Development and Distribution of Root System in Two GrainSorghum Cultivars Originated from Sudan under Drought Stress

Abstract

The difference in rooting pattern between two grain sorghum cultivars differing in drought tolerance was investigated under drought stress. The cultivars, Gadambalia (drought-tolerant) and Tabat (droughtsusceptible), were grown in bottomless wooden or acrylic root boxes to examine root parameters. Gadambalia consistently exhibited higher dry matter production and leaf water potential than Tabat under drought stress in both root boxes. In the experiment with wooden root boxes, under a drought condition, Gadambalia extracted more water from deep soil layers (1.1-1.5 m), which was estimated from the reduction in soil water content, than Tabat. This was because Gadambalia had a significantly higher root length density in these soil layers. The high root length density was due to enhanced lateral root development in Gadambalia. In the other experiment with acrylic root boxes, though total root length in the upper soil layer (0-0.5 m) was declined by limited irrigation in both cultivars, the reduction in Gadambalia was moderate compared with that in Tabat owing to the maintenance of fine root growth. Unlike Tabat, Gadambalia had an ability to produce the nodal roots from higher internodes even under drought, which resulted in the high nodal root length of Gadambalia. The growth angle of nodal roots was significantly correlated with root diameter, and the nodal roots from the higher internodes had large diameters and penetrated into the soil more vertically. These results indicate that the responses of roots (i.e. branching and/or growth of lateral root, and nodal root emergence from higher internodes) to soil dryness could be associated with the drought tolerance of Gadambalia.     

大豆抗旱种质的鉴定及其与根系的关系

从辽宁省主要推广品种中选出20份优异种质资源,依据株高、叶面积指数、茎、叶生物量为指标,采用平均隶属函数值方法鉴定了大豆苗期耐旱性.结果从供试材料中共筛选出大豆生长前期较强耐旱型(2级)品种2个,干旱较敏感型(4级)品种3个,中间型(3级)品种15个.大豆的平均耐旱隶属函数值与干旱胁迫下的相对根表面积、相对根生物量分别...     

Lodging Resistance Related to Root Traits for Mechanized Wet-Seeding of Two Super Rice Cultivars

Mechanical hill wet-seeded rice machine is beneficial for establishing and growing uniform rows of seedlings.However,there is limited knowledge regarding the effects of the establishment of furrows on growth,lodging and yield,and their relationships with root traits.In this study,field experiments were conducted during 2012 and 2013 using two super rice varieties(hybrid rice Peizataifeng and inbred rice Yuxiangyouzhan)under three furrow establishment treatments(T1,both water and seed furrows were established by the machine;T2,only seed furrows were established by the machine;and T3,neither water nor seed furrows were established by the machine).Lodging index,lodging-related traits,grain yield,above-ground dry weight and root traits were measured.The results showed that the lodging index was significantly affected by the treatments with furrows(T1 and T2).The strongest lodging resistance was detected in the mechanical hill wet-seeded rice with furrow treatment(T1)in both 2012 and 2013.Lodging resistance was strongly related to the breaking resistance.No significant difference was found in grain yield or dry weight of the mechanical hill wet-seeded rice.Therefore,the mechanical hill wet-seeded rice with furrow treatment increased rice lodging resistance,which was related to root traits.     

干旱胁迫对不同抗旱性小麦种子萌发及幼苗根芽生物量分配的影响

为探讨冬小麦种子萌发期抗旱性与幼苗生物量分配的关系,以小麦抗旱型品种长旱58和干旱敏感型品种漯麦18为材料,采用聚乙二醇(PEG-6000)模拟干旱胁迫的方法,测定和分析了干旱胁迫后小麦种子发芽率、幼苗根冠比、叶绿素含量等16个指标的变化。结果表明,干旱胁迫后,长旱58种子发芽率无明显变化,漯麦18种子发芽率显著下降。干旱胁迫下长旱58种子发芽势、发芽指数、活力指数和干物质转移量显著大于漯麦18,平均发芽时间显著小于漯麦18,长旱58幼苗根、芽的长度和干重及总干重均显著高于漯麦18。干旱胁迫显著增加漯麦18幼苗根冠比,对长旱58萌发第五和第七天的幼苗根冠比无显著影响。干旱胁迫显著降低漯麦18幼苗叶绿素含量,对长旱58无显著影响。由于小麦萌发期幼苗干物质累积取决于种子中营养物质的转移和呼吸消耗,因此推测种子营养物质的快速转移和低呼吸消耗有助于提高小麦萌发期的抗旱能力,促进干旱胁迫下种子萌发和幼苗生长。     

