不同滴灌模式对东北春播玉米籽粒淀粉积累及淀粉相关酶活性的影响

2022-04-14张家桦杨恒山张玉芹李从锋张瑞富邰继承周阳晨

中国农业科学 2022年7期

张家桦，杨恒山，张玉芹，李从锋，张瑞富，邰继承，周阳晨

张家桦1，杨恒山1，张玉芹1，李从锋2，张瑞富1，邰继承1，周阳晨1

1内蒙古民族大学农学院，内蒙古通辽 028000；2中国农业科学院作物科学研究所，北京 100081

【】探明不同滴灌模式对春玉米籽粒淀粉积累及淀粉合成相关酶活性的影响，为提高春玉米产量提供理论指导。以农华101为试验材料，采用裂区试验，主处理为滴灌模式，设膜下滴灌和浅埋滴灌2种，副处理为灌水量，设传统灌水量40%（W1：1 440 m3·hm-2）、传统灌水量50%（W2：1 800 m3·hm-2）和传统灌水量60%（W3：2 160 m3·hm-2）3 个水平，于苗期—拔节期、拔节期—大喇叭口期、大喇叭口期—吐丝期、吐丝期—乳熟期、乳熟期—收获按照1﹕2﹕2﹕3﹕2比例滴灌。吐丝后20 d开始，每7 d取玉米籽粒1次，采用酸水解-DNS法测定玉米籽粒中总淀粉含量，采用淀粉合成酶试剂盒测定腺苷二磷酸葡萄糖焦磷酸化酶（AGPase）、结合态淀粉合成酶（GBSS）、可溶性淀粉合成酶（SSS）活性，研究玉米籽粒产量、淀粉积累量特征及AGPase、GBSS、SSS酶活性变化。2019—2020年春玉米有效穗数和穗粒数两种模式间差异不显著， W1处理浅埋滴灌千粒重和产量低于膜下滴灌，W2处理二者无显著性差异，W3处理显著高于膜下滴灌，其中产量分别高5.7%和8.4%，千粒重分别高11.9%、12.1%。方差分析表明，灌水量、滴灌模式和灌水量与滴灌模式互作对千粒重影响差异达显著、极显著水平，年份、灌水量及灌水量与滴灌模式互作对籽粒产量影响达到显著或极显著水平。W1处理浅埋滴灌籽粒淀粉含量和积累量低于膜下滴灌，W2处理从吐丝后20 d起浅埋滴灌低于膜下滴灌，吐丝后55 d二者差异不显著，W3处理吐丝41 d前低于膜下滴灌，随生育进程差异减小，吐丝后55 d显著高于膜下滴灌。3个灌水量下浅埋滴灌的籽粒淀粉活跃积累期较膜下滴灌时间长，且籽粒淀粉积累达到最大速率的时间较膜下滴灌时间延后。活跃积累期对淀粉最终积累量影响系数最大，其次为达到最大速率的时间，生育后期淀粉积累速率与籽粒淀粉总积累量极显著相关、与产量显著相关。浅埋滴灌下吐丝后20—27 d AGPase、GBSS和SSS 3种酶活性3个灌水量下均低于膜下滴灌，随生育进程推移差异减小，从吐丝后48 d起W3处理高于膜下滴灌，吐丝后55 d W1和W2处理亦高于膜下滴灌。除W1处理下籽粒淀粉积累速率与AGPase焦磷酸化酶无显著性相关外，其他处理籽粒淀粉积累速率与AGPase、GBSS、SSS酶活性呈显著性正相关。在传统灌水量60%时，浅埋滴灌下春玉米籽粒灌浆后期淀粉合成相关酶（AGPase、GBSS、SSS酶）活性强、淀粉活跃积累期延长，淀粉积累能力增强，千粒重增加，籽粒产量最高。浅埋滴灌优化灌溉可通过提高籽粒灌浆后期淀粉合成酶活性，增强淀粉积累能力，进而增加粒重、提高产量，达到节水增效的目的。

