| Because the large-scale cultivation technology of Schisandrae chinensis is not yet mature,excessive fruit load usually lead to small fruit,non-mature grains and leaf senescence,which is not conducive to the pursuit of high quality during the development of S.chinensis cultivation.In this study,’ Tieling-0401 ’ and ’ Zaohong ’ were used as the research objects,and three different load treatments were carried out on the two excellent lines.The treatment of Tieling-0401 ’ was T1(leaving 1 ear fruit),T2(leaving 2 ear fruit),CK2(not thinning fruit),and the treatment of ’ Zaohong ’ was Z1(leaving 1 ear fruit),Z2(leaving 2 ear fruit),CK1(not thinning fruit).The two superior strains of S.chinensis were treated with three different loads.The photosynthetic capacity,leaf anatomical structure,light damage defense ability and fruit quality were measured and analyzed.The main results are as follows :1.Diurnal variation of photosynthetic rate of leaves in S.chinensis under different loads showed a double peak curve.According to the difference of Pn,Ci and Gs,the phenomenon of photosynthetic ’noon depression’ was caused by non-stomatal limitation.According to the light response curve,the net photosynthetic rate of leaves in ’Zaohong’ decreased with loading amount increase.However,the net photosynthetic rate of treatment T2 in ’Tieling-0401’ was the highest,and CK2 was the lowest.These results indicated that the effects of different loads on the photosynthetic capacity of S.chinensis leaves were different under the same treatment.2.There was positive correlation between the light damage defense ability and fruit load of S.chinensis leaves.After strong light stress,the activities of antioxidant enzymes such as SOD,POD and CAT in leaves increased with the decrease of fruit load.TRo/CS,ETo/CS andΨo of’Zaohong’ decreased with the increase of fruit load,but ABS/RC,DIo/RC and TRo/RC increased with the increase of fruit load.These results showed that activity decrease of photosystem and ROS formation resulted in senescence of the leaves in the late stage of growth.3.The content of soluble sugar and titratable acid in ’Zaohong’ fruits decreased with the increase of fruit load,while the content of soluble sugar in ’Tieling-0401’ had no obvious change,and the content of titratable acid was the highest at T2.It can be concluded that there are cultivar differences in the response of S.chinensis fruit qualityunder the same treatment.In terms of the apparent quality of S.chinensis,the ear length,ear weight,fruit weight and fruit particle size showed a gradually increasing trend with the decrease of fruit load,indicating that the load treatment had obvious effect on the appearance quality of S.chinensis.The changes of schisandrin,schisandrol B,schisantherin A,deoxyschizandrin and schisandrin B in’Tieling-0401’ showed that T2 treatment was significantly lower than T1 and CK2 treatment.The content of schisandrin,schisandrol B,schisandrin B in ’Zaohong’ fruit increased with the increase of fruit load. |
