| Banana production has an important position in the tropical fruit industry of China;it plays an important role in the economic growth of tropical area and raises the level of farmers'living standard.However,in recent years,banana Fusarium wilt diseases are rampant,gradually transferred to the tropical north,inevitably suffer from natural disasters,such as:drought,waterlogging,and high temperature,making banana farmers suffered from heavy losses,while causing serious obstacles to the development of the banana industry.This paper mimicked the nature disasters within laboratory,mainly focus on drought,waterlogging and high-salt stress,trying to link the banana-growing phenomenon to the nature stress via simulated field tests.The collection of symptoms of under-stress banana,showed the growth differences of agronomic traits.We measured the biomass,stress index and the nutrient acquisition characteristics during stress treatments.Meanwhile,we also tested some internal physiological traits like the indexes of root activity and chlorophyll content.From all these evidences mention above,we could draw conclusions of banana stress respond through inner physiological indicators and biochemical mechanism.The main results and conclusions are as follows:1.The main symptoms of drought stress were the wilting of the top leaves,and aggravated with the increase of the stress,the top of leaf was superimposed on the back,the edge was yellow,and the bottom leaves withered and died,mild,moderate,severe period corresponding to drought stress level rank 1,2,3.The main symptoms of flooding stress were the small new leaf,the growth was blocked,the bottom leaves died.The main symptoms of salt stress are leaf coke dry,like burning,there are spots,and with the increase in fertilizer and salt symptoms increased.2?Drought,waterlogging and salt sterss could significantly inhibit the growth of bananas height,steem diameter,leaf area,leaves number,green leaves number.Compared with the matrix normal treatment,drought treatment were decreased by 13.58 cm,15.51mm,373 81 cm~2,2.83 leaves,6.65 leaves;compared with the normal soil treatment,soil drought treatment were decreased by 5.23 cm,74.58 cm~2,9.19 mm,1.50 leaves,4.5 leaves;compared with normal treatment,the waterlogging treatment respectively by5.29 cm,7.01mm,287.89 cm~2,1 leaf,4.5leaves;Under salt stress,with the increase of fertilizer application,the inhibition degree of agronomic traits was increased.compared with the normal treatment,hight salt treatment were decreased by 10.17cm,9.62cm,271.46 cm2,1.50 leaves,2.17 leaves.3.The response of banana adversity can be expressed by the stress stress index.In the severe period,the PHSI of the matrix drought and soil drought treatment decreased by 34percentage points and the DMSI decreased by a decrease of 81 percentage points and up to52 percentage points,respectively.In waterlogging stress,the PHSI and DMSI decreased27 percentage points and 45 percentage points respectively.The dry leaf stress index also increased with the increase of stress degree,and the drought stress of each symptom was significantly different.SSI and STI showed a downward trend,in severe period decreased by 39 percentage points.4?The total nitrogen content of the plants under the matrix drought stress reduced the total nitrogen content,but the total nitrogen content increased in the soil drought treatment plants.Matrix drought and soil drought decreased the total potassium content of rhizome in moderate and mild stage,respectively.The total potassium content in plant leaves was increased by 27.47%and 39.45%in the severe period.In the mild period,the total nitrogen content of banana root and leaf decreased by 14.29%,33.33%,and 29.17%,respectively.In the severe period,the total potassium content of banana stems and leaves increased by48.02%and 85.62%5?Drought,waterlogging and salt stress could reduce the root activity and chlorophyll content of banana,and decrease with the increase of stress degree.In the severe period,the root activity of substrate and soil drought stress decreased by about 70%,while that of soil drought and soil drought treatment decreased by 38%and 54%,which indicated that soil moisture had higher chlorophyll content 36%and chlorophyll content decreased by 45%.The root vigor of low,medium and high salt stress decreased by 55.78%,54.64%and83.94%respectively,and the chlorophyll content decreased by 34.46%,47.19%and43.24%respectively.Under drought stress,waterlogging stress and salt stress,the chlorophyll content had a good correlation with SPAD value. |
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