海南山栏稻农艺特征与抗旱生理特性研究

研究了１２个山栏稻原始种质的主要农艺性状、品质特征及抗旱生理特性，并与水稻不同类型的对照进行比较分析。结果表明，在旱地栽培条件下，山栏稻的穗长、穗粒数、衙粒重及单株产量均显高于对照水稻．但不时也表现高杆、穗颈过长、移片大且披垂等不良性状。在品质方面，山栏稻糙米粗蛋白含量、１７种氨基酸含量及２种必需氨基酸含量显高于水稻对照。山栏稻种子在高渗溶液中的发芽率、离体叶片保水率、质膜稳定性和分蘖秆长整齐     

冬小麦叶绿素荧光参数与品种抗旱性的关系

为了明确不同生态型小麦品种的光合抗旱特征,选取生态型相异的小麦品种在不同供水条件下种植,测定其旗叶的叶绿素荧光动力学参数,对其在干旱胁迫下的光合特性进行比较研究。结果表明,干旱胁迫使小麦Fo增加,Fm、Fv、Fv/Fm和Fv/Fo值均降低,但变化幅度因生态型而异,高水肥品种的荧光参数对干旱胁迫更为敏感,而旱肥型品种则表现出较强的光合稳定特性。干旱胁迫下,叶绿素荧光参数变化与品种抗旱性密切相关。利用不同生态型小麦品种叶绿素荧光对干旱胁迫的反应差异鉴定品种抗旱性是可行的。     

干旱胁迫下玉米杂交组合抗旱性及水分利用的研究

By pot experiments under an anti-drought and rain-proof shelter,two water treatments were designed including normal water supply and middle drought stress.It was studied to biological output,drought resistance,water consumption and water use efficiency(WUE) of 10 maize hybridized combinations.The results showed that there was significant difference or extreme significant difference in biological output and drought resistance and water consumption and water use efficiency(WUE) of 10 maize hybridized combinations under different soil moisture treatments.Comprehensive analysis on biological output and drought resistance and water consumption and water use efficiency(WUE),the performance of cross51×18599 was the best,and it was hybridized combination with high yield,drought resistance well,medium water consumption and high water use efficiency(WUE).     

干旱胁迫下氮素对不同基因型小麦根系活力和生长的调控

为了探讨不同水氮耦合处理对小麦根系活力和吸收氮素能力的影响,以多穗型小麦品种西农979和大穗型小麦品系2036为材料进行营养液培养试验,设置正常水分供应、轻度和重度水分胁迫及低氮、中氮和高氮处理,研究了不同水氮耦合对小麦根系形态、根系吸收面积、根系活力、植株氮素积累量的影响。结果表明,水分与氮素存在着明显的互作效应,重度水分胁迫和低氮处理都会降低小麦的生物量、根系总吸收面积、活跃吸收面积和活力、氮含量和植株的氮素积累量,低氮处理增加了根长和根冠比。高氮处理的西农979根系总吸收面积、活跃吸收面积和活力较低,中氮处理显著提高,且分别比2036高11%、14%、27%。西农979在中氮和高氮处理之间的氮素积累量无显著性差异。中氮处理下西农979的植株氮素积累量比2036高13%~62%。相关分析表明,小麦的活跃吸收面积、根系活力与植株氮素积累量呈极显著正相关(P0.01),和根冠比呈极显著负相关(P0.01)。在轻度水分胁迫下,增加氮素供给能有效提高西农979的根系吸收面积和根系活力;过高的氮素不利于2036根系的生长,表明不同基因型小麦的根系活力和生长对不同水氮耦合的响应不同。通过适宜的水氮耦合调控,有利于创造良好的小麦根系形态,提高根系活力及对水分和养分的吸收能力。     

