海岛棉和陆地棉叶片光合能力的差异及限制因素

研究海岛棉和陆地棉两个栽培种间叶片的光合特性及组织解剖结构特性,揭示不同棉花栽培种叶片的光合能力的差异,探讨如何进一步提高海岛棉的光合物质生产能力,以期为高光效棉花品种选育和高产高效栽培实践提供理论基础。在新疆气候生态条件下,选用北疆棉区有代表性的海岛棉品种新海22号和陆地棉品种新陆早13号为试验材料,分别测定了两棉花栽培种叶片的净光合速率（PN）、气孔导度（Gs）及叶片温度的日变化,PN-PPFD（光量子通量密度）响应曲线,PN-Ci（胞间CO2浓度）响应曲线以及叶绿素含量、叶片面积、比叶重和地上部生物量等指标,并观察了叶片的形态解剖结构特性。研究结果表明,当新陆早13号叶片被固定于水平方向上以后,日进程中新海22号的叶片温度显著高于新陆早13号。在上午和下午光强较低时,新海22号和新陆早13号的PN和Gs无明显差异;12:00h至16:00h（北京时间,下同）,新海22号叶片的PN和Gs均显著低于新陆早13号。新海22号和新陆早13号叶片的PN-Ci响应曲线无明显差异。新海22号叶片的Pmax（最大光合速率）低于新陆早13号,而两者的AQY（表观量子效率）无显著差异。新海22号叶片的栅栏组织厚度、比叶重和生物量均显著低于新陆早13号,而叶绿素含量和叶片面积均显著高于新陆早13号。因此,田间条件下,海岛棉叶片的实际光合能力低于陆地棉,但两者具有相似的光合潜力。气孔导度是导致海岛棉和陆地棉叶片实际光合能力存在差异的重要原因,而栅栏组织较薄限制了海岛棉叶片光合潜力的进一步发挥。     

自然条件下珊瑚树叶片光合作用的光抑制

利用气体交换观察、叶绿素荧光分析和ＱＢ蛋白含量的测定３种方法,研究了常绿灌木珊瑚树叶片的光合作用在上海深秋初冬自然条件下的光抑制。以便确定在除光以外不存在其它环境胁迫的自然条件下光合机构的破坏是否时引起光抑制的主要原因。经过中午３ｈ左右的强光照射以后,珊瑚树叶片的表观量子效率和ＰＳⅡ光化学效率明显下降,表明珊瑚树叶在自然条件下经常发生光抑制。而且,经中午强光照射以后,叶片的初始荧光下降;非光化学荧     

青海高原及上海平原地区植物叶片光合作用的光抑制

用便携式ＡＤＣ光合气体分析系统和便携式ＣＦ－１０００荧光仪对青海和上海的同一植物和不同植物叶片光合作用的光抑制进行了测定。结果表明,两地在晴天强光下,中午植物叶片光系统Ⅱ（ＰＳⅡ）的光化学效率（Ｆｖ／Ｆｍ）和表观光合量子效率（ＡＱＹ）的日变化比早晨低;上海测定ＰＳⅡ的Ｆｖ／Ｆｍ和ＡＱＹ的日变化比青海的下降幅度大。ＡＱＹ的日变化曲线比ＰＳⅡ的Ｆｖ／Ｆｍ低,ＡＱＹ降低的幅度比ＰＳⅡ的Ｆｖ／Ｆｍ大。两地植物均有不同程度的光合作用光抑制,且上海比青海的大     

海岛棉与陆地棉叶绿素含量变化的差异研究

以5份陆地棉和4份海岛棉为材料,研究了整个发育进程中陆地棉和海岛棉叶绿素的变化规律之间的差异,结果显示：陆地棉与海岛棉的叶绿素a、叶绿素b和叶绿素a＋b各有不同动态变化规律,其叶绿素a/b在整个发育进程中的变化也有差异。海岛棉与陆地棉的叶绿素a变化趋势有较大差别,陆地棉的叶绿素a含量在6月18日（苗期）最高,峰值出现在8月6日,海岛棉峰值、最大值均在7月4日（现蕾期）;叶绿素b含量表现为陆地棉、海岛棉峰值均在8月6日（花铃期）,但海岛棉平均值高于陆地棉;陆地棉的叶绿素a＋b和叶绿素a曲线相似,海岛棉的叶绿素a＋b和叶绿素b曲线相似;陆地棉叶绿素a/b值表现苗期最大,然后迅速下降,海岛棉a/b值表现普遍低于陆地棉,其变化趋势为前期在7月4日出现峰值,然后下降再升高。实验说明陆地棉和海岛棉叶绿素的合成机制、调控机理可能不同。     

