Several Acid Stress On Different Chinese Fir Clones Of Chlorophyll Fluorescence Parameters

Allelopathy refers to the interference generated by the allelochemicals yield from the process of the growth or the decay of the plant to the others nearby. Chinese-fir is one of the most important fast-growing timber trees in South China, whose allelopathy has been confirmed by scholars in home and aboard. Continuous planting of Chinese-fir will cause soil degradation, and the productivity of Chinese-fir plantations will seriously influenced. Autotoxicity is a main reason of soil decline in continuous planting. Currently, gallic acid, salicylic acid and cinnamic acid and many other substances had been identified as the allelochemicals of Chinese-fir.Employing tissue culture as experiment method, the study was carried in optical self-supporting incubator to eliminate the interference of external and save time and space. O-hydroxy benzoic acid and cinnamic acid were added as stress factors in sand matrix without sugar to investigate the effect of the two phenolic acids to the chlorophyll fluorescence of seven selected clone seedlings of Chinese-fir. O-hydroxy benzoic acid (40 mg·L-1, 80 mg·L-1, 120 mg·L-1) and cinnamic acid (30 mg·L-1, 65 mg·L-1, 100 mg·L-1) were used to study the variation of chlorophyll fluorescence parameters in the seven selected clone seedlings. The study analyzed the variation of Fo, Fm, Fv, Fv / Fm, Fv / Fo,φPSⅡ, qP , qN and NPQ in different stress period (0-7 days early, medium 8-14 days, 15-21 days later) to provide scientific basis and theoretical reference for selecting allelochemicals resistant variety and establishing a evaluation system of allelochemicals resistant. The results show that: 1, Different acid stress on the fir clones of Fo, Fm and FvPSⅡreaction center to increase the heat dissipation caused Fo decreased, PSⅡreaction center damage or reversible inactivation of the increase caused by Fo. Therefore, the changes can speculate Fo situation and possible reaction center light protection. 21 teachers of Chinese fir clones on the run, in the o-hydroxy benzoic acid 40 mg·L-1 stress, stress 7 days, 14 days, 21 days after the Fo value than the control treatment, the Fo values decreased 3.5%, rising 10.56 percent, increased 3.1%. This shows that different clones in different concentrations of phenolic acids under the stress of the Fo value is first decreased and then increased, indicating prolonged with the stress of the clones gradually start recovery mechanism may be related to its own strong resistance.From the determination of the Fo, Fm, Fv data seen in different stress time, as the stress concentration, different values of Chinese fir clones Fo gradually increased, while Fm and Fv value was reduced after the increase. The fir clones in terms of division 103, in the 120 mg·L-1 salicylic acid stress, the stress 7 days, 14 days, 21 days after the Fo value than the control treatment, the Fo values increased by 1.68%, 9.42%, 6.97%, stress 7 days, 14 days, 21 days after the Fv value than the control treatment, the Fv values were reduced 16.06%, 9.13%, 9.75%. Stress at different times in different stress concentration, either increasing or Fv Fo down all of its resistance to enhance performance. Similarly, results obtained by the Chinese fir clones FS01, FS21, and its resistance to strong division 103.2, Different acid stress on Chinese fir clones of Fv / Fm and Fv / FoFluorescence parameters, Fv/Fm and Fv /Fo is recognized as an important basis for photosynthetic efficiency. Fv /Fm of plants sensitive indicator of photoinhibition occurred, but because of the light to protect PSII reaction of the non-photochemical energy dissipation and the PSⅡinjury can cause this ratio decreased. As shown, FS13, and 103 teachers were decreased, and with the increasing concentration of acid stress, Fv /Fm value is getting smaller and smaller, which indicates that the active site by the PSⅡinjury, and fall under the larger the greater the damage. Meanwhile, Thomas proved that Fv / Fm decline was due to decline and Fo Fm increased, and the decline was mainly caused by the Fm. Comparison of seven clones of Fv/Fm decrease of the process, Found that FS13 and a larger decrease in division 103, and the remaining five clones showed a weak upward trend. Note by the post-Salicylic Acid Stress, FS13, and division 103 of photosynthesis affected, but still show some acid, whereas the remaining five clones than the FS13 and lighter photoinhibition division 103, that acid stress was more strong.In this study, different acid stress on different clones of