滴灌模式；春玉米；籽粒；酶活性；淀粉积累

0 引言

【研究意义】西辽河平原地处世界玉米生产的“黄金带”，是我国为数不多的井灌玉米高产区之一[1]，井灌玉米面积占80%以上，灌溉水用量大，导致区域地下水位下降明显[2]，发展节水农业，提高灌溉水利用效率是西辽河平原灌区玉米生产发展的必然选择。膜下滴灌作为东北地区节水灌溉的主推技术，在半干旱地区籽粒产量和水分利用率显著提高[3]，但随其种植面积的扩大和种植年限的延长，残膜量的增加导致各土层出现不同程度的水分亏缺，土壤容重增加，产生水分优势流或水分阻隔效益[4]，且大量的残膜导致根系下扎困难[5-6]，生育后期出现一定程度的早衰，在偏砂型土壤上表现较为明显[7]。浅埋滴灌是本研究团队协同研发的一种新型滴灌技术，地表无膜覆盖、滴灌管浅埋于地表（3—5 cm），在发挥滴灌技术优势的同时，也避免残膜污染等问题，具有较大的实际应用价值[8]，2018年—2020年在内蒙古东部推广面积超过1 300万亩，取得了显著的经济效益和生态效益。浅埋滴灌由于地表无膜覆盖，土壤水、热变化规律与膜下滴灌差别较大，两种滴灌模式下玉米产量形成机理必然存在差异。淀粉的积累是决定玉米产量的重要因素之一[9]，淀粉的合成过程需要多种酶参与，探明不同滴灌模式对春玉米籽粒淀粉积累及淀粉合成相关酶活性的影响，是节水条件下加深理解玉米产量形成过程的重要生理基础。【前人研究进展】淀粉作为玉米籽粒的主要储藏物质，占玉米总质量的70%左右[10]，其数量多少直接影响玉米的产量[11]。胡文河等[12]对不同株型玉米籽粒淀粉积累的研究表明，淀粉积累能力较强的品种，产量显著增加。陈江等[13]研究指出，淀粉合成积累受淀粉合成相关酶调控，玉米发育中后期淀粉合成相关酶活性受到影响，则淀粉合成受阻，籽粒干重下降，产量降低。从淀粉合成相关酶对淀粉形成机理的研究发现，腺苷二磷酸葡萄糖焦磷酸化酶（ADPase）、可溶性淀粉合成酶（SSS）和结合态淀粉合成酶（GBSS）对淀粉的合成与代谢起关键性作用[14-15]，在淀粉合成时，ADPase用来催化葡萄糖供体腺苷二磷酸葡萄糖（AGPG）的形成，是淀粉合成过程中的限速酶[16]，AGPase活性与淀粉积累量呈显著或极显著正相关[17]，SSS是催化合成支链淀粉的关键酶，较强的SSS活性有利于提高AGPase合成淀粉的能力[18]，GBSS催化淀粉链的延长，对直链淀粉积累起重要作用[19]。已有大量对不同作物中AGPase、GBSS、SSS酶活性变化的文献报道，水稻中研究表明，密度、温度、水分等对3种酶活性均有影响[20-21]，小麦中研究指出，高温、渍水、遮荫、非充分灌溉等均降低3种酶活性[22-25]，玉米中研究发现，适宜的水分供应可以提高5种酶的活性，促进淀粉合成[26]，水分亏缺使AGPase、GBSS、SSS酶的结构发生破坏，淀粉合成受阻[27]。【本研究切入点】栽培措施及环境因素对淀粉合成相关酶及淀粉积累影响较大，浅埋滴灌和膜下滴灌两种模式下，土壤温度、水分分布及运移特征存在明显差异[28]，对淀粉合成相关酶活性及淀粉合成与积累势必产生影响，目前针对两种滴灌模式下春玉米籽粒淀粉积累及淀粉相关酶活性研究尚未见报道。【拟解决的关键问题】本文在膜下滴灌和浅埋滴灌两种模式下，设传统灌水量40%，传统灌水量50%，传统灌水量60% 3个灌水量水平，研究两种滴灌模式对春玉米灌浆期籽粒淀粉积累及相关酶活性的影响，以期为东北区春播玉米节水高产栽培提供理论依据。

