Study On The Anatomy Of Male And Female Plants And Their Differences In Drought Resistance Of Salix Microstachya Var. Bordensis

Salix microstachya var.bordensis is widely distributed in the edge of sand dunes and low hilly land in Northeast China and Inner Mongolia.It is an important wind resistant and sand fixing plant in Hunshandake Sandy Land.Its natural regeneration is mainly sexual reproduction,and the rate of seedling emergence is high,but the survival rate of the seedlings is very low in the next year and the number of Salix microstachya var.bordensis in the natural population is too large.The effects of environmental factors such as soil moisture,temperature,light and sand burial depth on Seed Germination of Salix microstachya var.bordensis were studied in this paper.By comparing the anatomy of vegetative organs between male and female plants of Salix microstachya var.bordensis,their structural differences in sex and adaptability to habitats were compared.Setting 4 concentration gradient PEG solutions and 3 stress time gradients were used for drought stress,and the physiological indexes of Salix microstachya var.bordensis and male plants were compared under different stress treatments.The results are as follows:(1)The effects of indoor environment factors on the germination characteristics of Salix microstachya var.bordensis seeds showed that the soil water content suitable for the germination of Salix microstachya var.bordensis seeds was 6-25%,and 16% of the soil water content made the seed germination rate reach the highest.The optimum germination temperature of the seeds of the Salix microstachya var.bordensis was 25-30 degrees C,and the temperature at 25 C was the most suitable for the seed germination,and the light had no obvious restriction or promotion effect on the germination of the Salix microstachya var.Bordensis.The sand burial thickness suitable for the emergence of small red willow was 0-0.1cm,and the seedling emergence rate was the highest without sand and soil coverage.With the increase of sand burial thickness,the emergence of seedlings showed a significant decline trend.The dormancy period of the Salix microstachya var.Bordensis seeds is about 51 days,and the germination time is very short.(2)The vegetative organs of the roots,stems and leaves of the female and male plants of the Salix microstachya var.Bordensis were dissected to show that: the female plants and the male plants have some characteristics of the dry plants,and the drought resistance of the female plants is stronger.The difference of the vegetative organs of the female and male roots is that the cork layer of the female is thicker than the male,and the thickness of the epidermis,periderm and secondary vascular tissue part of the female is slightly larger than that of the male plant.The difference of the vegetative organs of the female and male stems of the Salix microstachya var.Bordensis,and male plants showed that there was no obvious difference in the thickness of the epidermis and cortex between the female and the male,and the female plants were obviously larger than the male plants in the thickness of the pericrp,the thickness of the xylem and the density of the ducts.The differences in the vegetative organs of the female and male leaves are: the thickness of the upper and lower epidermis cells,the width of the lower epidermis cells,the thicker horny layer,the thicker palisade tissue and the more developed veins,and the difference in the width of the upper epidermis and the thickness of the stratum corneum of the Salix microstachya var.Bordensis plant is not obvious in sex.(3)The effects of drought stress on the physiological indexes of the female and male plants of the Salix microstachya var.bordensis were simulated as follows: the stress conditions were fixed with the same sex,and the changes of the physiological indexes of the female and male plants with the stress degree were: the relative water content of leaves(RWC)decreased in the PEG;chlorophyll content,superoxide dismutase(SOD)activity,peroxidase(POD)activity,catalase(CAT)activity and root activity increased first and then decreased.Soluble sugar content increased first,then decreased and then increased;soluble protein content,PRO content and MDA content showed an upward trend.When setting stress conditions for the same stress level and time,the differences of physiological indexes between female and male plants were: RWC content,MDA content and root activity had no significant difference.Chlorophyll content and soluble sugar content were significantly different;soluble protein content,PRO content,SOD activity,POD activity and CAT activity of female plants were significantly higher than those of male plants;the POD activity of female plants was slightly largerthan that of male plants under no stress solution,and the CAT activity of female plants was significantly higher than that of male plants.The male and female plants in RWC content,chlorophyll content,soluble sugar content,soluble protein content,SOD activity,PRO content and root activity were the same.In summary,the change of all physiological indexes indicated that the female plants of Salix microstachya var.Bordensis.