| Schisandraceae,belonging to Illiciales of the dicotyledonous Magnolidea,is rich in nutrients and pharmacological activities,with high economic value and large market demand.It includes two genera,Schisandra Michx.and Kadsura Kaempf.ex.Juss.Schisandra sphenanthera is a perennial deciduous woody vine of the genus Schisandra.Kadsura coccinea is an evergreen woody vine of the genus Kadsura.At present,there are few studies on the intergeneric grafting interaction of Schisandraceae plants.In this study,seedlings of Schisandra sphenanthera(Ss)and Kadsura coccinea(Kc)were used as rootstocks for intergeneric distant grafting using the approach grafting.The intergeneric grafting combinations were set as the experimental groups(Ss/Kc,Kc/Ss),and the self-grafting combination was set as the control groups(Ss/Ss,Kc/Kc).The effects of different rootstocks on the growth of scion stems and leaves,as well as on the apparent morphology,anatomical structure,photosynthetic characteristics and endogenous hormones were preliminarily explored from three aspects of morphology,cytology and physiology and biochemistry,so as to provide a theoretical basis for the breeding of rootstocks of Schisandraceae.The main results were as follows:1.Different rootstocks have significant effects on the morphological development of scions.The shoot growth,stem diameter and leaf area of Ss/Kc were significantly higher than those of Ss/Ss,which increased by 13.75%,18.59%and 18.35%respectively.The leaf shape index is close to 1,and the leaf shape is nearly elliptic.The growth of new shoots and stem diameter of Kc/Ss was inhibited,which decreased by 21.6%and 12.3%respectively compared with Kc/Kc.The leaf shape index is significantly improved,the leaf shape is nearly slender,and the apex is gradually pointed.2.Different rootstocks have significant effects on the microanatomy in the stem and leaf of scions.Compared with Ss/Ss,Ss/Kc exhibited increases in the main vein thickness,lower epidermis thickness,palisade tissue thickness,the ratios of palisade tissues to spongy tissues and tightness degree of leaf tissue structure of 21.76%,22.71%,45.43%,48.09%,and 39.8%,respectively,while loose degree of leaf tissue structure was decreased significantly by 15.91%.The xylem area,cortex area and pith area of the stems are increased significantly,while the xylem rate,pith rate and cortex rate are increased by 22.56%,33.51%and 37.52%,respectively.All the indexes related to stress resistance are increased to a certain extent.On the 50th day after grafting,compared with Kc/Kc,the ratios of palisade tissues to spongy tissues and tightness degree of leaf tissue structure of Kc/Ss were significantly increased by 88.73%and 63.03%,while the xylem rate,cortex rate and vessel rate of stem were significantly decreased by 50.28%,53.9%and 32.6%,respectively,inhibiting the lignification process of the stem.3.Different rootstocks have significant effects on stomatal characteristics,chlorophyll content and photosynthetic capacity of scions.Compared with Ss/Ss,Ss/Kc had significantly increased stomatal area and aperture by 57.87%and 56.08%,respectively,as well as significantly increased chlorophyll a content.Net photosynthetic rate,light compensation point,dark respiration rate,and apparent quantum efficiency were all significantly increased,of which dark respiration rate was significantly increased by 51.20%,enhancing the utilization of weak light and strong light by grafted seedlings,and increasing the accumulation of carbohydrates.Compared with Kc/Kc,the stomatal area of Kc/Ss was significantly increased from day 50 to day 70 of grafting.However,the contents and total contents of chlorophyll a and b were significantly lower than Kc/Kc,and the maximum net photosynthetic rate and dark respiration rate were significantly decreased by 37.30%and 21.10%,respectively.Their photosynthetic capacity and utilization of weak light were decreased.4.Different rootstocks have significant effects on the soluble sugar and soluble protein content in the stem and leaf of scions.Compared with Ss/Ss,the contents of soluble sugar and soluble protein in stems of Ss/Kc increased significantly,which were 1.06 and 1.95 times higher than those of Ss/Ss,respectively,which promoted the metabolic activity of the stems and accelerated the process of interface healing and seedling development.Compared with Kc/Kc,the soluble sugar content in leaves and stems of Kc/Ss decreased by 17.50%and 9.87%respectively,and the content showed a continuous downward trend.The content of soluble protein in leaves increased significantly by 9.11%.5.Different rootstocks have significant effects on the hormone content and distribution in the stem and leaf of scions.On the 50th day after grafting,the contents of ZR and GA3 in leaves of Ss/Kc both reached their peak values,which were 1.77 times and 1.44 times as much as those of Ss/Ss.At the same time,the value of(IAA+ZR+GA3)/ABA was also increased.Compared with Ss/Ss,the value of IAA/ABA was significantly increased by 61.94%on the 50th day of grafting.The growth potential of the grafted plant was enhanced,and the leaf area was significantly increased.The new shoot grew rapidly and the stem tissue differentiation was accelerated.Compared with Kc/Kc,the contents of IAA,ZR,and GA3 as well as the value of(IAA+ZR+GA3)/ABA in leaves and stems of Kc/Ss were decreased significantly,while those of IAA,ZR,and GA3 were decreased by 54.08%,68.97%,and 62.91%,respectively.This inhibited the longitudinal and transverse growth of new shoots of scion,and affected the growth,development,and differentiation process of plants.6.Different rootstocks have significant effects on superoxide dismutase activity and malondialdehyde content in the stem and leaf of scions.Compared with Ss/Ss,the superoxide dismutase activities in leaves and stems of Ss/Kc were significantly higher than those in Ss/Ss on the 50th day after grafting,increasing by 10.27%and 12.57%,respectively.At this time,the plant growth was in the stage of significant increase in leaf area and rapid growth of new shoots,and the communication between scion and rootstock was strong.Malondialdehyde content in leaves and stems was significantly lower than Ss/Ss,and decreased by 73.80%and 64.74%at the 50th after grafting,respectively.Compared with Kc/Kc,the superoxide dismutase activity in leaves and stems of Kc/Ss was decreased,and the malondialdehyde content was increased,thus affecting the antioxidant and stress resistance abilities of stems and leaves of scions. |