干旱处理对不同品种茶树生理特性影响及抗旱性综合评价

以龙井43、槠叶齐、宁州2号和白叶1号两年生盆栽扦插茶苗为试验材料进行自然干旱处理,测定其在干旱胁迫及复水下的生长适应规律,探讨干旱处理对不同品种茶树叶片生理特性的影响,并利用隶属函数值法对这4个品种耐旱性进行综合评价。结果表明,随着干旱处理时间延长,4个品种土壤体积含水量逐渐降低,植株表现脱水症状,叶片相对含水量逐渐降低,MDA含量逐渐升高,SOD活性逐渐降低,POD和CAT活性呈先升后降趋势,净光合速率和蒸腾速率逐渐降低,水分利用效率呈先升后降趋势,叶绿素和类胡萝卜素总量逐渐升高。复水后,4个品种土壤体积含水量和叶片相对含水量升高,MDA含量降低,龙井43 POD活性升高,其他品种均降低,SOD活性变化趋势与POD相反,4个品种CAT活性均降低,净光合速率均无显著变化,蒸腾速率和水分利用效率均升高,除槠叶齐叶绿素和类胡萝卜素总量升高外,其他均降低。通过模糊隶属函数值法综合评价该4个品种抗旱性,结果表明,耐旱性强弱依次为龙井43>宁州2号>槠叶齐>白叶1号。本研究为抗旱茶树品种的筛选以及抗旱育种提供参考及理论依据。     

水分胁迫对水稻产量和食味品质抗旱系数的影响

 选用上育397和绥粳3号两个水稻品种，于分蘖期、穗分化期、抽穗后1~10 d、抽穗后11~20 d、抽穗后21~30 d、抽穗后1~30 d分别进行土壤水势为-30~-35 kPa和-60~-65 kPa的控水处理，两品种的产量抗旱系数为穗分化期<分蘖期<抽穗后1~10 d处理，其他时期差异不大。 两品种的食味品质抗旱系数均以穗分化期最低，其他时期差异不大。 穗分化期不仅是产量的水分敏感期，也是食味品质的水分敏感期。 食味的抗旱系数大于产量的抗旱系数，尤其是抽穗前和抽穗后1~10 d 的处理，表明控水对产量的影响大于对食味品质的影响，节水栽培中要充分注意对产量的影响。     

玉米抗旱性研究的现状及展望

本文从玉米的生长发育状况、生物膜结构、激素调节、干旱诱导蛋白等方面综述了干旱胁迫对玉米的伤害及玉米抗旱性的生物学机理,简要介绍了当今玉米抗旱性研究的动向。     

野生二粒小麦根中干旱响应蛋白的分离与鉴定

为了解野生二粒小麦响应干旱胁迫的调控机制,分析了干旱胁迫下小麦根的相对含水量、丙二醛、脯氨酸和过氧化氢含量,采用双向电泳(2-DE)结合MALDI-TOF-TOF-MS方法分离和鉴定了野生二粒小麦根中干旱响应蛋白的变化。结果表明,随着干旱处理时间的延长,野生二粒小麦根的相对含水量下降,脯氨酸含量先上升后降低,过氧化氢含量和丙二醛含量上升;复水后的野生二粒小麦根的相对含水量、脯氨酸含量有所升高,但未达到对照的水平。通过对干旱处理6d后根系的总蛋白进行双向电泳分离和MALDI-TOFTOF生物质谱鉴定,成功鉴定出26个差异表达蛋白,13个上调表达,13个下调表达。26个差异表达蛋白的功能主要涉及信号传导、氧化解毒、碳代谢、能量代谢、蛋白质生物合成及细胞骨架稳定。推测野生二粒小麦为适应干旱胁迫,通过根部感应胁迫信号,并传导至细胞内,影响小麦根中蛋白质的生物合成、氨基酸代谢、碳水化合物代谢、细胞骨架形成;通过抗氧化酶系统和抗氧化物质的作用,将过多活性氧加以清除;通过增加胞内脯氨酸含量,降低根中水分损失。     

