| Micronutrients such as transition metal for iron(Fe), manganese(Mn), copper(Cu), zinc(Zn) and metalloid for boron(B), chlorine(Cl) are one of essential elements for optimal plant growth and development. However, it has constantly happened that they are insufficient or deficient around the world. The growth and development of potato(Solanum tuberosum L.) are influenced by various environmental factors in which the homeostasis of mineral nutrition is crucial for the growth, starch accumulation, and tuberization in potato plant. Therefore, it is of fundamental importance that investigated carbohydrate accumulation and root morphology and shed light on the plant development and characteristic of carbohydrate distribution under different levels of micronutrient homeostasis. The test-tube seedlings of potato cultivars "Atlantic" were adopted in the experiment. Combined physiological and biochemical methods with inductively coupled plasma optical emission spectroscopy(ICP-OES), high performance liquid chromatography(HPLC) and root system scanner, the effect of different levels of micronutrient homeostasis on carbohydrate changes and root morphology was investigated. The results of this research as follows:Chlorophyll content decreased significantly under the micronutrient deficiency other than Cl treatment(increased markedly by 46%) and there was a maximum decrease in Fe treatment case, and suggested that the biosynthesis of chlorophyll was suppressed so that photosynthetic efficiency declined. Due to the reduction in chlorophyll content, carbohydrates were changed. The content of glucose and fructose was accumucated in seedlings upon Fe, Mn, B and Cl deficiencies, but fructose content only was accumucated in roots under Mn and B treatments. Sucrose content increased significantly in roots at Fe and Cl deficiencies while accumucated notly in shoots at Zn, Cu and B deficiencies. Starch content in both shoots and roots enchanced significantly(for Fe, Zn and Cl stress) and by up to 13 times under Fe deficiency. The content of soluble sugar in seedlings was higher than the control under Fe and Mn starvation and merely accumucated in shoots under Cu and B deficiencies. Above results showed that the degradation of polysaccharide and elevation of monosaccharide and soluble sugar were an important adaptive strategy for plants under Fe, Zn and Cl deficiencies, it also was discovered that the constraint of starch degradation in the aerial portion and transportion towards the underground portion brought about starch accumucation in Fe, Zn and Cl deprivation and which was responsible for the difference of plant morphogenesis under nutrient deficiency. In addition, morphological analysis of root system revealed that, total root length reduced significantly under Mn, Zn, Cu and Cl deficiencies, however increased notably under mild Fe and B deficiencies. In this respect, it was relevant to complete efficiently the degradation of carbohydrates and transport to root system for facilitating the absorption of microelements and ensured the growth and development of root system.Elemental analysis indicated that the content of Mn, Zn and Al increased significantly under Fe deficiency. The content of Mo and Zn enhanced significantly under Mn deficiency. The content of Cu and Al added under B deficiency, and Cu deficiency added significantly Fe content. At least in part, the increase of these elements possessed same family or similar atomic radius would relieve the shortage of micronutrient in seedlings. There would be another possibility to have common transport mechanism for Fe, Mn and Cu on the cell membrane. A sort of novel adaptive mechanism was found that selective absorption to certain element of compensative function could mitigate the damage resulting from micronutrient deficiencies. Additionly, it needs to continue to work hard to explain the mechanism that Zn deficiency led to decrease S content and Cl deficiency hindered K absorption. |
PDF Full Text Request