| This study was conducted from 2013-2014 in Experimental Farm of Shandong Agricultural University and State Key Laboratory of Crop Biology. Two hybrids Zhengdan 958(ZD958) and Denghai 605(DH605) were used in 2013 and 2014. The experiment was to study the effects of spraying 6-BA on grain yield physiological characteristics of summer maize after waterlogging at three- leaf stage(V3) and six- leaf stage(V6), hoping to provide the corresponding agronomic regulation and provide theoreticalrefererces for anti-waterlogging cultivation of summer maize. The results as follows: 1. Effects of 6-BA on grian yield of summer maize after waterloggingGrain yield decreased significantly after waterlogging. Spraying 6-BA after waterlogging can help relieve the decline of the grain yield. The yields of maize hybrid DH605 in treatments of V3-6 and V6-6 were 15.57% and 12.39% lower than those of the ck, V3-6-T and V6-6-T were 15.57% and 12.39% higher than V3-6 and V6-6 respectively.Yields of ZD958 were lower by 30.39% and 21.39% after waterlogging;V3-6-T and V6-6-T were 20.05% and 15.32% higher than V3-6 and V6-6 respectively. Spraying 6-BA after waterlogging also affected the yield components of summer maize. Spraying 6-BA after waterlogging can help relieve the decline of grains per ear. Furthermore, spraying 6-BA after waterlogging can increase the ear length and row grains, decrease the bald length and bald ratio, but the ear coarse and ear rows was not have significant difference. 2. Effects of 6-BA on grain-filling characte ristics and endosperm cell proliferation ofsumme r maize after waterloggingWaterlogging affect grain- filling characteristics of summer maize significantly. Spraying 6-BA can improve the active grain filling stage(P) of summer maize; however, the days and growth of the biggest grain filling rate(Tmax and Wmax), the biggest grain filling rate(Gmax) and the average grain filling rate(Gave) showed no significant difference. The active grain filling stage(P) of maize hybrid DH605 in treatments of V3-6 and V6-6 were 12.38% and 7.11% lower than those of the control(CK), respectively; ZD958 were lower by 12.52% and 2.88%, respectively. The active grain filling stage(P) of maize hybrid DH605 in treatments of V3-6-T and V6-6-T were 8.02% and 3.07% higher than V3-6 and V6-6; ZD958 were higher by 12.52% and 2.88%, respectively.The number of grain endosperm cells decreased after waterlogging, spraying 6-BA can help relieve the decline significantly. In addition, spraying 6-BA after waterlogging can help reduce the decline of maxinum growth rate and growth when maxinum growth rate, effectively shorten the days to reach the biggest growth rate. 3. Effects of 6-BA on dry accumulation and nuteient uptake of summe r maize afterwaterloggingN, P and K were reduced significantly after waterlogging; however spraying 6-BA can effectively alleviate the inhibiting effect of waterlogging. N, P and K accumulation of maize hybrid DH605 in treatments of V3-6-T and V6-6-T were 17.23%、10.57%、25.00% and 40.75%、15.13%、14.81% higher than V3-6 and V6-6, respectively; ZD958 were 10.25%、20.66%、11.73% and 32.85%、19.17%、25.45% higher than V3-6 and V6-6, respectively. The dry matter accumulation decreased significantly after waterlogging; spraying 6-BA can help relieve the decline effectively. In the mature period, the dry matter accumulation of maize hybrid DH605 in treatment of V3-6-T and V6-6-T were 10.82% and 12.71% higher than V3-6 and V6-6, respectively; dry matter accumulation of ZD958 were higher by 5.22% and 8.93%, respectively. In addition, the amounts of nutrient accumulation in each organ and nutrient allocation proportions of grain were decreased significantly than CK, spraying 6-BA can help relieve the phenomenon effectively. 4. Effects of 6-BA on photosynthetic characteristics of summer maize afterwaterloggingLeaf area index(LAI), chlorophyll content and net phtotsynthetic rate(Pn) decreased significantly after watrelogging; however spraying 6-BA can effectively alleviate the inhibiting effect of waterlogging. In the flowering period, the net phtotsynthetic rate(Pn) of maize hybrid DH605 in Treatments of V3-6-T and V6-6-T were 9.57% and 8.38% higher than V3-6 and V6-6, respectively. ZD958 were higher by 2.96% and 4.05%, respectively. 5. Effects of 6-BA on leaf senescence characte ristics of summer maizeResults showed that superoxide dismutase(SOD), catalase(CAT) and peroxidase(POD) activity and soluble protein content decreased significantly after waterlogging. Whereas the content of malondialdehyde(MDA) increased significantly.Spraying 6-BA can help relieve the senescent process of summer maize after waterlogging. Superoxide dismutase(SOD), catalase(CAT) and peroxidase(POD) activity and soluble protein content increased significantly after spraying 6-BA; meanwhile, the content of malondialdehyde(MDA) decreased significantly, MDA content of DH605 and ZD958 in treatments of V6-6-T decreased by 12.24% and 14.08% on average, respectively. |
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