干旱胁迫下杂草稻和栽培稻根系基因表达差异研究

利用Affymetrix水稻表达谱芯片(GeneChip Rice Genome Array)研究抗旱杂草稻HEB07-2与巴西陆稻(IAPAR9)在PEG模拟干旱胁迫下根系基因表达变化。结果表明,杂草稻HEB07-2转录组对干旱信号的响应程度与方向均与巴西陆稻存在很大差异,HEB07-2以正向调控为主,而巴西陆稻以负调控为主。干旱胁迫下杂草稻HEB07-2与巴西陆稻分别有6878个和2923个基因表达,其中HEB07-2受干旱胁迫诱导上调的基因有4693个,下调的基因有2185个;而巴西陆稻则分别有983个和1940个。在差异基因表达的倍数上也是HEB07-2高于巴西陆稻。进一步的GO分析表明,在干旱胁迫下,HEB07-2和IAPAR9根系基因响应途径的差异表现为HEB07-2在钾离子转运(GO:0006813)、次生物质代谢(GO:0019748)、细胞生长(GO:0016049)、葡萄糖代谢(GO:0006006)、跨膜离子转运器活性(GO:0015075)、亚铁血红素结合体(GO:0020037)、氧化还原酶活性(GO:0016491)等方面基因显著上调,这与生理数据和表型数据一致。     

甜菜抗旱性评价体系及抗旱育种研究进展

综述了植物抗旱性评价体系研究进展及甜菜抗旱育种方面的研究进展,为建立甜菜抗旱鉴定评价体系,筛选抗旱型甜菜品种提供参考;密切关注这方面的研究进展,有助于甜菜抗旱节水育种方面的研究,提高甜菜对气候变暖、干旱加剧的适应能力。     

Improvement of Upland Rice Variety by Pyramiding Drought Tolerance QTL with Two Major Blast Resistance Genes for Sustainable Rice Production

Varalu is an early maturing rice variety widely grown in the rainfed ecosystem preferred for its grain type and cooking quality. However, the yield of Varalu is substantially low since it is being affected by reproductive drought stress along with the blast disease. The genetic improvement of Varalu was done by introgressing a major yield QTL, qDTY_12.1, along with two major blast resistance genes i.e. Pi54 and Pi1 through marker-assisted backcross breeding. Both traits were transferred till BC₂ generation and intercrossing was followed to pyramid the two traits. Stringent foreground selection was carried out using linked markers as well as peak markers (RM28099, RM28130, RM511 and RM28163) for the targeted QTL (qDTY_12.1), RM206 for Pi54 and RM224 for Pi1. Extensive background selection was done using genome-wide SSR markers. Six best lines (MSM-36, MSM-49, MSM-53, MSM-57, MSM-60 and MSM-63) having qDTY_12.1 and two blast resistance genes in homozygous condition with recurrent parent genome of 95.0%-96.5% having minimal linkage drag of about 0.1 to 0.7 Mb were identified. These lines showed yield advantage under drought stress as well as irrigated conditions. MSM-36 showed better performance in the national coordinated trials conducted across India, which indicated that improved lines of Varalu expected to replace Varalu and may have an important role in sustaining rice production. The present study demonstrated the successful marker-assisted pyramiding strategy for introgression of genes/QTLs conferring biotic stress resistance and yield under abiotic stress in rice.     

水分胁迫对荔枝叶片糖代谢的影响及其与抗旱性的关系

以适应山地栽培的抗旱性较强的东刘1号和适应河边栽培的抗旱性较弱的陈紫1～2年生盆栽实生幼苗为材料,研究了水分胁迫对荔枝叶片糖代谢的影响。结果表明,水分胁迫下,荔枝叶片淀粉酶、转化酶和PAL活性加强,可溶性糖和还原糖含量增加,淀粉和蔗糖含量下降。抗旱性强的品种淀粉酶、转化酶和PAL活性增强的幅度,以及淀粉和蔗糖含量下降的幅度均大于抗旱性弱的品种。     

