干旱胁迫对玉米根系及植株生长发育影响研究

Effects of Drought Stress on Maize Root System and Plant Growth and Development

为了进一步研究干旱胁迫对玉米根系及植株生长发育的影响,本文对干旱胁迫试验的土壤相对湿度资料、根系资料和生物量资料进行了分析,研究了春玉米不同发育期干旱胁迫对玉米不同土壤深度根系及玉米生物量的影响。结果表明:1) 吐丝期时40 cm土壤深度RD总根长密度为0.36 cm/cm3,D1、D2的总根长密度分别比RD少2%、5%,D3的总根长密度比RD多46%,120 cm土壤深度RD总根长密度为0.07 cm/cm3,D1、D3、D4的总根长密度分别比RD多213%、14%、43%,说明在拔节期间短期控水可以促进根系生长,同时也促进根向深处土壤发展;乳熟期时40 cm土壤深度RD总根长密度为0.20 cm/cm3,D1、D2、D4的总根长密度分别比RD少34%、59%、42%,D3的总根长密度分别比RD多13%,其中D1、D2可能是因早期的干旱根系发展得更深,40 cm土壤深度根系衰老速度比RD快。D4总根长密度小可能是其遭遇干旱比较迟,更多的干物质被植株转移到果穗而加速根系的衰老。D3总根长密度明显较高,可能是因其在结束干旱后复水不久,根的补偿性迅速生长的结果。160 cm土壤深度各组不同直径根长密度占比相差不大,D1、D4的总根长密度分别比RD少46%、37%,D3的总根长密度分别比RD多46%,D3总根长密度高于其他组,这可能是在抽雄期,干旱将促进根向深处生长,复水后又有补偿作用,使其进一步向深处延伸,D4遭遇干旱较晚,根系已过最佳生长阶段,导致其在深层土壤中总根长密度较小。2) 抽雄期时T1与T2叶面积指数分别较CK低6.42%、8.41%,T3叶面积指数比CK高5.31%,T3叶面积指数明显高于其他组,这表明拔节期短时间促进玉米的生长发育,而T1与T2叶面积指数低于CK,则说明拔节期干旱让玉米生长发育不如未遭遇干旱的玉米;至乳熟期,T1、T2、T3叶面积指数分别比CK低46.53%、26.57%、53.21%,说明玉米遭遇干旱后对玉米的生长发育有不好的影响,并且即使是后期复水但造成的影响没有消除,其生长情况还是不如未遭遇干旱的玉米,而T1不如T2则说明越长时间的干旱对于玉米的生长发育影响越严重。3) T1、T2及T3组的总生物量都远小于CK组,其中T2组的总生物量又比T1及T3组稍微大些,T1、T2及T3组的总生物量重分别比CK组低48.15%、30.62%及45.68%,说明干旱对玉米植株生长发育的不利影响与玉米遭遇干旱时间有关,长期干旱比短期干旱的不利影响更大,并且相同的控水时长导致干旱,抽雄期干旱比拔节期干旱对玉米植株生长发育的影响更大,这种不利影响同样也不会因为后面复水而消除。

In order to further study the effects of drought stress on maize root system and plant growth and development, the data of soil relative humidity, roots and biomass in the drought stress experiment were analyzed, and the effects of drought stress on the roots and biomass of maize in different soil depths at different development stages of spring maize were studied. The results showed that: 1) the total root length density of RD in 40 cm soil layer was 0.36 cm/cm3 at silking stage, the total root length density of D1 and D2 was 2% and 5% less than that of RD, respectively, the total root length densities of D3 was 46% more than that of RD, and the RD in 120 cm soil layer was 0.07 cm/cm3. The total root length density of D1,D3 and D4 was 213%, 14% and 43% more than that of RD, respectively, which indicated that short-term water control during jointing period could promote root growth and promote root development into deep soil;at milk stage, the total root length density of RD was 0.20 cm/cm3 at 40 cm soil depth, the total root length density of D1, D2 and D4 decreased by 34%, 59% and 42% respectively compared with RD, and that of D3 increased by 13% respectively. D1 and D2 might develop deeper roots due to early drought. The senescence rate of root system in 40 cm soil depth was faster than that of RD. The low total root length density of D4 may be due to its delayed drought, and more dry matter was transferred by plants to fruit ears, which accelerated root senescence. The total root length density of D3 is significantly higher, this may be the result of the compensatory rapid growth of the roots shortly after the end of the drought byrehydration. The total root length density of D1 and D4 was 46% and 37% less than that of RD, respectively, and the total root length density of D3 was 46% more than that of RD, respectively. The total root length densities of D3 were higher than those of other groups, which may be due to the fact that drought promoted the growth of roots to the depth at the tasseling stage, and there was a compensatory effect after rewatering. As a result, the total root length density of D4 in deep soil was low because of the late drought and the root system had passed the optimal growth stage. 2) At the tasseling stage, the leaf area index of T1 and T2 was 6.42% and 8.41% lower than that of CK, respectively, and the leaf area index of T3 was 5.31% higher than that of CK, which indicated that the jointing stage promoted the growth and development of maize in a short time, while the leaf area indexes of T1 and T2 were lower than those of CK. It shows that the drought in jointing stage makes the growth and development of maize worse than that of maize without drought;at the milk stage, the leaf area index of T1, T2, T3 were 46. 53%, 26.57% and 53.21% lower than CK, respectively, indicating that drought had a negative impact on the growth and development of maize, and even after rewatering in the late period, the growth of maize was still not as good as that of maize without drought. However, T1 was not as good as T2, indicating that the longer the drought, the more seri-ous the impact on the growth and development of maize. 3) The total biomass of T1, T2 and T3 was much less than that of CK, and the total biomass of T2 was slightly larger than that of T1 and T3, and the total biomass weight of T1, T2 and T3 was 48.15%, 30.62% and 45.68% lower than that of CK, respectively. The results showed that the adverse effects of drought on the growth and development of maize plants were related to the time of drought encountered by maize, and the adverse effects of long-term drought were greater than those of short-term drought, and the same length of water control led to drought, the impact of drought at tasseling stage on the growth and development of maize plants was greater than that at jointing stage, and this adverse effect would not be eliminated by rewatering later.