Effects Of Three Plant Growth Regulators On The Growth And Development Of Hemerocallis Middendorfii

Hemerocallis middendorfii is a perennial flower of the Hemerocallis L.,with a well-developed root system,beautiful plants,brilliant flowers,sloppy management,and strong practicality,and is a traditional gardening material.In this study,three different concentrations of plant growth regulators(CCC,MT,GR24)were applied by foliar spraying,and the dynamic changes of physiological and biochemical indexes were measured and comprehensively analyzed and evaluated in order to screen out the best plant growth regulators and concentrations,improve the ornamental value and promote plant growth and development,and initially discussed the effect mechanism of three plant growth regulators on the the mechanism of the effect of three plant growth regulators on H.middendorfii was initially explored.The main results are as follows.(1)In terms of growth characteristics,the three plant growth regulators can have a certain regulatory effect on the growth form of H.middendorfii under suitable concentrations.Three kinds of plant growth regulators can increase the number of leaves and leaf width of H.middendorfii,among which CCC treatment will reduce the plant height,crown width and leaf length of H.middendorfii,making the plant dwarf and compact,MT and GR24 will improve the plant height,crown width and leaf length,making the plant tall and majestic.The study showed that 300mg/L CCC treatment was the best for dwarf treatment,and 30mg/L MT and 0.3mg/L GR24 treatment were the best for growth promotion.(2)In terms of root development,the appropriate concentrations of the three plant growth regulators could promote the root indexes of H.middendorfii.Among them,30mg/L MT had better effect in promoting the root length and surface area of plant,0.3mg/L GR24 had the best effect in improving the number of root nodes of the plant,and 300mg/L CCC and 0.3mg/L GR24 had little difference in improving the root vigor.(3)In terms of photosynthetic characteristics,all three plant growth regulators at suitable concentrations could improve chlorophyll a,chlorophyll b and total chlorophyll content,increase stomatal conductance,and enhance net photosynthetic rate of the plants at different degrees.In the treatment of 300mg/L CCC,30mg/L MT and 0.3mg/L GR24,chlorophyll content,Pn,Gs and Tr increased significantly and Ci decreased significantly.(4)In terms of physiological characteristics,the three plant growth regulators could have certain effects on various physiological indexes of H.middendorfii at suitable concentrations,and all significantly reduced the relative conductivity,MDA content and proline content of plant leaves,and significantly increased the relative water content,soluble sugar,starch and soluble protein content.In terms of plant growth regulator types,CCC had certain advantages in improving the relative water content and soluble sugar content of plant leaves,MT had certain advantages in improving the starch content of leaves,and GR24 had certain advantages in reducing the relative electrical conductivity,MDA content and proline content of leaves and improving the soluble protein content of leaves.In terms of plant growth regulator concentration,the best treatment effect was achieved under 300 mg/L CCC,30 mg/L MT and 0.3 mg/L GR24 treatment.(5)In terms of endogenous hormones,all three plant growth regulators could have certain effects on the endogenous hormones(IAA,GA and ABA)in the leaves of H.middendorfii 450 mg/L CCC,30 mg/L MT and 0.3 mg/L GR24 treatments significantly increased the IAA and GA contents in the leaves of plant,among which 30 mg/L MT treatment had the highest leaf IAA and 0.3 mg/L GR24 treatment.The leaf IAA and GA contents were significantly increased under 30mg/L MT treatment and 0.3mg/L GR24 treatment,and the leaf ABA contents were significantly decreased under 300mg/L CCC and 30mg/L MT treatments with little difference.(6)In terms of carbon and nitrogen metabolism,the three plant growth regulators could have certain effects on the carbon and nitrogen metabolism indexes of H.middendorfii at suitable concentrations.The three plant growth regulators can significantly increase the total carbon and nitrogen content of the leaves of H.middendorfii,among which the total carbon content of the leaves under 30 mg/L MT treatment was the largest,and the total nitrogen content of the leaves under 300mg/L CCC treatment was the largest.In terms of carbon to nitrogen ratio,the carbon to nitrogen ratio increased under 150 mg/L CCC,30 mg/L MT and 0.3 mg/L GR24 treatments,and the largest carbon to nitrogen ratio was found under 30 mg/L MT treatment.In terms of carbon and nitrogen metabolism enzymes,the nitrate reductase and amylase activities of the leaves of plant were significantly increased under 300 mg/L CCC,30 mg/L MT and 0.3 mg/L GR24 treatments and the differences were not significant.The above results showed that the three plant growth regulators could improve the stress resistance,delay senescence and optimize the growth and development of Hemerocallis middendorfii.CCC could make the plant dwarf and compact,MT and GR24 could make the plant tall and majestic.