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咖啡根系分泌物引起的自毒作用是造成咖啡连作障碍的主要原因,而种间嫁接是抑制咖啡自毒的有效方式。为探明嫁接抑制自毒机制,采用盆栽试验研究咖啡主栽品种根系分泌物对嫁接植株的化感效应。结果表明:根系分泌物抑制了咖啡自根苗生长,且随着根系分泌物浓度升高,抑制作用增强;低浓度根系分泌物能促进咖啡嫁接苗生长,经根系分泌物处理后的嫁接苗株高、根长、地上部干重和根干重分别较未处理的对照嫁接苗平均增加了22.15%、6.52%、44.80%和20.67%,根系活力、叶片保护酶活性也明显增加;高浓度根系分泌物虽未能促进嫁接苗生长,但嫁接苗较自根苗生长优势显著,经根系分泌物处理后嫁接苗POD、CAT和SOD活性分别较自根苗增加了60.61%、27.27%和18.24%,MDA含量显著减少,根系活力显著增加。因此,在根系分泌物处理下,嫁接苗能通过提高自身保护酶活性等方式,促进植株生长或使植株生长所受抑制减少。
The autotoxicity caused by coffee root exudates is the main reason for the obstacle of continuous cropping of coffee, and interspecific grafting is an effective way to inhibit coffee autotoxicity. In order to investigate the grafting inhibition mechanism of autotoxicity, pot experiment was conducted to study the allelopathic effect of root exudates on the grafted plants. The results showed that root exudates inhibited the growth of self-rooted coffee seedlings, and the inhibitory effect was enhanced with the increase of root exudates. Low concentrations of root exudates could promote the growth of coffee-grafted seedlings. After the root exudates were treated, the plant height , Root length, shoot dry weight and root dry weight increased by 22.15%, 6.52%, 44.80% and 20.67% on average compared with the untreated control grafted seedlings respectively. The root activities and the activities of protective enzymes in leaves also increased significantly. Although the grafted seedlings did not promote the growth of grafted seedlings, the grafted seedlings had more advantages than the seedlings. The activities of POD, CAT and SOD of grafted seedlings increased by 60.61%, 27.27% and 18.24% Significantly reduced, root activity increased significantly. Therefore, under the treatment of root exudates, grafted seedlings can promote the growth of plants or reduce the growth inhibition of plants by increasing their own protective enzyme activity.