Study On Stress Of Bolboschoenus Planiculmis On The Growth And Development Of Mechanical Harvest Cotton

Bolboschoenus planiculmis Egorova is a malignant weed with a well-developed base,fast growth rate,high population density,strong reproductive ability and adaptability.With the change of cotton cultivation model in Xinjiang,B.planiculmis has become one of the main harmful weeds in cotton fields.In this study,cotton was used as the research object.The effects of the population density of B.planiculmis the absorption and accumulation of cotton nutrients,the effects of the population density of B.planiculmis on the agronomic and economic traits of cotton,and the continuous damage of B.planiculmis on the agronomic and economic traits of cotton,and the effects of B.planiculmis Rhizospheric exudates on cotton.Clarify the harmful mechanism of Bolboschoenus planiculmis on cotton,and provide a theoretical basis for the establishment of scientific and reasonable measures for controlling B.planiculmis.The main results of the study are as follows:1.Effects of rhizosphere secretions of B.planiculmis on cotton The experimental results showed that the rhizosphere secretion on B.planiculmis had significant effects on the cytokinin and auxin content in cotton leaves,and decreased with the increase of the irrigation times of the rhizospheres of B.planiculmis.The cytokinin content of cotton leaves under the5-30 treatment was the lowest at 2.03?g/g.The auxin content of the cotton leaves at the 7-30treatment was the lowest at 0.92?g/g.The high root rhizosphere secretion concentration of B.planiculmis could significantly inhibit the growth of the underground part of cotton.The main root length,lateral root length,and root fresh weight all decreased with the increase of irrigation time.The cotton had the smallest main root length,lateral root length and root fresh weight under 7-30 treatment,which were 6.33cm,5.17cm and 0.63g.It is indicated that the high level of rhizosphere secretion of B.planiculmis can reduce the content of cytokinin and auxin in cotton leaves.The effect of the rhizosphere secretion of B.planiculmis on the growth of cotton is not significant,but it can significantly inhibit the growth of cotton underground.2.The results of experiments on the absorption and accumulation of cotton nutrient density by the population density of B.planiculmis showed that:At the cotton seedling stage,when the population density of B.laniculmis was 20 plants/m~2,the soluble protein content of cotton leaves increased by 1.5336 mg/g compared with the CK,and there was no significant difference in other indicators.However,the population density of B.planiculmis was high,which reduced the soluble protein content of cotton leaves and increased the soluble sugar content of cotton leaves.At the cotton bud stage,when the population density of B.planiculmis was less than 40 plants/m~2,it could significantly increase the phosphorus content in cotton leaves,but had no significant effect on other indicators.In the cotton boll stage,the population density of all B.planiculmis populations could reduce the content of potassium and soluble sugar in cotton leaves.When the population density of B.planiculmis was 20 plants/m~2,it had no significant effects on cotton yield,and cotton yield was significantly reduced under other population densities.It is shown that when the population density of B.planiculmis is higher than20 plants/m~2,it had significant effects on the absorption and accumulation of cotton nutrients and cotton yield.3.The results of experiments on the effects of population density of B.planiculmis on the morphological index,yield and quality of cotton show that:Cotton plant height,stem thickness and main stem node number decreased with the increase of the population density of B.planiculmis,which has the greatest impact on the upper boll number and single boll weight of cotton.When the population density of B.planiculmis is 80 plants/m~2,it has the greatest effect on the boll number and single boll weight of cotton,compared with the control,it was reduced by 2.86 and 1.82 g,respectively..The yield of cotton decreased with the increase of the population density of B.planiculmis.The population density of B.planiculmis was 20 plants/m~2,which had little effect.The effect on cotton fiber quality is mainly reflected in the effect on cotton fiber micronaire value and maturity.The results indicated that the population density of B.planiculmis can greatly affect cotton plant height,stem thickness,and number of main stem nodes,which in turn greatly affects cotton yield.When the population density of B.planiculmis has a small impact on cotton yield and quality,the population density of B.planiculmis should be controlled below 20 plants/m~2.4.The effects of continuous damage of B.planiculmis on cotton agronomic and economic traits.The experimental results show that he plant height and stem thickness of cotton decreased with the duration of the damage of B.planiculmis.When the continuous damage period of B.planiculmis was less than 30 days,there had been no significant effect on the number of main stem nodes and fruit branches of cotton,but significantly less than 30d.The continuous damage period of B.planiculmis had no significant effects on the number of bolls in the middle and lower fruit branches of cotton,but significantly reduced the number of bolls and the weight of single bolls on the upper fruit branches.The continuous damage period of B.planiculmis is more than 10 days,which can significantly reduce the cotton yield and cause the cotton fiber quality index to decrease.This shows that the continuous damage period of B.planiculmis is greater than 10 days,which can significantly reduce the cotton yield and cause the cotton fiber quality index to decrease.According to the cotton yield index of this experiment,the control of B.planiculmis should be no later than 30 days before cotton topping.