芝麻对涝害的反应及适应性变异Ⅱ. 模拟涝害胁迫下芝麻基因型间的光合生理变化及其对生长调节剂的反应

采用双因素裂区设计 ,研究了 6种芝麻基因型在淹水与非淹水下光合生理指数的相对变化及对生长调节剂的反应。结果表明 ,淹水下 ,净光合速率 ( Pn)、叶绿素含量 ( Chl)显著降低 ,蒸腾速率与气孔阻力无明显差异。基因型间 Pn下降幅度差异大 ,相对值为 0 .65～ 0 .88,以耐渍品种野芝 7号最大 ,非耐渍品种遂平小籽黄最小 ,与相对产量相关系数为 0 .90 91 ,达到显著水平 ,Pn可以作为芝麻耐渍性的生理指标。而 Chl含量下降差异较小 ,相对值为 0 .4 8～ 0 .64 ,以耐渍品种较高 ,与相对产量相关不显著 ,其相关系数为 0 .3 50 2。 3种生长调节剂处理 ,均可使 Pn和 Chl明显提高     

冬小麦不同冠层叶片光合蒸腾和水分利用效率变化特征及对灌溉的响应

为了解冬小麦不同冠层叶片光合和蒸腾作用特征以及随水分条件的变化规律,通过田间试验,以冬小麦京冬22为试验材料,设置0 mm（T₀）、220 mm（T₁）、280 mm（T₂）3种水分处理,比较分析了冬小麦不同冠层叶片净光合速率、蒸腾速率及水分利用效率对光合有效辐射和灌溉响应的差异。结果表明,三种水分处理下,冬小麦不同冠层叶片的蒸腾速率和光合速率随光合有效辐射的增加而增加,随后趋于平缓。不同冠层叶片蒸腾速率、光合速率对光合有效辐射的响应表现为上层>中层>下层;不同冠层叶片WUE对光合有效辐射的响应表现为上中层>下层。光合有效辐射相同时,灌水处理（T₁和T₂）的叶片光合蒸腾速率均高于不灌水处理（T₀）。T₁、T₂处理下,叶片光合速率对光合有效辐射响应在整个生育期内表现为灌浆期>抽穗期>成熟期>拔节期,蒸腾速率对光合有效辐射响应在整个生育期内表现为抽穗期>灌浆期>拔节期>成熟期;T₀处理下,叶片光合速率对光合有效辐射响应在整个生育期内表现为灌浆期>拔节期>抽穗期>成熟期,蒸腾速率对光合有效辐射响应在冬小麦整个生育期内表现不显著。因此,在进行小麦叶片到单株光合蒸腾尺度拓展估算时,应考虑冠层位置和水分条件对拓展结果的影响。     

水分胁迫对不同抗旱性燕麦品种光合及产量形成的影响

为了解水分胁迫对不同抗旱性燕麦品种光合和产量的影响,以抗旱性不同的蒙燕1号和坝莜3号为材料,在拔节期和抽穗期采用防雨棚盆栽方式,测定分析了不同水分处理［重度胁迫（30%田间持水量（FWC））、中度胁迫（45%FWC）,适度控水（60%FWC）和正常供水（CK,75%FWC）］下燕麦叶片叶绿素含量、气体交换速率、叶绿素荧光动力学参数、产量及其构成因素的差异。结果表明,两个燕麦品种叶片叶绿素a含量、叶绿素b含量及叶绿素总含量、净光合速率、蒸腾速率、最大荧光、最大光化学效率（F_v/F_m）、实际光化学效率、光化学猝灭系数均随着水分胁迫程度的加剧而下降,初始荧光与非光化学淬灭系数则呈上升趋势,且水分敏感品种坝莜3号的光合受抑制程度显著大于抗旱品种蒙燕1号。燕麦的光合特性和产量受水分胁迫影响的程度整体上表现为拔节期大于抽穗期。中度和重度水分胁迫下坝莜3号的每穗小穗数、千粒重均下降,而每穗秕粒数显著增加,减产13.9%～25.7%。蒙燕1号的产量在适度控水条件下未显著下降,且水分利用效率较高,而在中度和重度水分胁迫下每穗小穗数和穗粒数均显著降低,导致减产9.1%～23.5%,但其 F_v/F_m和叶绿素a/b值较高;在相同水分条件下蒙燕1号的产量显著高于坝莜3号。这说明在水分胁迫下抗旱性强的燕麦品种的光系统Ⅱ的损伤和光抑制较轻,光合同化能力较强,产量损失少。     

