Nutrients Diagnosis Of Banana With B,Fe,Mn,Zn And Cu Deficiency And Banana NPK Nutrition State Under The Micro-nutrients Deficiency

The banana has been planted in tropical and subtropical regions with high temperature and heavy rainfall condition which causes nutrients losses easily.The fertilization during the banana growth depended mainly on farmers experience.Thus,excess of fertilizers with irrational NPK ratio have been applied to increase banana yield as a routing measure in the banana cultivation.The over use and abuse of fertilizers have resulted imbalance nutrition,nutrients leaching,runoff and series of environmental issues.Therefore,banana nutrition has always been one of the major factors to restrict development of banana production and industry.However,in addition to the scientific methods such as soil testing and formulated fertilization,there is still lack of banana nutrients diagnosis that can help banana farmer to recognize what kind of nutrients restricts banana growth.In addition,in terms of banana nutrition theory,it is not yet clear what the effects of nutrient stress on nutrient content,accumulation,distribution,and nutrient balance in various organs of bananas.The research room has already done detailed research on the balance of large and medium-sized elements in bananas and has established the nutritional diagnostic maps.Based on the above research results,this article focuses on the nutritional diagnosis and nutritional balance of trace elements in bananas.In this paper,hydroponic method was used to study the response to the deficiency of nutrients in different growth stages o f banana under the stress of single trace element,and the typical symptoms of lacking nutrients were taken and collected.The effect of nutritional deficiency on nutrient accumulation and distribution in banana was analyzed by collecting samples.The results of nutritional diagnosis of large and medium-sized elements provided a theoretical basis for the establishment of a complete nutritional diagnosis map of bananas and the recommendation of scientific fertilization.The main results are as follows:(1)The symptoms of boron,iron,manganese,zinc,and copper deficiency were evident in bananas on 5,6,15,52 and 76 days after nutrient-deficient treatments.The consistent phenomenon was that the leaves first showed symptoms of nutrient deficiency.(2)Boron,iron,manganese,zinc,and copper deficiency all caused chlorosis in banana leaves,but also having their own characteristics.At the beginning of boron deficiency,the chlorotic stripes appeared perpendicular to the lateral veins of the young leaves.As the boron deficiency was intensified and last,the chlorosis stripes became woody and necrotic,then the entire leaf lost its green color and the leaf margin nicks.With the deformity of the leaves,only the main veins of the newly pumped leaves were left.Finally the growing points were necrosis and the new leaves were difficult to pump.When the symptoms of iron deficiency occur,the color of newly-drawn leaves gradually changed from light green to light yellow and yellow and turned into yellow-white and white when severe.Finally the newly-pumped leaf withered wholly or partly.Chlorosis was firstly observed in the margin of the young leaves in manganese deficiency,then the entire newly pulled leaf appeared chlorosis and brown strips of different densities crossing the main veins to the margin of the new leaf were observed in the new leaves.The young leaves became thinning and brittle.There were uneven sized mottles appeared on the top leaves,finally the newly-pumped leaf withered wholly or partly In zinc deficiency,the leaf area of newly pumped leaves became smaller and the whole leaf turned brown and withered,accompanied by a pronounced strip-like loss of green and the middle and lower parts of the leaves were pale red.Copper deficiency resulted in yellowing of the margin of the leaves,the bigger angle between the newly-pulled leaf and pseudostem and almost a straight angle between two young leaves.(3)The boron,iron,manganese and zinc deficiencies decreased chlorophyll content of leaves significantly.During the period of severe boron,iron,and manganese deficient stress,the chlorophyll content of banana leaves was 40%,0.1%,and 17.1% of that of the normal leaves,respectively..During moderate zinc-deficient stress period,the chlorophyll content of banana leaves was 33.5% of that of normal leaves.(4)The boron,iron,manganese,zinc,and copper deficiencies all significantly increased the content of malondialdehyde in banana leaves.During the severe boron,iron,manganese,zinc,and copper deficient stress,the malondialdehyde content was 3.2,1.7,and 2.8 times more than that of normal leaves.During,the MDA content of bananas leaves in the mid and moderate zinc-deficient stress periods was both 1.8 times more than that of normal.(5)The boron,iron,manganese,zinc,and copper deficiencies caused a significant decrease in banana root activity..Compared with the normal treatment,the banana root activity in the severe boron,iron and manganese deficient stress decreased by 81.3%,59.1%,and 64.1% respectively;the banana root activity in the moderate zinc-deficient stress decreased by 71.4%;the banana root activity in the mild copper-deficient stress decreased by 51.2%.(6)Boron-deficient stress significantly reduced the accumulation of N,P and K in the whole banana plant.The cumulative N,P,K accumulation of whole banana plant under normal treatment was 2.9,3.7 and 2.3 times more than that of banana in severe boron-deficient stress treatment.Iron-deficient stress reduced the accumulation of N,P and K in the whole banana plant significantly.The cumulative N,P,K accumulation of normal banana was 3.5,4.7 and 3.2 times as large as that of severe iron-deficient stress treatment.Manganese-deficient stress significantly reduced the accumulation of N,P and K in the whole banana plant.The cumulative N,P,K accumulation of whole banana plant under normal treatment was 2.3,2.5 and 3.6 times more than that of banana in severe Manganese-deficient stress treatment.Zinc-deficient treatment significantly reduced the total nitrogen accumulation of the whole plant,while had no significant effect on the total phosphorus and potassium accumulation.The cumulative N accumulation of whole banana plant under normal treatment was 1.3 times more than that of banana in moderate zinc-deficient stress treatment.There was no significant difference among the cumulative N,P,K of whole banana plant between the normal treatment and copper-deficient treatment.(7)Boron,iron,manganese,zinc,and copper deficiencies,all significantly affected the distribution ratio of N,P and K at different leaf positions of bananas.The consistent pattern was that the lack of nutrients caused a decrease in the proportion of N,P and K accumulated in newly-extracted leaves with the differences in the degree of decline and the beginning of a decline in leaf position.