Study On The Influence Of Enhanced UV-B Radiation On The Growth And The Endogenous Hormone Contents Of Tomato (Lycopersicon Esculentum Mill.) Seedlings

The atmosphere caused by human activities,thinning of the ozone layer,caused by a direct radiation has become a major global environmental problems.At present, domestic and foreign scholars on the biological effects of radiation has done extensive research,but the subjects are more concentrated in the area of cultivation of certain crops and ecosystems,research on vegetables less involved and the results there are certain differences.In this paper,Tong-hui as the material of tomato seedlings in the natural light intensity under the conditions imposed are artificial 0.46w/m²(T1) and 0.6w/m²(T2) of two sets of radiation,daily 7h,to the natural radiation 0.4w /m² for the control group(CK).Study of radiation enhanced the growth of tomato seedlings and the effects of metabolic physiology and biochemistry,with a view to cultivation technology for tomato resistance to lay a certain foundation for the study.The purpose of this study to obtain the following results:(1) In the low-intensity(0.46w/m²) and high intensity(0.6 w/m²) of UV-B radiation conditions,Tong-hui of the growth of tomato seedlings significantly inhibited,as follows:dwarf plants,stem diameter thinning,leaf area become smaller,and with curled leaves,brown spot symptoms;the degree of its suppression of the cumulative amount of radiation is proportional to.UV-B radiation more intense and by the inhibition of plant deeper;two dealt with in the root activity has always been lower than that of control,and the more intense radiation,the more weak root activity;(2) In contrast to the two to deal with than the increase in proline content that enhanced UV-B radiation can stimulate proline in leaves of tomato seedlings synthesis, thereby enhancing the capacity of osmotic adjustment,and the greater the radiation intensity,the stronger the infiltration capacity,but the The increase in content to some extent alleviated the damage of tomato seedlings.(3) At different UV-B radiation,SOD,POD and CAT activity of three enzymes have shown to deal with than the control,and high-intensity(0.6 w/m²) deal with than low-intensity activity(0.46w/m²) to deal with.This may be due to tomato seedlings in the UV-B radiation under adversity,in the body have a large amount of O₂^- and H₂O₂ and other reactive oxygen species,leading to three of the activity of protective enzymes,thereby reducing the reactive oxygen species damage to seedlings.(4) As the content of MDA in the UV-B radiation intensity increases,that is,the more intense radiation,the greater the content.Reflects the intensity of UV-B radiation enhancement of the tomato seedling leaves increased membrane lipid peroxidation.(5) Tomato seedlings IAA,GA₃,ZR content with radiation to enhance and extend the decline in time;and ABA content with radiation to enhance and increase the extension of time,with the result that IAA/ABA,GA₃/ABA and ZR/ABA's ratio also decreased,although the IAA,GA₃,ZR content in the lower and the increase in ABA content in a certain degree of UV-B radiation enhanced to adapt to,but ultimately inhibit the growth of tomato seedlings.