| This experiment investigated the effects of different temperature treatments(20/13°C,25/16°C,30/18°C)on the growth and flower bud differentiation of the 'zijiao'.In order to provide a theoretical basis for the study of chrysanthemum flowering induced by temperature.The main results are as follows:(1)The flower bud differentiation process of ?zijiao' was divided into nine periods: undifferentiated period,flower bud differentiation initiation period,total squama differentiation initial and final period,florets primordium differentiation initial and final period,corolla formation initial,middle and final period.The flower bud differentiation was started at 20/13 °C treatment and 25/16 °C treatment at sixth day,which was 3 days earlier than 30/18 °C treatment and CK treatment.The treatment at 20/13°C was the first to enter the initial differentiation of total squama,which was 3 days earlier than 25/16°C treatment and 30/18°C treatment,the total squama differentiation at 20/13 °C treatment and 30/18 °C treatment required 15 d,longer than 25/16 °C treatment for 3 days.The floret primordial differentiation of 25/16°C treatment and 30/18°C treatment was 6 days earlier than that of 20/13°C.The corolla formation at 25/16°C took 9 days,and the total length of flower bud differentiation was 42 d,30 days earlier than CK treatment.(2)In the process of flower bud differentiation,the enzyme activities(SOD,POD)in the leaves showed the same trend of increasing first and then decreasing.The SOD activities of different treatments peaked at the primordium differentiation stage.The primordium differentiation period of SOD activity at 30/18 °C was significantly higher than that at 20/13 °C and 25/16 °C(p<0.01).The POD activity at 20/13°C treatment was significantly higher than that at 25/16°C and 30/18°C(p<0.01).The POD activity at 30/18°C was significantly higher than that at 20/13.°C treatment(p<0.05).The content of soluble protein and soluble sugar showed the same trend of increase-decrease-increased,and the starch content showed a trend of decreasing first and then increasing.The soluble protein content at 30/18 °C was significantly higher than that at 25/16 °C(p<0.05).The soluble sugar content at 25/16 °C was significantly higher than that at 20/13°C(p<0.05).From the initiation period of flower bud differentiation to the differentiation stage of florets,the starch content at 20/13°C treatment,25/16°C treatment and 30/18°C treatment was not significant.The starch content at 20/13°C treatment was significantly higher than that at T3 during corolla formation.Treatment(p < 0.01).The contents of chlorophyll a,chlorophyll b and carotenoids all increased first and then decreased.The content of pigments in each treatment reached the peak in the primordium differentiation stage.The content of chlorophyll(a,b)in the primordium differentiation of floret was significantly lower than that at 25/16 °C and 30/18 °C(p<0.01),but the carotenoid content was treated at 25/16 °C.The difference in treatment at 30/18 °C was not significant.The chlorophyll a,chlorophyll b and carotenoid contents increased at the 25/16 °C treatment from the differentiation period of the total squama to the differentiation of florets.(3)The amount of heat required to complete the entire flower bud differentiation process under natural conditions is the effective accumulated temperature.The effective accumulated temperature required for flower bud differentiation at 20/13 °C and 25/16 °C was 787 days and 441 days,respectively,which was less than the heat required for CK treatment(1066 days).At the completion of differentiation,the plant height and crown width at 25/16°C treatment were significantly less than 20/13°C treatment(P<0.05),and the internode length was not significantly different from that treated at 20/13°C and 30/18°C.Plant height,crown width and internode length were all less than CK treatment under temperature treatment.The soluble protein and soluble sugar content at 25/16°C treatment was significantly higher than that at 20/13°C treatment and 30/18°C treatment(P<0.05).The starch content was significantly lower than 20/13°C treatment and 30/18°C treatment.(P<0.05),the difference in starch content from CK treatment was not significant.(4)Under the treatment of 25/16°C,the bud stage was 12 days and 3 days earlier than 20/13°C treatment and 30/18°C treatment,and the dew color period was 42 days earlier than CK treatment.The exposed period to full bloom period lasted 27 days,20 /13 °C,30/18 °C treatment initial flowering,full flowering period is close to CK treatment,25/16 °C treatment full bloom period earlier than 20/13 °C,30/18 °C treatment for 44 days.Under different temperature treatments,the plant height,crown width and internode length of 'zijiao' were significantly less than CK treatment(P<0.05),and the flowering rate decreased sharply. |
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