Effect Of Iron Deficiency And Boron Deficiency On Physiological Characteristics Of Two Kinds Of Poplar

Only a small proportion of iron can be absorbed by plant, though the abundance of iron in the crust, because of the influence of pH and oxidation The area and number of poplar iron-deficiency chlorosis is increasing year by year in the world-wide. Boron is an essential mineral nutrients and the boron deficiency is very common among trace elements in the plants. In the south area of China, soil boron deficiency in poplar plantation is a common phenomenon, which has great negative effects on the normal growth and wood properties of poplar.In this experiment, two cultivars of Poplar HuashiNO.1and I-72(Populusxeuramericana ’San Martino’) annual hardwood cuttings were selected as experimental materials. The materials were hydroponic cultured with boron deficiency and iron deficiency stress. Content of antioxidase activity, photosynthetic pigment content and osmotic adjustment substances after were determined of different stress treatments materials. The results are as follows:(1) Effects of iron deficiency and boron deficiency on poplar morphological index.Compared with the control treatment, iron and boron deficiency stress significantly reduced plant height of two poplar varieties. The longer the stress time, the more obvious the inhibitory effects on the seedling height growth is. The iron and boron deficiency have great effect on I-72seedling height than on Huashi NO.1. Compared with iron deficiency, the boron deficiency has great effects on plant root biomass, root/shoot ratio. Under the boron deficient condition, the biomass of root, stem and leaf decreased significantly.(2) Effects of iron deficiency and boron deficiency on photosynthetic characters of poplar.Under the iron and boron deficiency treatments, the total content of chlorophyll a, chlorophyll b and carotenoid were decreased in these two kinds of poplar. And the effect of iron deficiency on chlorophyll content is much great than boron deficiency. Leaf net photosynthetic rate and stomatal conductance were significantly decreased, while the intercellular CO2concentration were higher than that of control.(3) Effects of iron deficiency and boron deficiency on osmotic adjustment substance of poplar.Soluble protein increase significantly in iron deficiency treatment of two cultivar poplar, while the soluble protein decreases under the condition of boron deficiency. Under iron and boron deficiency treatments, the proline contents in leaf and root were increased of two kinds of poplar. The changes in roots were most obviously.(4) Effects of iron deficiency and boron deficiency on the antioxidant system of poplar.Under iron and boron deficiency treatments, the content of MDA in poplar’s roots and leaves increased significantly. Under iron deficiency, the SOD and POD contents in roots and leaves were increased firstly and then decreased. That maybe relate to the iron protein. Under boron deficiency, the SOD and POD become more activity in leaves and roots of poplar. But with the extension of stess time, the rising rate of decrease is less obviously compared with control. This may be related to the difference of different plant stress tolerance.