甘薯植株形态、生长势和产量与品种抗旱性的关系

对水分胁迫下甘薯（IpomoceabatatasLam.）植株形态、生长势和产量性状等指标与品种抗旱性关系的研究结果表明,水分胁迫下不同甘薯品种叶片厚度（包括栅栏组织、海绵组织的厚度及叶片总厚度）、藤叶和块根烘干率比对照均有所增加,叶片大小、叶面积指数（LAD、比叶面积SLA）、主蔓长、主蔓粗、节间长、藤叶和块根重量（鲜、干重）均不同程度减小。栅栏组织厚度、经济系数LAI、分枝数、块根干重及块根烘干率的相对值（占对照%）与品种抗旱性呈显著或极显著正相关（=0.5566～0.9352∶P<0.05,0.01）,主蔓长、节间长及SLA的相对值与品种抗旱性呈显著或极显著负相关（r=-0.5289～-0.737;P<0.05,0.01）,带有直立或缠绕性株型的比纯粹匍匐型品种的抗旱性强。     

水稻生理特性与抗旱性的相关分析及QTL定位

利用籼稻品种IR64和粳稻品种Azucena杂交产生的包含110个加倍单倍体株系的群体,在干旱胁迫和正常水分条件下,连续在2004年和2005年于抽穗期分别测定了叶片水势、相对含水量、叶绿素含量(SPAD值)、游离脯氨酸含量、气孔导度和蒸腾速率,并于成熟期取样,计算抗旱系数。与正常水分状况下相比,干旱胁迫条件下叶片的游离脯氨酸含量的增加达极显著水平,干旱胁迫条件下叶片的相对含水量、水势、叶绿素含量和气孔导度的降低均达显著或极显著水平。相关分析表明,在干旱胁迫条件下,叶片相对含水量、叶片水势与抗旱系数呈显著或极显著正相关。 利用175个RFLP标记构建的遗传连锁图谱分析了与抗旱性相关的叶片生理指标,共检测到与抗旱性相关的6个生理指标的7个加性QTL,31对上位性QTL,其中有2个主效QTL、9对上位性QTL存在环境互作效应。在两种水分条件下检测到的QTL结果有较大差异,说明干旱胁迫对控制与抗旱性相关的叶片生理性状基因的表达有显著的影响。在6个抗旱相关生理指标中,检测到的控制叶片气孔导度和水势的QTL较多,有3个加性QTL和8对上位性QTL控制气孔导度,有8对上位性QTL控制水势。     

冬小麦不同抗旱品种抽穗期干旱诱导蛋白差异与抗旱性的研究

为了确定抗旱小麦新品种的分子鉴定指标,选用5个不同小麦生态类型区共18个新品种,采取盆栽与人工干旱胁迫及SDS-PAGE等方法,研究了抽穗期干旱胁迫诱导蛋白差异与抗旱性的关系。结果表明,根据抗旱指数和反复干旱存活率可将参试品种(系)分为高抗、中抗和低抗3种抗旱类型。提取旗叶蛋白质进行SDS-PAGE分析,发现在水分胁迫条件下一些高分子量的蛋白降解成一些小分子量的蛋白和多肽,其中分子量为66．2kD左右的D-差异蛋白在高抗、中抗旱品种(系)中均有出现,故D-差异蛋白可以作为抗旱小麦新品种筛选和鉴定的分子指标。     

Association and Heritability Studies for Drought Resistance under Varied Moisture Stress Regimes in Backcross Inbred Population of RiceAssociation and Heritability Studies for Drought Resistance under Varied Moisture Stress Regimes in Backcross Inbred Population of Rice

Drought stress is one of the major constraints affecting rice production and yield stability in the rainfed regions. To understand the physiological basis of drought resistance related component traits, we used a backcross inbred population of rice under three kinds of moisture regimes viz., non-stress, moderate （24.48%） and severe stress （73.97%） conditions which reflect the differential responses of the genotypes to varying stress intensities. The plot yield, 1000-grain weight, panicle exsertion and canopy air temperature difference exhibited high heritability under the control conditions, whereas spikelet sterility and single plant yield exhibited high heritability under the moderate stress conditions. Traits such as days to 50% flowering, plant height and osmotic potential showed high heritability under the severe stress conditions. Plot yield under stress was significantly and positively correlated with harvest index and 1000-grain weight, but negatively associated with leaf rolling score and days to 50% flowering. The drought susceptibility index and drought response index were negatively correlated between each other both under the moderate and severe stress conditions. The derived traits viz., difference in panicle length between the control and the severe stress was associated with osmotic adjustment measured under field conditions. Difference in plant height and panicle length was negatively associated with plot yield under stress.