水分胁迫对玉米光合作用的影响

本文综述了水分胁迫对玉米光合作用的影响,并提出了自己的见解.     

Water submersion of seeds from three bean cultivars

Tropical areas exhibit torrential rains, and when the rate of soil drainage is slower than the rate of precipitation, rapid flooding can result which can lead to germination failure. The objective of this study was to evaluate the tolerance of three bean cultivars (IPR-139, Pérola and IPR-Tiziu) to submersion in water for different time periods (0, 1, 2, 4, 8 and 16 h). Seeds were evaluated for moisture content, electrical conductivity, leached ethanol, germination percentage and vigour classification, length and dry weight of roots and shoots, proline content and superoxide dismutase (SOD) activity (an antioxidant enzyme). Increasing the submersion time resulted in decreased germination, vigour and growth, with increased electrical conductivity and leaching of ethanol. Just 1 h of submersion was enough for early differences to be evident among cultivars. The SOD activity was near constant during submersion in all cultivars. Overall, IPR-139 was the most susceptible to submersion, and IPR-Tiziu was the most tolerant cultivar. The tolerance of IRP-Tiziu was related to the high proline content in dry seeds and proline consumption during the submersion period.     

Maize drought tolerance: Potential improvements through arbuscular mycorrhizal symbiosis?

Due to long-term trends in global climate change and the expansion of maize production in drought-prone regions, the development of drought-tolerant maize varieties is of high importance, particularly for maize producers in developing nations where plant breeding improvements are more easily adopted than high-input agronomic practices. Prior advances in breeding for drought-tolerant maize have often involved selection for beneficial morpho-physiological traits such as a reduced anthesis-silking interval (ASI) and an improved harvest index (HI). Although maize is an effective host of arbuscular mycorrhizae (AM) in infertile and drought conditions, few maize breeding and physiological research programs have examined the potential of AM symbiosis to improve maize drought tolerance. The objective of this review is to highlight the morpho-physiological responses and potential mechanisms through which AM colonization might improve maize drought tolerance and, in doing so, to examine the potential of this symbiotic relationship to serve as an effective tool for improving cultivar drought tolerance. In this review, we briefly describe the general effects of AM symbiosis on plant water relations, and then extensively examine the effects of AM colonization on pre-flowering, flowering, and post-flowering maize morpho-physiology under drought-stress conditions in greenhouse and field settings. We then suggest potential areas for future research related to (a) the adoption of cropping practices promoting AM colonization and survival; (b) the further understanding of AM effects on maize morpho-physiology; and (c) the creation of AM-colonized, drought-tolerant maize cultivars through conventional breeding as well as molecular and genomic techniques. We conclude by discussing practical considerations associated with the use of AM for maize drought-stress research and large-scale, commercial maize production.     

