【作者】 张玉屏；

【导师】 黄义德；

【作者基本信息】 安徽农业大学 ， 作物栽培学与耕作学， 2001， 硕士

【摘要】 水稻生产是农业用水的大户，节水潜力最大；水稻根系作为农作物吸收水分和养分的重要器官，又具有合成、运输和固定植株的作用，其生长与活性和地上部的生长密切相关。针对当今举世关注的焦点问题——水资源的短缺，本试验以籼型杂交中稻协优63（Xieyou63）及籼型常规中稻扬稻6号（YangdaoNo.6）为供试材料，于1999—2000年连续两年在安徽农业大学试验农场标本园旱地和设有遮雨设施的网室中进行盆栽和大田试验，运用植物生理学、生物化学、植物学、植物解剖学及水稻栽培学的原理和方法，系统研究了在旱作条件下根系生长发育特性及其与抗旱性的关系。 盆栽试验，水分处理分3个等级，即对照（CK）、轻度水分胁迫（T₁）、重度水分胁迫（T₂）；设有分蘖期、拔节长穗期、抽穗灌浆期、乳熟期四个处理时期。试验结果表明：轻度胁迫条件下，最有利于根系的生长，根系扎根深，各层分布相对平均，中下层根占总根量的百分比较大，有利于对水分、养分的吸收；根冠比增大，提高耐旱、抗旱能力。 大田试验采取覆膜旱作（PFM）、露地旱作（DC）、常规水作（TPC）3种处理方式，试验表明，各生育时期白根占总根数的百分率均为旱作＞水作，单株不定根总数分蘖期覆膜旱作的最多，露地旱作的与水作的相近，中后期覆膜旱作的与水作的相近，露地旱作的最少。单株根系体积为水作＞覆膜旱作＞露地旱作，单株根系干重前期覆膜旱作＞水作，后期两者相近，以露地旱作为最少。单株最长根长前期旱作的略少于水作，但后期均大于水作处理。根系氧化力在生育期内呈单峰曲线变化，其中以拔节长穗期为最高，且旱作水稻的根系氧化了力明显高于水作。根系吸收总表面积和活跃吸收面积在拔节长穗前同步增大，然后逐渐减小，且活跃吸收面积占总吸收面积的百分比为46％～50％，在前中期，根系总吸收面积和活跃吸收面积水作o覆膜旱作n露地旱作，后期则覆膜旱作＞水作＞露地旱作。旱作水稻根系呼吸强度明显高于水作，此可能是导致旱作水稻比水作水稻早衰严重的原因之一。中后期根系、叶片可溶性糖含量旱作高于水作，有利于提高组织吸水、保水能力，是对干旱适应性的一种表现。根系和叶片根系相对电解质渗透率，在分奠期和拔节初期，旱作与水作相差不大，说明该时期对干旱有较强的适应和调节能力，中后期则明显高于水作，说羽干旱时质膜受害重，耐旱能力差，缺水会导致减产。旱作水稻根系伤流强度在整过生育期内呈双峰曲线，第一高峰出现在有效分菜末期，第二高峰出现在抽穗期，抽穗后各处理的伤流强度下降，且在穗后第17天迅速降低。通过对根系各段的解剖发现，旱作水稻削弱了根系的通气组织，增强了输导和贮藏组织。 通过测定地上部分和灌浆速率知，覆膜旱作叶片存活期长，在乳熟期仍能保持较高的单株绿叶面积；籽粒灌浆高峰期旱作水稻比常规水作提前7天左右，但持续灌浆时间短，籽粒达最大鲜重时间提前。旱作条件下不存在单纯生理上的早衰，生育期较常规水作延长一周左右，且主要在营养生长期，旱作处理的单株有效分蔡数、有效穗数较多，但山于水分胁迫导致功能叶片净光合速率下降，其每穗总粒数、结实率、千粒重均低于常规水作，从最终产量看，覆。萨马作处理与常规水作处理相差不大，不同旱作处理的产量变幅较大，表明覆膜哭作对干旱有良好的适应性。更多还原

【Abstract】 Rice is a staple grain crop in China. Its production stands for about 40% of national grain production. In the north of China, decreasing water shortage limits the development of rice production and the increase of rice yield. It is important to develop the water saving cultivation in rice production to raise and maintain rice production in China. Rice root plays a very important role in the increase of water use efficiency. However, less knowledge about rice root growth and function under dry cultivation is available.This paper studies the root growth characteristics and its relation with leaf growth, yield and its componenets. Experiments were carried out with Xieyou63 and YangdaoNo.6 in the experiment farm of Anhui Agricultural University in 1999 and 2000. In pot experiment. Water content in soil was field capacity(FC)(check,CK)> 65%-70% of FQlight water stress,T1) and 55%-60% of FC(heavy water stress.!,).in the tillering stage, the jointing stage, the heading and grain filling stage, the milk riping stage. In field experiment. Planting type was Dry cultivation with plastic film mulching(PFM), Dry cultivation(DC), Traditional paddy cultivation(TPC). Root samples were taken in different stage through nylon net bag that was embedded in field before planting rice.The results showed that: light water stress stimulated root growth. Compared to check and heavy water stress. Roots grown deeply and percentage of deep root was high and the ratio of root to shoot high. Rice under light water stress shown drought resistance. Rice under PFM had more white roots and its root activity was strong.The total area and active absorption area of roots increased before jointing stage, then decreased. The active absorption area of roots contributed 46-50% of the total absorption area., the respiratory activity of rice roots under dry cultivation and plastic film mulching cultivation was greater than that under water cultivation. This results in leaf senescence of rice under under dry cultivation and plastic film mulching cultivation . Bleeding sap of root appeared with two-peaks curve during the growth period. The first peak appeared at the end of productive tiller, and the second peak heading stage. After heading stage, the bleeding sap of all treatment decreased, but decreased rapidly after 17 day after heading stage.Under PFM, tiller number per plant is higher. But percentage of productive tiller was lower. Root activity under dry cultivation was greater than that with plastic film mulching cultivation. Leaf area index(LAI) of rice under plastic film mulching cultivation was larger that than other treatments, during the milk riping stage. Peak of grain filling under dry cultivation and plastic film mulching cultivation appeared early, grain filling period of rice was shorter than that under traditional padd\ cultivation by about 7 days. Growth duration of rice under dry cultivation and plastic film mulching cultivation was later than Normal paddy field by about ~ dayss Due to the severe leaf senescence by water stress under dry cultivation, the number of grain per panicle, grain fertility and grain weight of traditional p,idd> cultivation was higher . Yield under plastic film mulching cultivation was similar to one under traditional paddy cultivation. Variation of yield under drv cultivation \va;. larger. This showed that yield may be gotten through plastic film mulching cultivation in water shortage region.It was discussed that plastic film mulching dry cultivation for rice is appli x1 in water shortage region and the role of rice root is played in dry cultivation.更多还原