1 材料与方法

1.1 试验区概况

试验于2019—2020年在通辽市科尔沁区农牧业高新科技示范园区进行，试验地土壤为灰色草甸中壤土，是当地主要的土壤类型。2019—2020年0—20 cm土壤表层养分含量分别为有机质18.27 g·kg-1和19.05 g·kg-1、碱解氮51.13 mg·kg-1和52.9 mg·kg-1、全氮0.75 g·kg-1和0.78 g·kg-1、有效磷6.26 mg·kg-1和6.03 mg·kg-1、速效钾77.85 mg·kg-1和81.05 mg·kg-1。

1.2 试验设计

本试验以农华101为试验材料，采用裂区试验，滴灌模式为主处理，设浅埋滴灌和膜下滴灌2种，灌水量为副处理，设传统灌水量40%（W1：1 440 m3·hm-2），传统灌水量50%（W2：1 800 m3·hm-2），传统灌水量60%（W3：2 160 m3·hm-2）3个水平，按苗期—拔节期、拔节期—大喇叭口期、大喇叭口期—吐丝期、吐丝期—乳熟期、乳熟期—收获1﹕2﹕2﹕3﹕2比例滴灌。具体灌溉方案如表1。

各处理采用播种-施肥-铺带-覆膜一体机播种，浅埋滴灌播种时抬起覆膜装置，大小垄（小垄行距40 cm，大垄行距80 cm）种植，种植密度为7.5万株/hm2，播后统一滴引苗水400 m3·hm-2。浅埋滴灌和膜下滴灌均采用贴片式滴灌管，滴头相距20 cm，膜下滴灌地膜采用宽为1.2 m，厚度为0.08 mm的聚乙烯透明膜。各处理底施磷酸二铵150 kg·hm-2，硫酸钾90 kg·hm-2，追施尿素525 kg·hm-2，分别在拔节期、大喇叭口期、吐丝期按3﹕6﹕1比例结合滴灌追施，追肥前先滴清水0.5 h，拔节期灌溉结束前1.5 h加入氮肥，大喇叭口期在灌溉结束前3 h加入氮肥，吐丝期在灌溉结束前2 h加入氮肥，施肥结束后，继续滴灌0.5 h。小区面积120 m2（6 m×20 m），3次重复。各处理2019年5月1日播种，10月1日收获，2020年5月3日播种，10月2日收获。

表1 不同滴灌模式灌溉方案

W1：传统灌水量40%；W2：传统灌水量50%；W3：传统灌水量60%；MDI：膜下滴灌；SBDI：浅埋滴灌。下同

W1: 40% of traditional irrigation; W2: 50% of traditional irrigation; W3: 60% of traditional irrigation; MDI: mulched drip irrigation; SBDI: Shallow burial drip irrigation. The same as below

于吐丝期，各小区选择同日吐丝且健壮一致的植株40株进行标记。自吐丝后20—55 d（8月10日至9月14日），每隔7 d各处理取果穗3株，每穗均匀取籽粒200粒，100粒直接放入液氮中冷冻，另外100粒直接进行105℃杀青，然后放入烘箱85℃烘干后称重。

1.3 测定项目与方法

1.3.1 淀粉含量采用酸水解-DNS[29]法测定植物样品中总淀粉含量。

1.3.2 AGPase、GBSS、SSS酶活性测定称取0.100—0.200 g样品，加入1 mL 提取液，冰浴中匀浆。10 000 ×4℃离心10 min，弃上清，在沉淀中加入1 mL提取液充分混匀，置冰上待测。采用淀粉合成酶试剂盒（上海索桥生物科技有限公司）分别测定AGPase、GBSS、SSS酶活性。