Chinese fir Fv/Fm and Fv/Fo values did not change significantly, the difference was not significant. Salicylic acid in stress, with increasing concentration of acid stress, the clones Fv/Fm and Fv/Fo values continue to decrease, the results indicate that salicylic acid 120 mg·L-1 stress, PSⅡphotochemical system fir leaves hurt reduce the original PSⅡphotochemical efficiency, so that the active site of Chinese fir seedlings PSⅡpotential damage to the original reaction of photosynthesis was inhibited. In the acid stress, with the increasing concentration of acid stress, the clones Fv/Fm and Fv/Fo values increased and then decreased, indicating that the first start recovery mechanism, and then lead to fluorescence quenching reduction, photosynthetic electron transport and membrane The energy state of gradually suppressed, leading to hurt PSⅡphotochemical system, PSⅡpotential damage to the active site. Research shows that Chinese fir clones FS07 and the FS21 has good resistance and better photosynthetic performance and selection For future high-growth, high photosynthetic rate of Chinese fir clones provides a theoretical basis.3, Different acid stress on the fir clones of qP and NPQqN and NPQ are changes in response to heat dissipation, but NPQ than qN more accurately reflect the clonal situation of non-photochemical quenching. QP and qN values generally between 0 and 1 change, NPQ greater than 1. From the measured data are available in different concentrations of acid stress, qP values of all clones and NPQ values were increased significantly. The fir clones FS01, the cinnamic acid in the 30 mg·L-1 stress, stress 7 days, 14 days, 21 days after the qP values than the control treatments qP values were increased by 20.41%, 24.49%, 40.82%, while stress 7 days, 14 days, 21 days after the NPQ values than the control treatments NPQ values increased by 40.63%, 43.75%, 46.88%. Can be seen that stress concentration at different time under the same stress NPQ values rise higher than the value of qP and NPQ values rise higher, the less the damage to photosynthetic apparatus, which has to a certain extent, improved its the ability to resist acid stress. NPQ values increased, indicating that the Calvin cycle activity by increasing the degree of inhibition, PSⅡpotential ability to enhance heat dissipation of clone FS01 is a kind of protection. The trial screened, clones with strong resistance FS01, FS07, FS21, and 103 divisions, while the less resistant clones have FS01 and FS13. Acid stress on the damage caused by fir clones with the stress time, and if coercion short time, after a certain time after the recoverability of its functions; But if the stress time is longer, there may be fir seedlings caused irreversible damage.However, the cinnamic acid 65 mg·L-1 stress clone FS13 and cinnamic acid 100 mg·L-1 normal stress of 103 clones of NPQ value fluctuated with the other treatments NPQ values of different trends, with the stress time increased NPQ first and then decreased. In acid 65 mg·L-1 stress, stress clone FS13 7 days, 14 days, 21 days after the NPQ value of NPQ values than the control treatment increased 27.91%, respectively, increased 40.7%, decreased 10.47%; in acid 100 mg·L-1stress, stress of 103 clones division 7 days, 14 days, 21 days after the NPQ values than the control treatment of NPQ values increased 4.35%, rising 6.52%, 10.87% lower. As the stress time, NPQ gradually increased, indicating that the Calvin cycle activity by increasing the degree of inhibition, PSⅡpotential ability to enhance heat dissipation of 103 clones FS13 and the division itself is a protective effect; as Training time to continue to extend, NPQ began to decline, indicating that clone FS13 and division of normal physiological functions 103 are subject to certain injuries, heat dissipation ability of the weaker. The results showed that acid stress on the damage caused by fir clones with the stress time, and if stress is shorter, after restore its function after a certain time; but if the stress time is longer, it may result in Chinese fir seedlings irreversible damage.In summary, since the toxic substances in the fir salicylic acid and cinnamic acid stress, in the seven tested materials, the fir-resistant clone FS07 and FS21 autotoxicity resistant clones of Chinese fir FS01, FS03, FS04 and intermediate divisions 103, FS13 weakest. Thus, the different clones from the toxic nature of the tolerance of stress were significantly different, which is fit For the future with nurturing the growth of Chinese fir planted on the ground to select superior clones provide a theoretical basis.