叶绿素荧光测定技术在麦类作物耐盐性鉴定中的应用

在介绍叶绿素荧光诱导动力学原理的基础上,综述了叶绿素荧光测定技术在麦类作物耐盐性鉴定上应用的有关研究结果。通过分析叶绿素荧光参数与发芽率、产量等农艺指标及脯氨酸、细胞膜稳定性等生理指标的相关关系,指出叶绿素荧光参数可以作为麦类作物耐盐品种筛选的指标,并就该技术的优点及其实际应用中应注意的问题进行了讨论。     

玉米遮荫胁迫研究进展

遮荫是对玉米生长期间持续阴天寡照的一种模拟,可明显改变玉米的生长环境,限制营养器官和生殖器官发育。遮荫造成叶片出生速度延缓,比叶面积增加,光合性能变差,光合生产能力降低,使雌穗数目减少,雄花退化,雌雄间隔期拉长,结实性下降甚至出现空株。根据近年来国内外玉米遮荫的研究成果,分析遮荫胁迫对玉米形态、生长发育、光合作用、生理特性及产量的影响,探讨玉米遮荫研究方面存在的问题及今后的研究方向。     

Operation of the Ba Lai irrigation system in the Mekong Delta, Vietnam

Ba Lai Irrigation Project is located at coastal area in the Mekong Delta. In dry season when the flow rate decreases and the strong east wind blows into the delta, the salinity intrusion increases and seriously affects agricultural and domestic water use. Intakes of Ba Lai system have to be closed for 1–3 months depending on their locations, and no water supply during this period often causes water pollution in the project area. In order to solve such problems, this study aims to seek gate operation procedures for salinity control and water environment improvement. A numerical model is developed to simulate water movement, salinity concentration and duration of remaining water (water age) within the system under three scenarios: (1) without control structures, (2) with available control structures, (3) with the full control structures. Through the numerical simulations, control structures are confirmed to be an effective measure for the salinity control and suitable gate operation schedules are proposed to improve the water environment in the project.     

前期控水条件下冬小麦的根系和群体光合作用特点

于1991－1994年应用盆栽和大田试验研究了前期控水节水高产技术对冬小麦根系和群体光合作用的调控作用。研究表明,前期限制供水有利前期根系发育,有利产量形成阶段光合物质生产,从而达到节水高产。     

茶树工厂化育苗适宜基质水分条件研究

研究了在不同含水率基质下培养的茶树扦插苗的生长参数、光合作用和叶绿素含量。结果表明:茶苗的新生物量在基质含水率80%~100%时最大,叶面积比(LAR)、比叶面积(SLA)、生根率及比根长(SRL)随基质含水率的增加而增加,根生物量比(RMR)随基质含水率的增加而降低;最大光合速率(Pnmax)随基质含水率的增加而降低,在70%~100%水处理时最大;叶绿素的含量基本上随基质含水率的增加而增加,而叶绿素a/b的值则随基质含水率的增加而降低。因此,在出根后的育苗期间适当降低基质含水率有利于幼苗的形态建成和提高茶苗的光合能力。     

Variation of Salinity Tolerance in zoysia Clones Collected from Different Habitats in Taiwan

Abstract

One hundred and fifteen clones of zoysia spp. collected around the coast of Taiwan were examined for the variation of salinity tolerance. zoysia spp., native of Taiwan, showed a wide range of salinity tolerance among the clones collected from various regions. The clones from the regions with higher annual rainfall and limestone showed lower NaCl tolerance, and some of them showed 100% shoot mortality under 3% NaCl within 3 weeks. On the contrary, some clones from the regions with lower rainfall retained a few green leaves even at 7.5% NaCl for 3 weeks. A positive correlation was observed between the percentages of 100% shoot mortality in clones treated with 6% NaCl and the rainfall of the regions where the clones were collected. However, based on the same level of rainfall, the clones collected from the limestone region showed higher percentages of shoot mortality than those collected from the other regions. Using four clones including NaCl-tolerant and NaCl-sensitive, the effect of Ca on the salinity stress was further examined. Addition of CaCl2 to the nutrient solution could alleviate the leaf firing and electrolyte leakage from the leaf of Zoysia clones caused by NaCl. The geographical variation of salinity tolerance in zoysia might be caused by the differences in the salt and calcium concentrations in soil, which were affected by rainfall and geology of their habitats.     