1.4 数据处理

采用Excel 2019进行数据处理和作图，DPS18.10软件进行通径分析、差异显著性（LSD）分析。

2 结果

2.1 不同滴灌模式下灌水量对玉米产量的影响

由表2可知，2019—2020年，两种滴灌模式在不同灌水量下有效穗数与穗粒数均表现为无显著性差异；W1处理浅埋滴灌千粒重低于膜下滴灌，W3处理浅埋滴灌千粒重显著高于膜下滴灌；两种滴灌模式下玉米产量均随灌水量的增加而增加，整体表现为W3＞W2＞W1，W1处理浅埋滴灌产量低于膜下滴灌，W2处理浅埋滴灌与膜下滴灌无显著性差异，W3处理浅埋滴灌产量较膜下滴灌分别高5.7%、8.4%，千粒重分别高11.9%、12.1%。

表2 不同滴灌模式下玉米产量及其构成因素

不同小写字母表示同一年内同灌水量不同滴灌模式差异显著（＜0.05）。下同

The different lowercase letters indicate difference at 0.05 level under the same irrigation amount and different drip irrigation modes in the same year. The same as below

由表3方差分析结果可知，灌水量、滴灌模式和灌水量与滴灌模式互作对千粒重影响差异达显著或极显著水平，年份、灌水量及灌水量与滴灌模式互作对籽粒产量影响达到显著或极显著水平。说明不同滴灌模式下灌量对产量和千粒重影响较大。

2.2 不同滴灌模式下灌水量对玉米籽粒淀粉积累的影响

2.2.1 籽粒淀粉含量两种滴灌模式不同灌水量春玉米籽粒淀粉含量随生育进程逐渐升高，不同灌水量下表现为W3＞W2＞W1（图1）。W1、W2处理吐丝后20 d膜下滴灌籽粒淀粉含量高于浅埋滴灌，随生育进程差异逐渐缩小，W2处理吐丝后55 d二者无显著性差异；W3处理在吐丝后20—27 d膜下滴灌高于浅埋滴灌，随生育进程差异减小，吐丝后41 d（8月31日）二者无显著差异，吐丝后55 d浅埋滴灌显著高于膜下滴灌。

2.2.2 籽粒淀粉积累量春玉米籽粒淀粉积累量趋势呈“S”型曲线，淀粉积累趋势与淀粉含量趋势基本一致（图2）。W1处理在灌浆后期膜下滴灌显著高于浅埋滴灌，这可能由于水量亏缺下，膜下滴灌具有保水作用，进而导致淀粉积累量高于浅埋滴灌；W2处理吐丝后34—48 d膜下滴灌显著高于浅埋滴灌，吐丝后55 d二者无显著性差异，说明灌水量的增加使浅埋滴灌生育后期积累量迅速增加；W3处理在吐丝后27—34 d膜下滴灌高于浅埋滴灌，吐丝后41 d二者无显著性差异，随后浅埋滴灌籽粒淀粉积累量迅速升高，至吐丝后55 d二者差异显著，浅埋滴灌较膜下滴灌高15.8%。

表3 不同滴灌模式下玉米千粒重、产量方差分析

W1：传统灌水量40%；W2：传统灌水量50%；W3：传统灌水量60%；MDI：膜下滴灌；SBDI：浅埋滴灌。下同

图2 不同滴灌模式与灌水量对玉米籽粒淀粉积累量的影响

2.2.3 籽粒淀粉积累参数利用Richard方程对玉米籽粒淀粉积累量与取样天数进行拟合，可很好地模拟出不同滴灌模式不同灌水量下籽粒淀粉积累动态（2=0.993—0.998），计算得到活跃积累期、最大积累速率、平均积累速率、达到最大速率的时间相关参数。从表4可知，3个灌量下浅埋滴灌的籽粒淀粉活跃积累期较膜下滴灌时间长，灌水量越高越明显；籽粒淀粉积累达到最大速率的时间较膜下滴灌时间延后，最大积累速率和平均积累速率W3处理高于膜下滴灌。

