| The potted one-year old seedlings of Carya illinoensis were used to study the effect of salt and water stress on growth, photosynthetic characteristics, and some indexes associated with anti-adversity. The results are as follows,There was no significant effect of0.1%NaCl concentration on the growth and photosynthesis of Carya illinoensis seedlings, compared with the control group, growth and net photosynthetic rate increased. While the growth and photosynthesis were significantly decreased when the NaCl concentration was over0.2%, and the higher the NaCl concentration was, the lower the growth and photosynthesis showed. The growth of pecan seedlings almost ceased and the photosynthesis became quite weak under the treatment of NaCl concentration over0.7%. And the survival rate dropped to22.2%, even lower. This indicated that pecan is not suitable for cultivation in the high-salt region. In addition, the stomatal limitation might be the main factor restricted the photosynthesis under the treatment of lower NaCl concentration(≤0.4%), while the higher NaCl concentration (>0.4%)affected the photosynthesis usually by non-stomatal limitation factor.The drought stress showed the most significant on Carya illinoensis during the water single factor test. Photosynthetic rate and some indexes decreased when treated by6-day drought, pecan plants began to death when10-day treatment, and all plants died when23days. All the plants were survived and grew well under indirect water treatment during the test. Compared with control group, the growth, photosynthesis and physiological indexes showed insignificant, this indicated that the pecan can adapt to short-term flooding. The plants survival rate was87.5%under continuous waterlogging stress. The Pn value dropped sharply when treated20days later, and appeared some adaptive traits such as the increase of lenticel, these indicate that the pecan can tolerate to flooding in some extent. |
PDF Full Text Request