| Rhododendron is a famous flower in the world and one of the ten famous flowers in China.Rhododendron simsii is a native species of Rhododendron genus.It is widely distributed in Guizhou.It has a beautiful plant type,long flowering period,large flower volume and fresh flowers.It is a typical local ornamental plant;Pinus massoniana Lamb is the most planted tree species in low-altitude areas in Guizhou Province.Rhododendron simsii is often associated with Pinus massoniana in the wild environment,forming a unique Masson Pine-Rhododendron landscape community,and the growth of Rhododendron simsii under the Pinus massoniana forest.Better,more colorful and Both are typical mycorrhizal plants.In this paper,the annual Rhododendron mycorrhiza seedlings treated with CK(non-inoculation),D(mixed inoculation with rhododendron mycorrhizal fungi),DM(mixed inoculation with rhododendron mycorrhizal fungi and Pinus massoniana)were used as test materials,Use mild water and humidity(W185%-95%),normal moisture W(75%-80%)mild drought T1(60%-65%),moderate drought T2(50%-45%)and severe Five water gradients of drought T3(35%-40%)were used to set the test plan to study the changes of rhododendron mycorrhizal growth physiology,endogenous hormones and photosynthetic indicators under different water conditions,and to clarify the growth of rhododendron root seedlings under different water conditions.It provides a theoretical basis for water management in the cultivation and maintenance of Rhododendron simsiin.The main results of this study are as follows:1.Inoculate the aseptic seedlings of Rhododendron simsiin with the test mixed bacteria,and measure the infection rate of Rhododendron simsii root with acetic acid staining after 280 days of normal curing.The results show that the difference in infection of Rhododendron simsii root by different mixed inoculation treatments is very significant(P < 0.01),DM(51.2%)> D(32.3%)>CK(7.11%).2.Under different water conditions,inoculation of mixed fungi significantly increased the height and ground diameter of Rhododendron simsii seedlings.The growth of Rhododendron simsii seedlings under different mixed inoculation treatments under the same water gradient and the same inoculation treatment under different water gradients has certain differences.DM treatment performed best under T1 moisture conditions.3.Under different water gradients,the root vigor of Rhododendron simsii seedlings under mixed inoculation treatment increased,and the root vigor of inoculation treatment under T2 water condition increased significantly.The root activity of Rhododendron simsii under DM inoculation treatment increased by123.93% compared with CK treatment.Maintain higher root vitality of Rhododendron simsii root system to absorb more water from the soil.Under the T3 water treatment,the free proline,soluble sugar,and soluble protein content of the leaves of the inoculated seedlings increased significantly compared with CK.The inoculated treatment used osmotic adjustment to alleviate the pressure of water shortage environment,so that the plants can still survive under severe water shortage conditions.Maintain their own vitality;under different water conditions,the MDA content of inoculated Rhododendron simsii is always higher than that of CK treatment,and the enzyme activities of SOD,CAT,POD are also much higher than that of CK seedlings,especially under T3 water treatment,mixed inoculation treatment can improve The enzyme activity of Rhododendron simsii leaves eases or eliminates the pressure caused by water stress,making Rhododendron simsii better adapt to different soil water environments.4.Under different water gradients,the endogenous hormones of Rhododendron simsii change significantly,and the inoculation treatment has different effects on different endogenous hormones.Mixed inoculation treatment significantly increased the content of IAA in the leaves and roots of Rhododendron simsii.The difference between T3 water treatment and CK was particularly significant.Inoculated Rhododendron simsii seedlings could synthesize more IAA to induce the growth of lateral roots,increase the root absorption area,and increase the life activity of Rhododendron simsii roots.To increase the growth cover ability of Rhododendron simsii in different water environments;the ABA content of inoculated seedlings tended to be basically stable under different water gradients,except for W1 water,the ABA content of inoculated Rhododendron simsii leaves was lower than that of CK treatment,the difference was significant(P <0.05),But under severe water shortage treatment,the ABA content of mycorrhizal seedlings increased more than that of CK seedlings,and the inoculation treatment was more tolerant to the water shortage environment;under different water conditions,the content of GA3 content in the leaves and roots of Rhododendron simsii rhizome tended to change Stable,and the GA3 content of the inoculated leaves is always lower than that of CK treatment,the difference is very significant;under different water gradients,the Rhododendron simsii responds to different water environments through the synergistic effect of hormones,and the ratio of IAA / ABA in mixed inoculation treatment is higher than that of CK treatment As the soil moisture decreases,the IAA / ABA ratio decreases,and the IAA / ABA ratio decreases less than CK;ZR / ABA,(IAA + ZR + GA3)/ABA also produce Should change to improve the ability of azaleas on water use,different and better water environment.5.Mixed inoculation treatment can increase chlorophyll content,photosynthetic characteristic parameters and chlorophyll fluorescence parameters of Rhododendron simsii.Under mild water and wet environment,the chlorophyll content of CK treatment decreased,and the inoculation treatment was the opposite.The chlorophyll content of CK treatment gradually decreased in dry environment,but the chlorophyll content of inoculation treatment increased under mild and moderate drought stress;Under stress,the net photosynthetic rate,transpiration rate,and stomatal conductance of CK treatment showed a gradual downward trend and the decrease of CK treatment was greater than that of inoculation treatment.The intercellular CO2 concentration gradually increased and the value of intercellular CO2 concentration of CK treatment was greater than that of inoculation treatment;light Under high water and wet environment,the Fm,ΦPSⅡ,q P,ETRm and α values of each treatment decrease,Fo value of CK treatment increases D and DM treatment decreases,Fv / Fm of CK and D treatment increases,DM treatment does not change much;water shortage environment Under the condition of increasing drought,the values of Fv / Fm,Fv / Fo,PSⅡ,NPQ,q P,ETRm,and α of CK treatment all decreased,while the inoculation treatment first increased and then decreased(except α and NPQ).Through analyzing the growth physiological indexes of Rhododendron simsii seedlings under different water gradients,it is concluded that the inoculation treatment is generally better than the non-inoculation treatment.Different water gradients have different effects on the various indicators of Rhododendron simsii.Take a comprehensive view of the DM treatment under soil T1 moisture conditions It has the most obvious effect on the growth of Rhododendron simsii. |
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