Studies On Biological Characteristics And Responses To Spatial Heterogeneity Of Water And Nutrients Of Rosa Rugosa Roots

With wild varieties and cultivars of Rosa rugosa as experimental material, this thesis studied the root annual growth pattern in pots and open field, correlation between root growth and ground parts, root physiological and biochemical metabolic pattern of rose roots;and it worked over the growth, root architecture and physiological characters affected by nutrient elements, soil compaction, soil texture and fertilizer application amount, and responses to heterogeneous nutrient and water of Rosa rugosa roots. The results were as followed:1. We survey the growth pattern of rose roots in wild varieties and cultivars of Rosa rugosa by the way of potting, root drill and modified root cellar and study the correlation between the roots growth and the top growth, root physiological and biochemical metabolic pattern of rose roots. The results showed that:(1)There are three growth peaks of rose new roots each year, and the peak period depends on the cultivating ways and ages of plants. The growth peaks of young plants in pots are on June, July and September, but that of the open filed are slightly later. The root growth peaks of perennial plants in open field are at the end of March, May and September. The roots quantity of potted rose is obviously higher than that in open field. There were almost no difference in the period of root growing peaks between the perennial plants of wild varieties and cultivars.(2)The growth of roots and the new shoot of Rosa rugosa grow in both helping each other and mutually contradictory, showing the growth of alternating phenomenon. To the new cultured plants, after the roots growing quickly there is the new shoots growth peak, but the shoots growing quickly restrain the new roots grow in return. The first growth peak of the perennial rose plants in open field is for accumulating nutrient substance to meet the need of branching, leaves growing and flowering. In return the shoot growing quickly will restrain the roots growing. There is the second root growing peak after flowering, the quantities of roots reduce with the fruits growing, and grow speedily after fruits mature, and appear the new root growth peak.(3)The content of sugar and starch in rose roots in the growing season, would be in downward tendency after forming an absorption peak in spring. And then it would accumulate more with the slowing growth in later period. The content of amino acid was increased with the rapid growth of the aerial parts of rose roots. Meanwhile, three time peaks would be formed in spring and summer and the content of amino acid was increasing rapidly with the temperature dropping in autumn. However, the content of protein is opposite. The activities of SOD and POD were almost the same, which became three times of active peaks in spring and summer, and would be in a rising tendency with the growth of the aerial parts, but the changes were not so much. The content of starch, amino acid and protein, as well as the SOD, POD activities in roots of wild roses in spring and summer were significantly higher than that of rose cultivars, but that in autumn were reversed. The content of sugar in wild roses has been higher than that of rose cultivars. The content of carbon and nitrogen substances in different periods and the activities of SOD and POD also affect the resistance and the dormancy time of wild roses and rose cultivars.2. The sand culture system was used to study the effect of N, P, K-deficiency on the parameters of root architecture and activity of Rosa rugosa young seedlings. The results showed that proportion of tiny root decreased. The density and diameter of root were increased significantly, and the branches angles enlarged, and the roots tended to horizontal distribution, root activity obviously declined 19.08%,29.96% and 55.59% than that of control respectively, and the root fractal dimension diminished significantly under N, P, K-deficiency condition. Under N, P-deficiency condition, the length and number of lateral root, the total length, surface area and volume of root increased significantly. Under K-deficiency condition, on the contrary, the above specifications decreased 8.70%,3.95%,47.75%,56.03% and 70.00% by comparison.The root activity and fractal dimension under K -deficiency condition was less than under N, P -deficiency.3. The experiment was conducted with potted seedlings of Rosa rugosa in order to study the effect of soil compaction with different SBD(1.10 g·, 1.30 g·cm^-3,1.50g·cm^-3)on the root architecture and nitrogen metabolism of the seedlings. The result showed that the values of growth index and biological yield under different SBD were 1.30g·cm^-3>1.50g·cm-3>1.10g·cm^-3.The ratio of R/S of plant was decreased with soil compaction increasing, and the R/S of the 1.50g·cm^-3 SBD was significantly lower than that of the 1.10g·cm^-3 and 1.30g·cm^-3 SBD.The root growth of the potted seedlings were inhibited as the soil compaction was increased, including root length, lateral root number and tap root diameter, but the average diameter and surface area of root was increased. The root activity, NO₃^—-N and NH₄+-N contents, NR activity in root were the largest in the 1.30g·cm^-3SBD, then the 1.50g·cm^-3 SBD and the 1.10g·cm^-3 was the lowest.GS activity in root was increased as the soil compaction increasing. The experiment indicated that the soil compaction was a crucial factor to affect nitrogen metabolism and influence the absorption and utilization of nutrients in plants. And 1.30g·cm^-3 SBD was favorable for plants to grow.4. A pot experiment was carried out to explore the characteristics of growth, root architecture and physiological characters of seedling of Rosa rugosa planted in sandy, loam and clay soil. The results showed that, the top growth quantity of in loam was the highest, the diameter of main root and average was the biggest, quantity of lateral root was the most, total length of root and surface area was the biggest; all these of them in sand were the lowest, and these of them in clay were the moderate, but the R/S of Rosa rugosa in clay was lower distinctly than in sand and loam. the root activity of Rosa rugosa in sand and loam were higher than that in clay, the root activity of Rosa rugosa in loam was the highest; the content of NH₄⁺-N and NO3--N of roots, NR activity in root was almost the same, all of them were the highest in loam and lowest in sand; GS activity in root was the largest in clay, then in loam and the lowest in sand.5. The seedlings of Rosa rugosa were used to study the effect of different fertilizer application amount on the growth, root architecture and activity under pot culture condition. The results showed that the plant height, term diameter, top fresh weight increased with the increasing fertilizer application amount, but above three indices decreased when the fertilizer application amount was higher(9g/pot);the R/S decreased with the increasing fertilizer application amount. The diameter of tap root, average diameter, number, total root length, root surface area and root activity increased with the increasing fertilizer application amount, reached the highest level supplied with 6g/pot.Rational fertilizer application amount was conducive to growth and development of Rosa rugosa.6. The medium culture was used to study the effect of heterogeneous nutrient and water on root architecture, root mass distribution, top mass, R/S, fine root diameter and SRL in greenhouse. The result showed that the root of Rosa rugosa was responded sensitively to water and nutrient heterogeneity, growth and distribution of root were affected obviously by space heterogeneity; growth quantity of up ground parts, total root and R/S treated in water and fertilizer heterogeneity were less than in homogeneity, and the R/S was reduced; roots grew quickly and total growth quantity was added clearly in fertilizer and irrigated area, and the growth were restrained in no nutrient and water area. Compared with the no fertilizer area, the diameter of fine root decreased and increased SRL were beneficial for absorbing and transporting of nutrient and water, in the no irrigation area, though diameter of fine root decreased, but the low SRL reduced the ability of absorbing water, reduced the total quantity of growth and then were bad to rose growing. Rose growing affected by water heterogeneity was more obviously than that by fertilizer heterogeneity.