The Effect Of GA₄₊₇ And 6-BA Priming Seedlings Treatment On The Growing Development And Senescence Resistance In Late Growth Stage Of Maize

Plant hormones regulate plant growth,development and differentiation in various stages of plant growth,respectively.Studying the effect of exogenous hormones on the growth and development of maize and the anti-aging indexes in the later stage is beneficial to maize yield.Therefore,the seeds of maize（zhengdan 958）was taken as experiment materials and treated with gibberellin and cytokinin.The research which conducted by plot experiment measured plant height,stem diameter,leaf area per plant,root morphology,root-shoot ratio and photosynthetic characteristics,studied the effect of GA₄₊₇ and 6-BA priming seed on the maize seedling growth condition.The study conducted by field experiment measured the photosynthetic characteristics,protective enzyme activity and the change of dry matter accumulation of maize in different stage,discussed the effect of GA₄₊₇ and 6-BA priming seed on photosynthetic characteristics and yield of corn seeds.The results were as follow:1.The suitable concentration of GA₄₊₇ and 6-BA priming seed can enhance leaf area per plant,root length,root surface area and root volume of maize seedling,obviously increase the dry matter weight.The result showed that GA₄₊₇ exhibited inhibition effects to certain extent in terms of stem diameter and root-shoot ratio,6-BA had no obvious effects on plant height and root cap ratio.On the whole,the most evident effects were with 60 mg/L GA₄₊₇ and 10 mg/L 6-BA in the present experiments,which significantly improved photosynthesis and fluorescence parameters,had a good regulation function on maize seedlings,and promoted seedling growth.2.60 mg/L GA₄₊₇ could significantly promote the accumulation of dry matter in maize,and the impact on the early growth stage was greater than the late.10 mg/L 6-BA priming the seed not only promoted the accumulation of dry matter in maize earlys stage,but also light energy utilization during the grain filling stage,thereby accumulated more dry matter.60 mg/L GA₄₊₇ and 10 mg/L 6-BA priming seed significantly promoted the dry matter accumulation of maize organs in mature stage,the total dry matter weight of summer maize in 2015 increased by 9.3% and 9.2% respectively compared with the control,14.3% and 11.5% of spring maize in 2016.While significantly increasing the proportion of dry matter in the spike,thus increasing the harvest index of maize.And can significantly increase the distribution of dry matter in the female spike,thereby increasing the harvest index of corn.3.60 mg/L GA₄₊₇ and 10 mg/L 6-BA priming seed could maintain a higher activity of SOD,POD and CAT,reduced MDA content in the critical growth period of corn silking and filling stage of maize,thus delaying the senescence,and made ear leaf keep more photosynthetic pigment content at medium-late stage,extended photosynthesis time of corn growth stage,and significantly improved the leaf area index in silking stage,increased by 33.5% and 24.2% than control group in 2015 of summer maize,13.6% and 5.9% in 2016 of spring maize.4.60 mg/L GA₄₊₇ and 10 mg/L 6-BA priming seed obviously increased the net photosynthetic rate in corn key growth period.In the filling period,which increased by 33.4% and 33.8% in 2015,14.0% and 18.5% in 2016,respectively,and promoted stomatal opening,increased the intercellular CO2 concentration and enhanced the water use efficiency.The teratments priming with 60 mg/L GA₄₊₇ and 10 mg/L 6-BA also can improve the chlorophyll fluorescence parameters in filling period: significantly improved PS Ⅱelectron transport rate（ETR）and actual quantum efficiency（Yield）,effectively increased the photochemical quenching coefficient（qP）and reduced the non-photochemical quenching coefficient（qN）,thus improved the light conversion efficiency and promoted photosynthesis of corn.5.The suitable concentration of GA₄₊₇ and 6-BA priming seed can enhance maize yield.When GA₄₊₇ concentration is 60 mg/L,the maize yield reached 12626Kg/hm2 and 16997Kg/hm2 in 2015 and 2016,respectively,compared with the control were significantly increased by 12.7% and 23.1%.When 6-BA concentration is 10 mg/L,the maize yield reached 14219Kg/hm2 and 14632Kg/hm2 in 2015 and 2016,respectively,compared with the control were significantly increased by 17.3% and 21.2%.