不同小麦品种（系）对盐碱胁迫的生理及农艺性状反应

对１３份小麦品种（系）在盐碱地进行田间耐盐性鉴定,研究了不同品种光合生理及农艺性状对土壤盐碱胁迫的反应。结果表明,不同品种对土壤盐碱胁迫的反应不同;不同品种、不同时期叶绿素含量及叶绿素荧光值在盐碱胁迫下都有一定的下降。不同农艺性状对盐碱胁迫的反应也不相同,受胁迫的程度依次为产量＞单位面积穗数＞株高＞千粒重＞单穗粒数＞穗长;在盐碱地上产量受限制的主要因素是单位面积穗数和千粒重等。以苗期作为小麦耐盐鉴     

OsSUV3 transgenic rice maintains higher endogenous levels of plant hormones that mitigates adverse effects of salinity and sustains crop productivity

Background

The SUV3 (suppressor of Var 3) gene encodes a DNA and RNA helicase, which is localized in the mitochondria. Plant SUV3 has not yet been characterized in detail. However, the Arabidopsis ortholog of SUV3 (AT4G14790) has been shown to be involved in embryo sac development. Previously, we have reported that rice SUV3 functions as DNA and RNA helicase and provides salinity stress tolerance by maintaining photosynthesis and antioxidant machinery. Here, we report further analysis of the transgenic OsSUV3 rice plants under salt stress.

Findings

The transgenic OsSUV3 overexpressing rice T₁ lines showed significantly higher endogenous content of plant hormones viz., gibberellic acid (GA₃), zeatin (Z) and indole-3-acetic acid (IAA) in leaf, stem and root as compared to wild-type (WT), vector control (VC) and antisense (AS) plants under salt (200 mM NaCl) stress condition. A similar trend of endogenous plant hormones profile was also reflected in the T₂ generation of OsSUV3 transgenic rice under defined parameters and stress condition.

Conclusions

In response to stress, OsSUV3 rice plants maintained plant hormone levels that regulate the expression of several stress-induced genes and reduce adverse effects of salt on plant growth and development and therefore sustains crop productivity.     

调亏灌溉对冬小麦不同生育阶段光合速率的影响

为给冬小麦调亏灌溉（Regulated deficit irrigation,RDI）指标与模式的建立提供理论依据和技术参数,在防雨棚条件下,采用子、母盆栽方法,以冬小麦为试验材料,分析了RDI对冬小麦不同生育阶段光合速率（Pn）的影响,并对其进行了模拟,以探寻适宜的水分调亏阶段（时期）和调节亏水度。结果表明,冬小麦返青至拔节期水分调亏对Pn无显著影响;拔节至抽穗期轻度水分调亏的Pn未受显著影响,复水后补偿效应显著;中、重度调亏的Pn受到显著抑制,复水后虽有补偿效应,但与对照差异不显著;抽穗至灌浆期轻度水分调亏对Pn无显著影响,中、重度水分调亏的Pn受到强烈抑制,复水后补偿效应较弱,补偿时间也有限。据此认为,冬小麦RDI的适宜阶段为拔节期以前,适宜的调亏度为50%～65%FC（Field capacity,FC）;拔节至抽穗和抽穗至灌浆期也可轻度调亏,调亏度为60%～65%FC。     

大豆叶片光合、蒸腾等生理特性的品种间比较研究

在25个大豆品种的鼓粒期,测定了植株主茎自上而下数第3片已完全展开叶的光合速率、暗呼吸速率、蒸腾速率、叶片对水分扩散导性、叶片对CO_2扩散导性、比叶重、叶绿素含量及水分利用效率。结果表明:所测性状在供试品种间均存在着极显著的差异性。在表型、遗传及环境相关分析的基础上,对有关性状间作偏相关分析的结果指出,椭园叶型品种的暗呼吸速率及叶CO_2扩散导性与其光合速率呈极显著偏正相关,并比叶重及叶水分扩散导性与其蒸腾速率呈显著或极显著偏正相关;披针叶型品种的比叶重、叶绿素含量及叶CO_2扩散导性均与其光合速率呈显著或极显著偏正相关,而且比叶重与其蒸腾强度的偏相关也达极显著水平。此外,在两种叶型品种中,光合速率均与蒸腾速率和水分利用效率呈极显著偏正相关,但蒸腾速率则与水分利用效率呈极显著偏负相关。本文还对大豆高光效生理育种及抗旱育种的目标进行了讨论。     

