| Kuerle pear is one of the unique products in Xinjiang, which now has become the pillar industry ofBazhou. But in Kuerle pear cultivation, iron deficiency chlorosis affects the yield and quality of kuerle pearseriously. The purpose of this study was to research physiological response of pear rootstocks under irondeficiency and to determine Fe3+reeducate activity in the rhizosphere and total iron content in differentorgans through solution-culture technique. We used three kinds of pear seedlings as the experimentalmaterials and set two different iron supply treatments. And then we observed etiolation in pear rootstockseedling leaves. Combining the growth condition of Pyrus xerophila, Pyrus betulifolia Bunge and Pyrusxinjiang in calcareous soils, a series of physiological and biochemical indexes under different iron supplytreatments were analyzed and the iron deficiency pear rootstocks were screened. The results were shown asfollows:1. Iron played an important role in the process of chlorophyll formation. The lack of iron did harm to plantchlorophyll synthesis. The main effect of iron deficiency was the loss of chlorophyll in the new leaves.2. The iron uptake efficiency of pear rootstock seedling root system was inhibited, the mobility of the ironin plants was reduced, the effectiveness of iron in plants was weaken and the chlorophyll content of leavesdecreased in high pH surroundings.3. Iron deficiency could lead to increase in plant organic acid secretion and decrease in rhizosphere pH. Itmade Fe3+in the rhizosphere reduct to Fe2+which was able to be absorbed by the roots.4. The Fe3+reeducates activity of rootstock with resistance to iron deficiency was the highest, and the Fe3+reeducates activity of rootstock without resistance to iron deficiency was the lowest, namely Pyrusbetulifolia Bunge>Pyrus xerophila>Pyrus xinjiang. Pyrus betulifolia Bunge was able to use iron in theenvironment effectively for plant absorption.5. For the three kinds of pear rootstock seedlings with different treatments, the total iron content in the stemwas less than that in the leaves and roots. Once iron deficiency occurred, total iron content in the root wasfirst influenced.6. In Southern Xinjiang, the average pH value of the pear yard soil was about8.50, belonging to typicalalkaline soil. The average salt content was0.21g/Kg, belonging to light salinized soil.7. Pyrus xinjiang had a poorer adaptability in calcareous soils, and phenomenon of leaf etiolating wasserious. The total iron content in the leaves decreased fastest. Pyrus betulifolia Bunge had the lowest leaveyellowing degree and total iron content in the leaves fell by only2.33mg/K·DW, which was consistentwith results of the solution-culture experiments.8. In the dry calcareous soils in Southern Xinjiang, Pyrus betulifolia Bunge showed a high adaptability, andshowed an absolute advantage in the investigation of the growth index. |
