Research On The Appraisal Of Stylosanthes Guianensis Quality,Al-tolerance Character And The Physiological Mechanisms Of Al-tolerance Diversity

Aluminum toxicity and nutrient deficiency were main factors restricting crops growth in the acid soil. Stylosanthes is an excellent tropical leguminous pasture with high nutritional value and ideal garden conservation and green manure crops with well adapted ability in drought, infertility and aluminum tolerance. Stylosanthes guianensis Sw. has the most abundant genetic resources and largest cultivated area. Whereas, a comprehensive analysis of nutritional value, manure value and aluminum resistance of the S. guianensis Sw.has not been done. This study systematically evaluated the nutritional value, manure value and aluminum tolerance under different Al concentration of the134germplasms of S. guianensis Sw.. The nutrition quality and Al tolerant capacity of S. guianensis Sw. were analyzed and classified, and then four germplasms which were different in Al tolerant capacity were selected to research the Al tolerant mechanism, The major results as follows:134germplasms were high in nutritional value and the average of crude protein content was117.lg·kg-1. And2germplasms nutritional value were higher significantly than var96,9germplasms nutritional value were lower significantly than var96, the other germplasms were not significantly. Besides, this species had high manurer value, among which98.5%were belonged to second-order organic manure.Al-tolerance of S. guianensis Sw.germplasms were screened. They were different in root elongation and hematoxylin-stained index number of S. guianensis after exposed to0,10,30,50,70μmol. L-1Al solution for24h, and separately divided into3groups which were Al-tolerant type, Al-ordinary type and Al-sensitive type. The classification results divided by two different indicators was almost consistent.Germplasms of4which were sample9(Al-sensitive), sample10(Al-tolerant), sample96(Al-ordinary) and sample107(Al-tolerant) were selected to research the Al tolerant mechanism by nutrition solution combined with the results above. The results showed that the accumulation of O2-and H2O2in S. guianensis Sw. leaves were promoted under Al stress, and the accumulation was sample9> sample96> sample107> sample10. The electrical permeation rate and malondialdehyde (MDA) content of S. guianensis Sw. leaves were increased Al stimulation, the increase range was sample9> sample96> sample107> sample10. The increase range of proline (Pro) content was sample9> sample96> sample10> sample107. Aluminium stress changed metabolic enzyme activity of the S. guianensis Sw. leaves, and the Al-sensitive genestype sample9kept higher SOD activity, while Al-tolerant genestype sample107and sample10kept higher POD activity and CAT activity. The Al3+content in the roots of Al-sensitive germplasms were higher than Al-tolerant germplasms under Al stress. Al had also inhibited th growth of overground part, underground part and the accumulation of dry matter, and influenced greater on Al-sensitive germplasms than Al-tolerant germplasms.