表4 不同滴灌模式下玉米籽粒淀粉积累模型及参数

2.2.4 籽粒淀粉总积累参数通径分析根据Richard方程拟合参数X1（活跃积累期）、X2（平均积累速率）、X3（最大积累速率时积累量）、X4（最大积累速率）、X5（起始积累势）、X6（达到最大速率的时间）、X7（淀粉总积累量）进行通径分析。由表5可知，X1、X2、X4、X6 4个因素对淀粉最终积累量的直接效应为正值，促进籽粒淀粉积累，X1、X2、X4、X6对淀粉总积累量的影响系数分别为2.6396、2.6254、0.9173、2.5594。

2.2.5 籽粒淀粉积累速率与淀粉总积累量、产量相关分析利用Richard方程拟合籽粒淀粉积累量得到灌浆前期积累速率、灌浆中期积累速率、灌浆后期积累速率，用3个参数与淀粉积累量和产量进行相关性分析。由图3可以看出，灌浆中期积累速率与淀粉总积累量、产量呈显著相关（2=0.8877、2=0.8051），灌浆后期积累速率与籽粒淀粉总积累量、产量呈显著相关（2=0.8916、2=0.8072）。说明灌浆后期淀粉积累速率是影响产量的重要因素。

表5 不同滴灌模式与灌水量对玉米籽粒淀粉积累参数通径分析

X1：活跃积累期；X2：平均积累速率；X3：最大积累速率时积累量；X4：最大积累速率；X5：起始积累势；X6：达到最大速率的时间

X1: Active accumulation period; X2: Average accumulation rate; X3: Accumulation amount at maximum accumulation rate; X4: Maximum accumulation rate; X5: Initial accumulation potential; X6: Time to reach maximum rate

*, P＜0.05

2.3 不同滴灌模式下灌水量对玉米籽粒淀粉合成代谢酶活性的影响

2.3.1 籽粒AGPase 活性由图4可知，吐丝后20—55 d，籽粒AGPase酶的活性随生育进程先升高后降低，两种滴灌模式不同灌水量下均表现为W3＞W2＞W1。同一灌水量下，两种滴灌模式相比较，W1处理AGPase酶活性除吐丝后55 d外，均为膜下滴灌高于浅埋滴灌，吐丝后48 d二者差异最大，膜下滴灌较浅埋滴灌高15.9%；W2处理吐丝后41 d前膜下滴灌高于浅埋滴灌，吐丝后48 d二者无显著性差异，吐丝后55 d浅埋滴灌较膜下滴灌高12.0%；W3处理吐丝后20—41 d二者酶活性的影响差异不显著，吐丝后48—55 d浅埋滴灌显著高于膜下滴灌，其中，吐丝后55 d浅埋滴灌较膜下滴灌高15.8%。浅埋滴灌前期AGPase酶活性相对较低，生育后期AGPase酶活性高于膜下滴灌，灌水量越大，超越膜下滴灌的时间越早，说明浅埋滴灌生育后期酶活性持续时间长，增加了淀粉合成底物的供应，进而增加淀粉的合成。

2.3.2 籽粒GBSS活性由图5可知，两种滴灌模式不同灌水量下籽粒GBSS活性表现为W3＞W2＞W1。同一滴灌量下，两种滴灌模式相比较，W1处理籽粒GBSS活性在吐丝后20—41 d膜下滴灌高于浅埋滴灌，吐丝后48 d差异不显著，吐丝后55 d浅埋滴灌较膜下滴灌高17.2%；W2处理吐丝后20—34 d膜下滴灌高于浅埋滴灌，吐丝后41—48 d二者差异不显著，吐丝后55 d浅埋滴灌较膜下滴灌高22.9%；W3处理吐丝后20—27 d膜下滴灌高于浅埋滴灌，吐丝后34—41 d二者无显著性差异，吐丝后48 d和55 d浅埋滴灌分别较膜下滴灌高18.0%、17.0%。说明生育后期浅埋滴灌GBSS活性降低速度小于膜下滴灌，不同灌水量下超越膜下滴灌的时间不同，灌水量越大超越时间越早。

