSmithvar.yunnanensis?Franch.?Hand.-Mazz.(2.333?mol.m-2.s-1,0.497?mol.m-2.s-1,0.126?mol.m-2.s-1).Based on the analysis of the photosynthetic parameters of three variants,it was found that Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell has a stronger ability to adapt to strong light,and Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.has better ability to adapt to weak light.6.The correlation between the net photosynthetic rate and the characteristic parameters of leaves index:A comprehensive analysis of the correlation between the net photosynthetic rate and leaf characteristic parameters of three varieties of Paris polyphylla Smith leaves found that the relationship of except net photosynthetic rate with leaf thickness and chlorophyll a/b was significant,the leaf area,thickness of palisade tissue,thickness of sponge tissue,palisade tissue/sponge thickness,chlorophyll a,chlorophyll b,chlorophyll a+b and net photosynthetic rate were not significant,indicating that the size of leaf area and the content of chlorophyll could not be used as criteria for judging the intensity of photosynthesis of polyphylla.A comprehensive analysis of the morphological,anatomical and photosynthetic characteristics of the three varieties of Paris polyphylla Smith plant showed that the leaf area can be best reflected by the leaf length×width,and the leaf perimeter can be best reflected by the leaf length.The adventitious roots of the plant are underdeveloped?small quantity and short length.However,the root system of Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz is relatively well developed in the three varieties.Paris polyphylla Smith var.altiba H.Li et R.J.Mitchell has a strong photosynthesis,high light energy utilization?higher water use rate and strong adaptability to strong light and low light,at the same time,it can effectively protect itself from excessive light intensity or ultraviolet radiation.In addition,Paris polyphylla Smith var.yunnanensis?Franch.?Hand.-Mazz.has a certain adaptability to weak light. |
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