The Role of Active and Passive Water Uptake in Maintaining Leaf Water Status and Photosynthesis in Tomato under Water Deficit

Abstract

Tomato (Lycopersicon esculentum Mill. cv. Know-You 301) shoots were grafted onto the rootstock of the same species or Solanum mammosum and grown in nutrient solution. After the grafted tomato plants developed 4–5 leaves, the uppermost fully expanded leaves were used to determine net photosynthetic rate (P_N) , transpiration rate and leaf water potential (Ψ_L) under control (unstressed) and —0.5 MPa water deficit (mannitol was added to nutrient solution). Both PN and leaf conductance (G_L) were reduced under water deficit. However, tomato plants grafted onto S. mammosum rootstock had higher Ψ_L, P_N and G_L than those grafted onto tomato rootstock under water deficit. This result demonstrates that S. mammosum roots had a greater ability in water uptake under water deficit. Under +0.2 MPa pressure, the root of S. mammosum showed a higher exudation rate than that of tomato. However, the former showed a lower exudation rate than the latter under –0.5 MPa water deficit. It was concluded that the greater ability of water uptake in S. mammosum rootstock under water deficit is related to a lower hydraulic conductivity, which promotes passive, rather than active water uptake.     

棉花喷施光合作用增效剂对其生长发育的影响

通过在南疆主产棉县阿瓦提县进行棉花喷施不同量的“叶之缘”牌植物光合作用增效剂试验,结果表明：在叶绿素含量上看,不同喷施时期以苗期喷施效果较好,盛蕾期次之,而苗期及蕾期各喷施一次效果最差;在花期不同喷施方法中,以喷施900g／hm^2效果最好,其次为450g／hm^2,喷施时应分;次均匀喷施,间隔时间为10天,单次喷施量不应大于450g／hm^2,不同喷施时期及喷施量对单株铃数影响较大,但差异不显著;对子棉产量、单铃重、衣分、纤维品质均无影响。     

半野生和栽培大豆叶片某些光合特性的比较

对半野生、半栽培及栽培大豆叶片某些光合特性指标的比较研究表明,半野生大豆、半栽培大豆和栽培大豆叶面积指数依次降低,而比叶重、叶绿素含量和净光合速率均表现为随品种的进化而增加;从生育期的变化来看,3种类型大豆叶片比叶重和叶绿素含量变化基本一致,苗期和结荚期较低,开花期较高,最大值出现在鼓粒期;3种类型大豆的光合日变化都呈“双峰”曲线型变化,但以栽培大豆日变化最为明显。     

部分CIMMYT小麦种质的耐盐性鉴定与评价

为了筛选耐盐小麦新种质,以耐盐小麦品种青麦6号为对照,分别在小麦苗期以相对盐害指数、芽期以根系盐害易感指数和相对苗长为鉴定和评价指标,对选自国际玉米小麦改良中心（CIMMYT）的417份小麦材料进行耐盐性筛选与鉴定。结果显示,有39份小麦种质的耐盐性优于对照,经相关分析和主成分分析发现,总根长SSI值可作为根系耐盐指标用于耐盐性综合评价;结合总根长SSI值、盐害指数和相对苗长的隶属函数综合值进行聚类分析发现,cm58、cm163、cm439和cm440 四份小麦种质的耐盐性优于对照青麦6号,是研究小麦耐盐性和培育耐盐小麦新品种的优异材料。