Research On The Response Mechanism Of Zamioculcas Zamiifolia Tubers In Drought Stress

Zamioculcas zamiifolia Engl.,a member of the family Araceae and is a tropical ornamental plant with extremely high ornamental value.Tubers are organs formed in its asexual reproduction,it may play an important role in the survial and reproduction of plants in arid environments.In order to explore the role of tubers in the drought stress of Z.zamiifolia,the responses of the tuber of Z.zamiifolia to drought stress were analyzed in order to provide reference for the study of the drought resistance mechanism of Z.zamiifolia.In this paper,the components of the tubers of Z.zamiifolia were determined,and the effects of different water conditions on the formation of tubers during the cutting process were studied,the water potential changes of the tubers and plant parts of Z.zamiifolia under drought treatment were studied.The photosynthetic response of Z.zamiifolia in the presence or absence of tubers was measured using a photosynthetic analyzer and measured changes in membrane lipid peroxidation,proline content,and electrolyte permeability,etc.,with water conditions.The main findings are as follows:1.At different stages,the water content is the main component of Z.zamiifolia tuber,and the un-germinated tubers?the tubers formed by cutting in two months are just in the pre-emergence stage?and the tuber water content of the three years mature plants are97.20%and 96.79%,respectively;In dry matter,the tuber starch content of mature plants was72.97?mg/g.DW?higer than that of neodes tuber55.76?mg/g.DW?.The soluble sugar content and the polysaccharide were low;The content of ash,protein,crude fiber and crude fat were all extremely low.2.Drought stress significantly inhibited the formation of the roots of cuttings of Z.zamiifolia,and the diameter of the tubers of the cuttings increased first and then decreased,increased by 71.38%from 20-50d,and decreased by 28.05%from 50-90d.The change of drought treatment was lower than that of the control,which was significantly different from the control.Drought stress severely inhibited the formation and elongation of roots,and inhibited the growth of tubers.Under water treatment,the roots of cutting showed a tendency of rapid increase.Within 20-40d,the number of roots increased by 93.22%,the length has increased by 98.17%.The tuber diameter of cuttings increased continuously and increased by 65.78%within 20-40d.The amplitude of changes in water treatment was lower than that of the control,which was significantly different from the control.Water cutting has a certain influence on the formation and elongation of roots,and at the same time inhibits the growth of tubers to a certain extent,drought stress has a greater impact.3.The root water potential of Z.zamiifolia gradually decrease with the depletion of soil moisture,and decreased by 0.40MPa compared with the control at 45 days.After rehydration began to rise,rehydration on the 15th day was 0.26MPa higer than the control.The root of Z.zamiifolia can use low water potential to enhance its water absorption capacity and improve the drought resistance of the plant;Leaf water potential and petiole water potential maintain a steady change trend under drought and rehydration conditions.The leaf water potential did not change much from that of the control,and some organs may provide water to the leaves during drought.The petiole water potential decreased by 0.13MPa compared with the control at 45 days,and rewatering was 0.04MPa higher than the control at the 15th day.The petiole water potential was higher than the leaf water potential,some organs provided enough water for the petiole and leaves during the drought;The tuber water potential decreased with the extension of drought stress,and decreased by 0.39MPa compared with the control at 45 days.After rehydration began to rise,rehydrated 15d higher than the control by 0.13MPa.The water potential of tubers was higher than that of the other three organs,and the ability of tubers to transport water was strong.Combining the trend of changes in leaf water potential,petiole water potential,and tuber water potential indicated that tubers played a major role in storing water during the growth of Z.zamiifolia.4.The net photosynthetic rate,stomatal conductance,intercellular CO2 concentration and transpiration rate of the leaf of Z.zamiifolia of tubers with and without tubers showed a decreasing trend with the prolongation of stress days,and began to increase after 30 days of rehydration.Tubers can reduce the decrease of the photosynthetic index value of the leaves of Z.zamiifolia,and delay and reduce the influence of drought stress on photosynthesis.The maximum photosynthetic quantum yield?Fv/Fm?values of the leaf of Z.zamiifolia of tubers with and without tubers had no obvious trend;The photochemical quenching?qP?decreased continuously under drought stress and increased after rehydration;Under drought stress,non-photochemical quenching?NPQ?showed a continuous rise,and then decreased after rewatering;The actual light quantum efficiency(?_PS?)increased first and then decreased.Tubershadlittleeffectonthemaximumphotochemicalquantum yield?Fv/Fm?,but it slowed down the damage caused by drought stress on PS?,delayed the defense mechanism of plant photoinitiation and the process of plant damage caused by drought stress.The contents of proline,malondialdehyde,and electrolyte permeability of the leaf of Z.zamiifolia of tubers with and without tubers showed an increasing trend with the prolongation of stress days,and they began to decline after rehydration on the 30th day.Tubers had significant effects on proline content and MDA content.Removal of tubers resulted in large accumulation of proline content and MDA content,but had little effect on electrolyte permeability.In summary,tubers can help plants resist drought stress by regulating the photosynthetic response of the leaves.At the same time,removal of tubers can cause damage to the plants.