Study On Sorting Technology To Enhance Seeds Quality Of Main Afforestation Tree Species In South China

Seeds are unique propagule of gymnosperms and angiosperms, the base of the agricultural production. Seeds are not only the most important means of production, but also are the foundation of human survival and development. The advantages and disadvantages of seed quality not only affects crop yield, but also affect the quality of the crop. But many reasons affect seed quality, seed gene, pollination, fertilization, environmental factors in the seed development process, insect infestation etc. Because of these effects of force majeure, collected tree seeds include empty seeds, abortive seeds and other seeds which can not germinate. Therefore, we have great demand for high-quality tree seeds. How to remove these seeds which can’t germinate is very necessary and urgent.We have high forest coverage rate and big plantation area. Accord to the seventh inventory of the national forest resources, we have195million hectares of forest area. Main afforestation tree species such as Chinese fir, masson pine, slash pine and loblolly pine, accounting for57%of the man-made plantation area. Compare with forestry developed countries, our forestry productivity level is low, extensive operation, lack of investment in science and technology, seeds sorting technology research and application did not get enough attention, resulting in low seed germination. Therefore, demand for high quality tree seeds are very urgent, launch tree seed sorting technology research is important theoretical and practical significance for sustainable forestry in China.In view of this, we consider Chinese fir seeds, masson pine seeds, slash pine seeds and loblolly pine seeds as the research object, selecting different hydropriming temperature, hydropriming noisture, hydropriming time, to find appropriate hydropriming condition for different species. Based on this selection, we can determine the appropriate drying time for different species, improve the conditions of the IDS sorting technology. After scaning different kinds of seeds, analysising different separation results which are from different wavelengths and discrimination models for different seeds, we can find suitable near infrared spectroscopy conditions for various species. Establishing suitable seeds sorting technolog for practical forestry production has important theoretical and practical significance for enhance the quality of seeds of main afforestation tree species in southern China. The main findings are as follows:1. We select different hydropriming temperature, hydropriming noisture, hydropriming time, to find appropriate hydropriming condition for different species. The results showed that different species have different hydropriming condition. Hydropriming noisture40%, hydropriming temperature10℃, hydropriming time7d is the appropriate hydropriming condition for Chinese fir seeds. Hydropriming noisture35%, hydropriming temperature15℃, hydropriming time7d is the appropriate hydropriming condition for masson pine seeds. Hydropriming noisture40%, hydropriming temperature15℃, hydropriming time14d is the appropriate hydropriming condition for slash pine seeds. Hydropriming noisture40%, hydropriming temperature15℃, hydropriming time7d is the appropriate hydropriming condition for loblolly pine seeds.2. Hydropriming sorting technology can notablely enhance germination rate (GR). The GR of primed Chinese fir seeds has increased13.77%than unprimed seeds, the MGT of primed Chinese fir seeds has increased1.30d than unprimed seeds. The GR of primed masson pine seeds is35.33%more than unprimed seeds, the MGT of primed masson pine seeds is2.92d more than unprimed seeds. The GR of primed slash pine seeds has increased4.74%than unprimed seeds, the MGT of primed slash pine seeds has reduced2.82d than unprimed seeds. The GR of primed loblolly pine seeds is12.82%more than unprimed seeds, the MGT of primed loblolly pine seeds is1.17d less than unprimed seeds.3. In the drought treatment and artificial aging treatment, contrasting germination rate, mean germination time, seed lixivium conductivity betweed primed seeds and unprimed seeds, we can see that, with the enhancement of the stress intensity, germination capacity of masson pine seeds, slash pine seeds and loblolly pine seed are on the decline. Under the same stress intensity, contrasting primed seeds and unprimed seeds, we can find that primed seeds have higher germination capabilities, higher drought-resistant and anti-aging abilities.4. We can determine the appropriate drying time, build the suitable IDS sorting technology for different species. Hydropriming noisture40%, hydropriming temperature10℃, hydropriming time7d, drying time2h is the appropriate IDS sorting technology condition for Chinese fir seeds, we can collect the sunk seeds in water. Hydropriming noisture35%, hydropriming temperature15℃, hydropriming time7d, drying time4h is the appropriate IDS sorting technology condition for masson pine seeds, we can collect the sunk seeds in water. Hydropriming noisture40%, hydropriming temperature15℃, hydropriming time14d, drying time4h is the appropriate IDS sorting technology condition for slash pine seeds, we can collect the sunk seeds in water. Hydropriming noisture30%, hydropriming temperature10℃, hydropriming time7d, drying time4h is the appropriate IDS sorting technology condition for loblolly pine seeds, we can collect the sunk seeds in water.5. IDS sorting technology can notablely enhance germination rate (GR). The GR of sorted Chinese fir seeds has increased27.19%than unsorted seeds, the MGT of sorted Chinese fir seeds has increased1.54d than unsorted seeds. The GR of sorted masson pine seeds has increased37.23%than unsorted seeds, the MGT of sorted masson pine seeds has increased0.64d than unsorted seeds. The GR of sorted slash pine seeds has increased5.15%than unsorted seeds, the MGT of sorted slash pine seeds has increased2.94d than unsorted seeds. The GR of sorted loblolly pine seeds has increased5.84%than unsorted seeds, the MGT of sorted loblolly pine seeds has increased2.25d than unsorted seeds. IDS sorting technology can markedly improve the quality of seeds of main afforestation tree species in southern China.6. Near-infrared sorting technology can identify different vigor of Chinese fir, masson pine, slash pine and loblolly pine seeds, the technology can be used as a new technology to authenticate tree seed germplasm resources.7. We can establish a new way to identify seed vigor, by matchuping water content difference between dead-filled and viable-filled seeds with for detection by NIR. By analysising different separation results which are from different wavelengths and discrimination models for different seeds, we can find suitable conditions for various species. Wavelengths range is780-2500nm, analysing with PLS-DA, distinguishability is0.5nm, scan times32are appropriate for clear separation of empty and filled seeds of Chinese fir. Wavelengths range is780-1100nm, analysing with PLS-DA or OPLS-DA, distinguishability is0.5nm, scan times32are appropriate for clear separation of dead-filled and viable-filled seeds of mason pine. Wavelengths range is780-2500nm or1100-2500nm, analysing with PLS-DA or OPLS-DA, distinguishability is0.5nm, scan times32are appropriate for clear separation of dead-filled and viable-filled seeds of slash pine. Wavelengths range is780-2500nm, analysing with OPLS-DA, distinguishability is0.5nm, scan times32are appropriate for clear separation of dead-filled and viable-filled seeds of loblolly pine. 8. Choose different sorting techniques based on different purposes. If we want to improve seed quality in a short period of time, we’d better choose hydropriming technology. We can remove empty seeds by using IDS technology. We can use NIR sorting technology if we sort single seed.