玉米耐铝性研究Ⅱ．玉米耐铝机理及培养条件对其耐性的影响

STUDIES ON ALUMINIUM TOLERANCE INCORN CULTIVARS Ⅱ.MECHNlSMS OF ALUMINUM TOLERANCE IN CORN AND EFFECTS OF CULTURE CONDITIONS ON ITS TOLERANCE TO ALUMINIUM

研究了耐铝基因型７３单交，半耐铝基因型丹玉１１号和铝敏感基因型７５－２４×３３０玉米根冠含铝量、根系活力和根部呼吸强度的差异．三者根、冠含铝量分别为４２４．７和１．７，２５５．９和２．６，４１５．９和６７．６μｇＡｌ／ｇ鲜重；其单克鲜根和单株的相对根系活力分别为１３３．１４％和９６．１１％，１１１．６０％和５４．７６％以及９４．１２％和３３．４２％．当培养液中Ｃａ２＋浓度由０，５提高到２．０ｍｍｏｌ／Ｌ时，三类基因型玉米的相对根长显著或极显著地增加，根部含铝量都显著下降，耐性和半耐性基因型玉米根部呼吸强度处理与对照间相差无几，而敏感基因型玉米则处理较对照提高３９．２９％．这表明７３单交玉米主要是通过增强根部的呼吸代谢和根系活力，阻碍Ａｌ３＋运往地上部来实现其耐铝性的。提高Ｃａ２＋水平能显著地缓解铝的毒害．

Aluminum contents in roots and shoots, root activity and respiratory rate of 3genotypes were determined in the same culture method as the previous report.Aluminumcontents in roots and shoots of the tolerator,73 Danjiao,simi-tolerator,Danyu No. 11 andsenstive one,75-24X330 were 424.7 and 1.7,255.9 and 2.6 and 415.9 and 67.6μgAl/gFW in colorimetrical way,their relative(Al/CK)root activity per gram and per plant in TTCmethod was 133.14%and 96.11%,111.6%and 54.76%and 94.12%and 33.42%respec-tively,and the tolerator’s respiratory rate got 30.43%higher in the treatment than that inthe control and the other two changed in no significance. When Ca2+level in the growth solu-tion was added to 2.0 from 0.5 mmol/L the relative root length of the 3 was significantly orextremelyy significantly increased and aluminum contents in root of the 3, on the contrary,were obviously decreased.Respiratory rates in root in the treatment and control of the tole-rant and semi-tolerant ones were changed little but the senstive one was enhanced by39.29%. This indicates that the tolerant ones such as 73 Danjiao tolerates aluminium toxici-ty by increasing root respiratory rate and root activity and preventing Al3+from being trans-ported to shoot from root. Higher Ca2+concentration in the growth medium may alleviate a-luminium toxicity to crop plants.