Study On The Relationship Between Morphological As Well As Physiological Indexes And Drought Resistance Of Seabuckthorn

In this paper four varieties of seabuckthorn were used including Hippophae rhamnoides ssp. sinensis, Hippophae rhamnoides and two hybrids of them, and systematic comparison study was done on their surface structure, anatomical structure, protective enzymes, osmotic adjustment matter, MDA, membrane relative permeability, etc. And also their acclimation to drought stress was analyzed, with the purpose of providing theoretical basis for the plantation and management of young trees of seabuckthorn. The results are listed below.1. On the leaves of Hippophae, there are highly dense epidermal hairs, which can affect microclimate to reduce water loss and high-photo-flux-density injury in the case of drought. The thick periostracum is also an effective way to reduce cell dehydration. Hippophae rhamnoides ssp. sinensis has smaller leaves, more layers of epidermal hair and denser stomas than H. rhamnoides.2. The leaves have relatively thicker palisade tissue, so Hippophae has anatomical structure that is the characteristics to adapt to drought stress. Under drought stress, the thickness of leaves decreases, and the development of the palisade is better than spongy tissue's, which is a strategy to deal with drought stress. The ratio of palisade tissue to spongy tissue of H. ramnoides ssp. sinensis is higher than those of H. rhamnoides and the two hybrids. So H. rhamnoides ssp. sinensis is nore adaptive to drought stress.3. Suffering from drought stress in field, Hippophae accumulates more proline and soluble saccharide in the leaves, and with the stess time or stress degree going on, their ability to accumulate proline is: H. rhamnoides ssp. sinensis > H. rhamnoides; while their ability to accumulate soluble saccharide is: H. rhamnoides > H. rhamnoides ssp. sinensis. The variation of the contents of proline and soluble saccharide in the leaves of Hippophae increase as the degree of drought stress increases. Taking all the results into accout, proline contributes more to osmoregulation than soluble sacharide does.4. Under different drought stresses in field, the activities of SOD and POD in leaves of Hippophae increase in the beginning stage of drought stress, then decrease with the prolonging of the drought stress. SOD activity is: H. rhamnoides > H. rhamnoides ssp. sinensis, while POD activity is opposite. With the increase of drought stress and prolonging of the stress time, MDA content in the leaves increases continuously, and the content is H. rhamnoides > H. rhamnoides ssp. sinensis. As to membrain relative...