图4 不同滴灌模式下与灌水量对玉米籽粒AGPase焦磷酸化酶活性的影响

图5 不同滴灌模式与灌水量对玉米籽粒GBSS结合态淀粉合成酶活性的影响

2.3.3 籽粒SSS活性由图6可看出，两种滴灌模式在3个灌水量下春玉米籽粒SSS活性变化趋势与GBSS活性基本一致。但浅埋滴灌下后期SSS活性较GBSS活性升高幅度大，吐丝后55 d浅埋滴灌W1处理SSS活性较膜下滴灌增加24.9%，W2处理增加34.8%，W3处理吐丝后48 d、55 d分别较膜下滴灌高26.0%、30.7%。两种滴灌模式下，浅埋滴灌较膜下滴灌酶活性持续时间长，生育后期浅埋滴灌下酶能够更好发挥作用，催化淀粉的合成。

2.3.4 淀粉积累速率与淀粉合成酶活性相关性对两种滴灌模式下不同灌水量春玉米籽粒淀粉积累速率与淀粉合成相关酶活性进行相关性分析（图7），除W1处理下籽粒淀粉积累速率与AGPase酶无显著性相关外，其他处理籽粒淀粉积累速率与AGPase、GBSS、SSS酶活性呈显著性正相关（2=0.7395— 0.9651），这表明提高AGPase、GBSS、SSS酶活性，有利于籽粒淀粉的积累，提高粒重，进而提高产量。

3 讨论

籽粒增重的过程主要是淀粉合成与积累的过程[27]，淀粉积累量直接影响籽粒产量[12]，籽粒发育过程中，不同的栽培模式以及环境条件均会影响籽粒淀粉的积累，最终影响产量[27, 30]。研究表明，小麦水分亏缺或温度过高，淀粉含量与积累量下降，产量显著降低[31-32]，充足滴灌条件下淀粉含量、积累量增加，产量提高[33-34]。玉米籽粒淀粉积累受到抑制后，淀粉产量及籽粒产量严重下降[35]。本研究中，灌浆期不同滴灌模式下籽粒中淀粉生物合成效率不同是粒重和产量差异的重要原因，浅埋滴灌W1处理下籽粒淀粉积累量低于膜下滴灌，千粒重下降，产量降低，W3处理前期差异较小，吐丝后55 d显著高于膜下滴灌，千粒重提高，产量增加。淀粉积累存在差异的原因可能是膜下滴灌提高地温，促进春玉米苗期的生长发育[36]，导致生育进程加快。吐丝后20—48 d，膜下滴灌淀粉积累高于浅埋滴灌，吐丝后55 d膜下滴灌淀粉积累低于浅埋滴灌，这可能是膜下滴灌生育后期植株出现一定程度的早衰[7, 37]，导致生育后期淀粉合成下降。浅埋滴灌W1处理下生育后期由于灌量不足籽粒淀粉合成效率较低，W3灌水量下生育前期淀粉积累略低于膜下滴灌，但生育后期由于地表无膜覆盖避免了春玉米后期根冠早衰问题，且其灌溉充足，维持较高的淀粉合成效率，淀粉积累量高于膜下滴灌。本文中Richard方程模拟表明，灌量达到传统灌水量60%时，浅埋滴灌较膜下滴灌淀粉积累达到最大速率的时间延后，活跃积累期延长，灌浆后期积累速率与籽粒淀粉总积累量呈极显著相关（2=0.8916）、与产量呈显著相关（2=0.8072），吐丝后55 d W3处理下淀粉积累量膜下滴灌显著低于浅埋滴灌，这也进一步说明浅埋滴灌下W3处理生育后期淀粉合成与积累能力较强，是其产量增加的原因之一。

