Effects Of Cultivation Substrate And New Growth Regulator On Yield And Quality Of Anoectochilus Roxburghii(Wall.) Lindl.

Anoectochilus roxburghii(Wall.)Lindl is an important medicinal plant in parts of south China and southeast Asian countries,as well as one of the important cash crops.Its growth is restricted by the environment,which is mainly reflected in the cuitivated soil and temperature.Cultivation substrate is an important factor in limiting the industrial production of A.roxburghii.A good cultivation substrate is essential for increasing the survival rate and yield of A.roxburghii after transplanting.In the cultivation process,problems such as poor growth adaptability,insufficient accumulation of medicinal effective components,high temperature,and difficulty in summer during the growth process were prominent,which seriously affected the production of A.roxburghii.Therefore,it is of great significance to select a suitable substrate for the growth of A.roxburghii,improve the content of medicinal effective components,and test the resistance of A.roxburghii to adverse environmental conditions.In this experiment,peat soil,Lentinus edodes residue(the mixture of waste fungus sticks left after harvest of Lentinus edodes),pine bark,coconut bran and fine sand were used to make seven kinds of culture substrates according to a certain volume ratio.Tissue culture seedlings aged five months(TW5)and four months(TW4)were used as mateterials and plant for 120 days.Firstly,the optimal cultivation substrate was selected,and then applied plant growth regulators of melatonin(MT)and γ-aminobutyric acid(GABA)to study the influence of A.roxburghii growth and the accumulation of medicinal effective components.To explore whether MT and GABA can improve the heat resistance of A.roxburghii,we treated A.roxburghii with MT and GABA and treated them under high temperature stress.The main research results are as follows:(1)The growth,yield and quality of Anoectochilus formasamus were significantly affected by different substrates.The matrix formula of peat soil: pine bark: fine sand=2: 2:1(V: V: V)was the most beneficial to increase the yield of A.formasamus.The fresh weight and dry weight of TW5 reached 47.05 g/10 plant and4.43 g/10 plant after 120 days of growth,which were siginificantly higer than other treatments.The matrix formula of residue of lentinus edodes: fine sand = 4:1(V: V)was not conductive for A.formasamus growth.The fresh weight and dry weight of TW5 after 120 days growth were only 26.13 g/10 plant and 2.56 g/10 plant,which were significantly lower than other treatments.Lentinus edodes residue substrate was beneficial to the accumulation of amino acids and alkaloids,and the contents of total amino acids and alkaloids in TW5 were 2.17% and 11.45% respectively after 120 days growth.Pine bark substrate was beneficial to the accumulation of flavonoids,and the content of total flavonoids in TW4 reached 1.55% after 120 days growth.(2)MT and GABA had a significant effect on the growth and accumulation of medicinal effective components.MT and GABA could significantly increase the contents of medicinal effective components of A.roxburghii to a certain extent.The contents of total flavonoids and total amino acids were increased by 27.27% and29.59% under 5 μM MT treatment.The contents of total alkaloids and total amino acids were increased by 28.72% and 44.33% under 5 m M GABA treatment.MT and GABA treatment increased the chlorophyll content,root activity and antioxidant enzyme activity of the seedlings at the initial stage of transplanting.(3)MT and GABA had significant effects on resistance of A.roxburghii to high temperature stress.Short-term heat stress at 12 h,18 h and 24 h had significant effects on physiology and biochemistry of A.roxburghii.and A.formasamus.MT and GABA could improve the heat resistance of the A.roxburghii,mainly through scavenging free radicals,improving the activity of antioxidant enzymes,increasing osmoregulation substance content,reducing membrane lipid peroxidation and leaf water loss to promote the growth of A.roxburghii under high temperature stress.(4)The effect of transplanting bottle seedlings of different seedling ages was significantly different.TW5 is more suitable for transplanting than TW4.The transplanting days of A.roxburghii should be at least 120 days.Peat soil: pine bark:fine sand = 2:2:1(V: V: V)was the most beneficial to increase the yield of A.roxburghii.Plant growth regulators MT and GABA could improve the growth adaptability of A.roxburghii after transplanting,which increase the accumulation of medicinal effective components and improve the resistance to high temperature,thus promoting the growth of A.roxburghii.