Effects Of Temperature On Physiology And Gene Expression Of Narcissus Tazzeta Var. Chinensis In Dormancy Process

Narcissus tazzeta var. chinensis is a flower of Amaryllidaceae Narcissus L. It is one of the ten famous flowers in China, temperature is one of the important factors that influence the dormant process. In this reserach,Narcissus tazzeta var. chinensis was treated at different temperature and researched from three aspects from cell morphology, physiology and biochemistry and molecular biology. all these work lays the foundation of future research.1. Research on the dormancy stage of the Narcissus tazzeta var. chinensis at different temperature.The morphology, anatomy, the change of starch grain, soluble sugar and starch of the Chinese Narsissus are determined using 3 years-old bulbs. The results show that the bulbs is in the enlargement stage during the first 40 days from March 20th to May 19th,2014. Their leaves were green, the weight, height and width of them reached the maximum, the nucleus of the main bud was vital, the starch grains increased gradually and the umbilical point appeared, soluble sugar contentdecreased but the starch content increased. In the 50th day, their leaves faded and left the bulbs, the weight, height and width of them decreased gradually, the nucleus of the main bud was feeble, the umbilical point fade away, the starch grains decreased, the soluble sugar increased and the starch content decreased. Then the repeating test in 2015, the test results show that the bulbs was in deep dormancy in the 60th day. the weight, length and width increased, meanwhile the nucleus of the main bud was rejuvenative, the soluble sugar decreased and the starch content increased.Bulbs were stored at 20℃,25℃,30℃,35℃ during the dormancy. The results show that bulbs were out of dormancy at 20℃. bulbs had entered the dormancy in 60 days at 25℃ treatment. And bulbs had entered the dormancy in 50 days at 30℃, while bulbs had entered the dormancy in 40 days at 35℃. The results are similar in the repeating test in 2015.2. The physiological analysis of the Narcissus tazzeta var. chinensis bud under different temperatures.physiological indexes of Chinese Narsissus leaves and scales were measured in This study. The leaves of Narcissus tazzeta var. Chinensis faded during thedormancy stage. The activity of protective enzyme, MDA and the accumulation of proline can validate the leaf senescence. It was founded that leaves’physiological indexes at 25℃ treatment was highest. With the temperature increasing, the level of MDA increased. The level of MDA of scales was about 4 times higher than the leaves because of earlier accumulation in leaves. With the extension of processing time, the accumulation of proline in leaves and scales went up. The accumulation of proline was positively correlated with temperature. The experiment results show that the accumulation of protective enzyme, MDA and the proline is high in bulbs over 25℃ treatment,, which showed that high temperature is harmful to the leaves.3. Narcissus tazzeta var. chinensis bud dormancy related gene expression analysis at different temperaturein this research,3-year-old Chinese Narsissus buds and leaves of 2014 were used as material and the analysis of related genes was used in real-time QPCR. The results are as follows:in Nature control, NtFT1、NtFT3、NtFT4、NtTIL、NtTIM、 NtCOB2 gene expression came to the peak at enlargement stage in bud, and the highest expression was NtCOBl. bud was treated at 20℃ NtFT1、NtFT3、NtTIM、 NtCOB1、NtCOB2 gene expression were at a peak in enlargement stage, and the lowest expression was NtFT4. When bud was treated at 25℃ NtFT1、NtFT4、 NtTIM、NtCOB1、NtCOB2 gene expression are at peak in bulb enlargement stage. NtTIM keeps the highest expression level in a period of dormancy and NtFT3 always keep in a higher expression level.30℃ treated NtFT1、NtFT3、NtFT4、NtTIM、 NtCOB2 gene expression were at peak of enlargement stage. NtTIM kept the highest expression level in a period of dormancy and NtCOBl kept in a high peak of bulb enlargement.35℃ treated NtFT1、NtFT3、NtFT4、NtTIM、NtCOB1、NtCOB2 gene expression are at enlargement stage in bud. NtTIL and NtTIM keeps highest expression level in a period of dormancy, and NtFT1、NtFT3、NtFT4 are in low expression quantity.AS for leaves under natural condition, NtFT1、NtFT3、NtFT4 expression decreased, NtTIL、NtTIM、NtCOBs at April 19, March 30, April 9 reached a peak respectively. NtFT1, NtFT3, and NtCOBs expression increased at 20℃, NtFT4 changed a little, NtTIL and NtTIM reached peak at April 19th. NtFT1, NtFT3, and NtFT4 expression decreased at 25℃, NtTIL, NtTIM, and NtCOBs at March 30th, April 9th, April 19th reached a peak respectively.30℃’s and 35℃’s NtFT1, NtFT4, NtTIL, and NtTIM expression decreased at both 30℃ and 35℃, NtFT3, NtCOB1, and NtCOB2 increasedand reached the peak in the period from 19th April to 29th May.From the results, NtFTs expression decreased while NtTIL, NtTIM, and NtCOBs increased. The low expression of NtFTs can promote dormancy occurs while NtTIL, NtTIM, and NtCOBs indirectly control dormancy. They play an important role in dormancy of Chinese Narsissus.4. Cloning and Expression analysis of Narcissus tazzeta var. chinensis protective enzymes related gene.Chinese Narsissus leaves were used as material to isolate four protective enzyme gene. The qpcr results showed that NtCAT1 gene reached the highest expression level in March 30th at 30℃ and 35℃, from April 9th to 19th NtPOD2 reached the highest expression. Two NtCSD genes belong to the Cu/ Zn-SOD gene family under 25℃ and 20℃ treatments NtCSD1 and NtCSD2, respectively, reached the highest expression from the April 9th to April 29th. The expression of NtSD2 increased 30,000 times.Compared with the physiological results, CAT activity reached the highest on the April 9th. High expression of NtCatl gene came earlier than physiological indexes, which revealed NtCatl may be the key member to the CAT synthesis genes. Likewise, high expression of NtPOD2 gene came earlier than POD physiological indexes, which showed that NtPOD2 may be involved in the regulation of POD synthesis. The high activity of SOD appeared from April 19th to 29, and NtCSD1 reached the highest expression on March 30th to April 19. The results of expression of NtCSD4 and physiological are not consistent, thus SOD synthesis may be controlled by NtCSDs gene families.