Different Roles Of Tobacco Glandular And Non-glandular Trichomes In Response To Cadmium Stress

Cadmium is a heavy metal pollutant with great environmental damage,which will have a serious impact on plant growth and development and physiological and biochemical processes.As a specialized structure of plant epidermal cells,trichomes play an important role in plant-environment interaction.In present work,non-glandular tobacco T.I.1112 and glandular tobacco T.I.1068 were used to study the difference between glandular and non-glandular trichomes in response to cadmium(Cd)stress.Study the tolerance of T.I.1068T.I.1112 to cadmium stress,by observing the growth of two tobaccos under cadmium stress.By using microscope to study the development of trichomes under cadmium stress of T.I.1112 and T.I.1068.To study the changes of elemental composition in glandular trichome secretion under cadmium stress,and to detect the elemental composition and content of T.I.1068 glandular trichome secretion by SEM-EDX.In order to study the difference of cadmium content between T.I.1068 and T.I.1112 under cadmium stress,the total Cd content in tobacco leaves and the secreted Cd on leaf surface of T.I.1112 and T.I.1068 were detected byInductively Coupled Plasma Optical Emission Spectrometry(ICP-OES).These results indicated that glandular trichomes play more important role in improving tobacco tolerance to Cd by excluding toxic Cd outside the plant.The main findings are as follows:1.High concentration cadmium and low cadmium stress on different concentrations of secreted tobacco T.I.1068 and non-secretory tobacco T.I.1112,these results show that Long-term cadmium stress inhibited the growth and development of TI1068 and TI1112.Different concentrations of cadmium stress inhibited the growth of two tobaccos.The higher the cadmium stress concentration,the more serious the inhibition of tobacco growth,and the same cadmium stress concentration on TI1112.Growth inhibition is higher than TI1068.Under short-term high concentration of cadmium stress,the differences of cadmium tolerance tolerance between T.I.1068 and T.I.1112 were mainly compared by the survival time of tobacco.The survival time of T.I.1068 was much longer than that of T.I.1112 under the same concentration of high cadmium stress.It can be concluded that the secreted tobacco T.I.1068 is more tolerant to cadmium stress than the non-secreted tobacco T.I.1112.2.T.I.1068 is a secretory type of tobacco.The trichomes are composed of long-stem secreted and short-stem secreted type;T.I.1112 is a non-secretory type of tobacco,and the trichomes are mainly composed of non-secretory type and short-stem secretory tobacco.Cadmium stress was applied to T.I.1068 and T.I.1112.It was found that cadmium stress affected the occurrence of tobacco gland trichome in T.I.1068 and T.I.1112,and the glandular trichome density increased,but the glandular trichome type remained unchanged.Different concentrations of cadmium stress had different effects on the trichomes of T.I.1068 and T.I.1112.The density of two tobacco glandular glands increased with the increase of cadmium stress concentration.Moreover,under the same concentration of cadmium stress,the density of tobacco gland trichome increased with the increase of stress time.The longer the stress time,the greater the density of tobacco gland trichome.3.X-ray energy dispersion analysis of the glandular trichome secretion of secreted tobacco T.I.1068,detecting the elemental composition and element content of glandular trichome secretion,it was found that cadmium signal was detected in glandular trichome secretion after cadmium stress,and the higher the cadmium content in glandular trichome secretion with the increase of cadmium stress concentration.Under the same concentration of cadmium stress,the content of cadmium in glandular trichome secretion increased with the treatment time.It can be concluded that secretory glandular trichome can be used as a channel to excrete cadmium in tobacco.4.Inductively coupled plasma spectroscopy(ICP-OES)analysis of leaves and leaves of secreted tobacco TI1068 and non-secretory tobacco TI1112 showed that cadmium stress increased the leaf and leaf cadmium content of TI1068 and TI1112 under cadmium stress.The concentration of cadmium stress increased,but the absolute content of cadmium in leaves and the ratio of leaf surface to total cadmium in leaves were different.Under the same concentration of cadmium stress,the absolute content of cadmium in TI1068 was significantly higher than that in TI1112,and the difference was more obvious with the increase of cadmium stress concentration,and the ratio of leaf cadmium content to leaf cadmium was much higher than that of leaf cadmium.TI1112.Under the same concentration of cadmium stress,the cadmium content in tobacco leaves and leaves accumulated with time.However,the absolute content of leaf cadmium in T.I.1068 and the ratio of leaf cadmium to total cadmium in leaves are greater than T.I.1112,and will not change with increasing stress time.These results indicated that glandular trichomes play more important role in improving tobacco tolerance to Cd by excluding toxic Cd outside the plant.