图6 不同滴灌模式与灌水量对玉米籽粒SSS可溶性淀粉合成酶活性的影响

*, P＜0.05; **, P＜0.01

籽粒淀粉的合成过程是一个多种酶参与的过程，Jenner等[38]研究认为，籽粒淀粉积累主要受酶活性及合成底物的影响，淀粉合成酶起着至关重要的作用[39]。李永庚等[40]对冬小麦研究表明，AGPase酶与淀粉积累速率呈正相关，是影响粒重的关键酶。王龙飞等[35]研究发现，玉米籽粒中AGPase酶是淀粉合成的关键酶和限速酶，玉米bt2/bt2/bt2 胚乳突变体缺失AGPase酶活性后籽粒淀粉含量下降83%[41]，玉米果穗顶部籽粒AGPase焦磷酸化酶活性峰值和平均值均显著低于果穗中、下部籽粒，上部籽粒淀粉积累量低，是其粒重低于中、下部籽粒的主要原因[42]。本研究中，浅埋滴灌W3处理吐丝后55 d玉米籽粒AGPase焦磷酸化酶活性显著高于膜下滴灌，籽粒淀粉积累量较高，说明籽粒AGPase酶活性对籽粒淀粉积累起重要调节作用。研究表明，GBSS、SSS 活性对籽粒淀粉积累起重要调节作用[43]，其活性与籽粒淀粉的积累[44]和粒重的增加有密切关系[45]，GBSS、SSS的活性降低后，淀粉的合成会受到阻碍，降低淀粉积累速率[46]。曹颖妮等[47]研究表明，小麦籽粒淀粉积累速率随着籽粒中GBSS、SSS酶的活性升高而增加。刘霞等[48]指出，小麦籽粒灌浆中后期的GBSS活性高低对淀粉总积累量的作用大于前期，进而影响其产量。本试验中，浅埋滴灌W3处理灌浆后期GBSS、SSS酶的活性较高，籽粒淀粉积累量吐丝后55 d较膜下滴灌高13%，这说明浅埋滴灌下GBSS、SSS酶活性对灌浆后期总淀粉积累具有重要作用。

水分胁迫使AGPase、GBSS、SSS酶活性降低[27]，王自布等[49]在小麦研究中发现，水分不足时，提高灌浆前、中期淀粉合成酶活性，显著降低后期淀粉合成酶的活性。黄天琪[50]对玉米研究表明，水分亏缺降低AGPase、GBSS、SSS 3种酶的活性，缩短峰值出现的时间。本研究中，W1处理浅埋滴灌和膜下滴灌均较低，说明W1灌水量未达到充分灌溉，浅埋滴灌低于膜下滴灌主要是由于膜下滴灌覆膜保墒效果较好，土壤水分流失低于浅埋滴灌，水分亏缺程度轻，淀粉合成酶活性较高。W3处理浅埋滴灌AGPase、GBSS、SSS酶活性高于膜下滴灌，课题组前期研究发现，浅埋滴灌下春玉米全生育期最佳灌水量为2 351.18 m3·hm-2[51]，本文中传统灌水量60%（灌量2 160 m3·hm-2）为苗期到收获期灌水量，加上引苗水400 m3·hm-2，全生育期灌水量为2 560 m3·hm-2，达到充分灌溉，且生育后期淀粉合成酶活性较高；膜下滴灌根系分布于浅层土壤较多，马金平等[52]指出，膜下滴灌较浅埋滴灌根系分布浅10 cm，而深层根系对后期抗衰有较大贡献，加之覆膜虽减小了土壤蒸发，但增大了植株蒸腾，增加叶片水分和营养散失，导致膜下滴灌生育后期淀粉合成酶较低。

4 结论

浅埋滴灌优化灌溉可增加粒重进而提高产量，实现节水增效。在传统灌水量60%时（2 160 m3·hm-2），浅埋滴灌下春玉米籽粒灌浆后期淀粉合成相关酶（AGPase、GBSS、SSS酶）活性强、淀粉活跃积累期延长，积累达到最大速率的时间延后，生育后期淀粉积累能力增强，千粒重增加，产量显著提高，可推荐为研究区节水增效适宜滴灌模式。

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Effects of Different Drip Irrigation Modes on Starch Accumulation and Activities of Starch Synthesis-Related Enzyme of Spring Maize Grain in Northeast China

ZHANG JiaHua1, YANG HengShan1, ZHANG YuQin1, LI CongFeng2, ZHANG RuiFu1, TAI JiCheng1, ZHOU YangChen1

1College of Agronomy, Inner Mongolia Minzu University, Tongliao 028000, Inner Mongolia;2Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081

