Screening Of Combination Initiator For Tomato Rootstock Seeds And The Study Of Its Priming Effect

Tomato(Solanum lycopersicum L.)is one of the most widely cultivated vegetable crops in the world.Seed is an important production material in agriculture,and its pros and cons are directly related to the yield and quality of the product.When the seeds are physiologically mature,the vitality reaches the highest.And when the seeds enter into the storage or dormancy stage,the unsuitable storage conditions or the long storage time cause the seeds to undergo different degrees of deterioration.With the gradually decrease of seed vigor,germination rate will reduce,the germination potential will decrease with a reduced germination uniformity,which will bring losses to agricultural production.Seeds with high vitality have a high germination rate,enhanced germination uniformity and the crops have good resistance and high yield.It shows a growth advantage and production potential.So,it is necessary to maintain and enhance seed vitality.In this experiment,the tomato rootstock variety ’GuoZhen No.1’ was used as the plant material,and the seeds were artificially aged to obtain high,medium and low vigor seeds.Then different concentrations of melatonin(MT),Diethyl aminoethyl hexanoate(DA-6),5-nitroguaiacol sodium(5-NSS),brassinolide(BR),6-benzyladenine(6-BA),5-aminolevulinic acid(ALA),wonncast,tea polyphenols,seaweed extracts were used as single initiator to screen out the three best single initiators;After,the principal components-cluster analysis method was carried out to evaluate the effects of different combinations and screen out the optimal combination initiator.Finally,the physiological and biochemical mechanism of optimal combination initiator to improve seed quality was investigated.The results can provide theoretical basis and practical reference for seed quality improvement.Below are key research contents:1.Obtain tomato seeds with different vitality using artificial aging:the tomato rootstock ’GuoZhen No.1’seeds were placed under artificial aging conditions(40℃,RH 100%),and the seed germination rate and vigor index decreased with the aging time,aging 0,2,3 days,we get high(vigor index is 26.8),medium(vigor index is 14.97)and low(vigor index is 3.99)vigor seeds.2.Screening out single initiator and initiator concentration:We selected 9 single initiators to process the single initiator treatment.The study found that 1 mg·L-1 BR,15 mg·L-1 5-NSS,10 mg·L-1 DA-6 were effectively improved the vigor index of tomato seeds,and which have good priming effects on the three vigor tomato seeds,but 1500 mg·L-1 tea polyphenols,2 × 105 mg·L-1 sputum,5 mg·L-1 ALA suppress the vitality of seeds.3.Screening out initiator combinations:Using the 3 kinds of plant growth regulator single initiators screened from the previous chapter,combined with the optimal macroinitiators initiator chitosan(CTS)and inorganic salt initiator NaCl derived from the previous laboratory results,the single initiator and the combined initiator treatments were used to initiate three vigor seeds.The principal component clustering analysis method was used to analyze and evaluate the triggering effect of different initiator combinations on tomato seeds.For high,medium and low vigor seeds,T7(1 mg·L-1 BR+15 mg·L-1 5-NSS+10 mg·L-1 DA-6)was comprehensively scored the highest,and the score of unprimed control(CK)was always the lowest.4.Group the initiator combination using the cluster analysis:the clustering analysis was carried out for each treatments by using the main component scores as the index to evaluate the triggering effect of the initiator,and the tree diagram according to the cluster analysis can divide the treatment into four groups.The classification was basically the same among the three vigor seeds.First group:BR+5-NSS+DA-6;second group:BR+5-NSS,5-NSS+DA-6,BR+DA-6,BR+CTS+NaCl,5-NSS+CTS+NaC1,DA-6+CTS+NaCl;third group:BR,5-NSS,DA-6;fourth group:CK.5.Initiation effect of the optimal combination initiator on tomato seeds:Three vigor seeds were priming using 1 mg·L-1 BR+15 mg·L-1 5-NSS+10 mg·L-1 DA-6.The study found that the combined initiation increased the soluble sugar and soluble protein content of the seed,which can provide energy and material security for seed germination.It also enhanced the antioxidant function of the seed by enhancing the activity of seed antioxidant enzymes and reducing the content of malondialdehyde;Priming also increases seed proline content,which in turn can increase seed resistance.