【】The aim of this study was to explore the effects of different drip irrigation modes on starch accumulation and starch synthesis-related enzyme activities of spring maize, so as to provide a physiological basis for the understanding of the yield formation process in maize under the water-saving conditions.【】 Using maize variety Nonghua 101 as the experimental material, a sub-plot design was selected for this experiment, and two irrigation modes were chosen as the main plot, including mulched drip irrigation (MDI) and shallow drip irrigation (SBDI), and the irrigation amount as the sub-plot included three irrigation levels (W1: 1 440 m3·hm-2; W2: 1 800 m3·hm-2; W3: 2 160 m3·hm-2, which equaled to the amount of 40%, 50% and 60% of the traditional irrigation, respectively). The amount and time of drip irrigation was conducted at the ratio of 1﹕2﹕2﹕3﹕2 for seedling stage to jointing stage, jointing stage to big bell mouth, big bell mouth to silking stage, silking stage to milk stage, and milk stage to harvest stage, respectively. The corn kernels were taken at every 7 days from 20 days after silking. The content of total starch in maize kernel was determined by acid hydrolysis DNS method. The starch synthase activity assay kit was used to determine the activity of adenosine diphosphate glucose pyro phosphorylase (ADPase), bound starch synthase (GBSS), and soluble starch synthase (SSS). On basis of that, the maize grain yield, characteristics of starch accumulation, and the changes enzyme activity of ADPase, GBSS and SSS were investigaged.【】There was no significant difference between effective panicle number and grain number per panicle of the two irrigation modes, and the 1000-grain weight and grain yield in shallow drip irrigation was lower than that of mulched drip irrigation under the treatment of W1, but no significant difference were found under the treatment of W2. The grain yield and 1000-grain weight in shallow drip irrigation were 5.7% and 8.4% higher in grain yield, and 11.9% and 12.1% higher in 1000-grain weight than that in mulched drip irrigation under treatment W3 in 2019 and 2020, respectively. The results of variance analysis showed that irrigation amount, drip irrigation mode and the interaction between irrigation amount and drip irrigation mode had a significant effects (＜0.01 or＜0.001) on 1000 grain weight, and the interaction between years, irrigation amount and drip irrigation mode had a significant effects (＜0.01 or＜0.001) on grain yield. Considering the content and accumulation of starch in grain, the shallow drip irrigation were both lower than that of mulched drip irrigation of W1, and W2 was lower than mulched drip irrigation in 20 days after silking, while no significant difference in 55 days after silking; W3 was lower than mulched drip irrigation in 41 days after silking, while higher than in 55 days after silking. Under the three irrigation amounts, the active accumulation period of starch in grain under shallow drip irrigation was longer than that of mulched drip irrigation, and the time for grain starch accumulation to reach the maximum rate was later than that of shallow drip irrigation. Active accumulation period of starch had the highest influence coefficient on the final accumulation of starch, then was the time of maximum rate. The starch accumulation rate in the late growth stage was highly correlated with the total starch accumulation in grains (＜0.001) and the yield (＜0.01). The activity of ADPase, GBSS and SSS in shallow drip irrigation were lower that of mulched drip irrigation in 20-27 d after silking, while the difference was reducing along with the maize growth; The three enzyme activity were higher under W3 than that of mulched drip irrigation at 48 days after silking, and also under W1 and W2 at 55 days after silking. Except no relationship of accumulation rate of grain starch and activity of ADPase under W1, the accumulation rate of grain starch showed a significantly positive relation with the activities of ADPase, GBSS and SSS under other treatments. 【】With the 60% of the traditional irrigation amount in shallow drip irrigation, it showed a higher activity of ADPase, GBSS and SSS at the late filling stage and a longer active starch accumulation period, also enhanced the ability of starch accumulation and increased 1000-grain weight, and possessed the highest maize grain yield. The shallow drip irrigation could increase the activity of the maize starch synthases, enhance the ability of starch accumulation, then increased grain weight and yield, and finally reached the purpose of water-saving and efficiency-improvement.

drip irrigation modes; spring maize; grain; enzyme activity; starch accumulation