光强对番茄叶片低温光抑制恢复的影响

经弱光 (6 0 μmol·m- 2 ·s- 1 )和 5℃低温处理 3d的番茄叶片Fv Fm和ΦPSⅡ下降 ,F0 没有变化 ;随后放在弱光 (6 0 μmol·m- 2 ·s- 1 )和 2 5℃条件下 ,番茄叶片的Fv Fm和ΦPSⅡ可以恢复 ,而在强光 (80 0 μmol·m- 2 ·s- 1 )下恢复的植株Fv Fm和ΦPSⅡ则显著下降 ,F0 也明显增加。恢复 3d后 ,弱光下恢复的植株光合作用可恢复到对照水平的 72 .1% ,而强光下恢复的植株光合作用仍维持在很低的水平     

田间条件下棉花幼叶光合特性及光保护机制

通过比较棉花(Gossypium hirsutum)幼叶和完全展开叶气体交换参数及叶绿素荧光特性的差异, 探讨高光强下幼叶的光抑制程度及明确光保护机制间的协调机理。在田间自然条件下, 以棉花刚展平的幼嫩叶片(幼叶)和面积已达到最大的完全展开叶片为研究对象, 通过测定不同发育阶段叶片气体交换参数及叶绿素a荧光参数的变化, 并运用Dual-PAM100对不同发育阶段的叶片进行快速光响应曲线的拟合。结果表明: 幼叶和完全展开叶片在光合、荧光特性方面表现出明显的差异。与完全展开叶相比, 较低的叶绿素(Chl)含量和气孔导度(G_s)是幼叶较低净光合速率(P_n)的限制因素, 从而直接导致其光系统II (PSII)实际光化学效率(Φ_PSII)和光化学猝灭系数(q_P)的降低。在1800 μmol·m^-2·s^-1光强以下, 完全展开叶具有较强的围绕PSI循环的电子流(CEF), 有利于合成ATP, 是其具有较高光合能力的原因之一。相同光强下, 幼叶较低的光饱和点(LSP)更易受光抑制, 但其PSII原初光化学效率(F_v/F_m)的日变化幅度显著小于完全展开叶, 说明强光下幼叶通过类胡萝卜素(Car)猝灭单线态氧、光呼吸(P_r)、热耗散(NPQ)以及PSI-CEF等光保护机制能有效地耗散过剩的光能, 从而避免其光合机构发生光抑制。     

土壤水分亏缺对陆地棉花铃期叶片光化学活性和激发能耗散的影响

 为了探讨水分亏缺对叶片光合机构光化学量子效率和非辐射热耗散的影响,在新疆气候生态条件下,采用膜下滴灌技术精确地控制滴水量,实 现不同程度的土壤水分亏缺,系统测定了不同水分条件下陆地棉（Gossypium hirsutum）叶片叶绿素荧光参数、叶片接受光量子通量密度 （Photon flux density, PFD）、叶片温度（Leaf temperature, T_leaf）以及叶片水势和叶绿素含量的变化。研究表明：轻度水分亏缺（田间 持水量的 55%～60%）叶片接受的PFD与对照（田间持水量的70%～ 75%）无差异,T_leaf略高于对照;中度水分亏缺（田间持水量的40%～45%） 在12∶00 (北京时间,下同)以前叶片接受的PFD和对照无差异,随后显著低于对照,T_leaf在整个日变化中均高于对照。 不同水分处理对 黎明 前叶片PSⅡ最大光化学效率（The maximum photochemical efficiency of PSⅡ, F_v/F_m）没有影响。轻度水分亏缺叶片的实际光化学效率（PS Ⅱ photochemical efficiency,φPSⅡ）、表观电子传递速率（ Electron transport rate, ETR）和光化学猝灭系数（Photochemical quenching,q_p）的日变化与对照基本一致,非光化学猝灭系数（Non-photochemical quenching, NPQ）在12∶00以前和14∶00以后显著低于对 照,在12∶00～14∶00和对照无差异。中度水分亏缺叶片的φPSⅡ、ETR和qp在12∶00才显著降低,此后由于叶片出现暂时萎焉、下垂,所接受 的PFD减弱,叶绿素荧光参数缓慢恢复,且高于对照;NPQ在12∶00 以前显著高于对照,14∶00略高于对照,此后低于对照。水分亏缺导致中午 叶片水势和叶绿素a、叶绿素b含量降低,但叶绿素a/b比值升高。因此,在田间条件下,陆地棉可通过叶片萎焉下垂运动和叶绿素含量的变化调 节叶片对光能的捕获,以及通过光合电子传递、热耗散水平的变化来适应水分亏缺的逆境。在中度水分亏缺条件下,陆地棉叶片萎焉下垂运动 的被动调节减少了过量激发能对光合机构的伤害,保证了光合机构的正常运转。     

田间大豆叶片成长过程中的光合特性及光破坏防御机制

田间大豆叶片在成长进程中光饱和光合速率持续提高,但气孔导度的增加明显滞后.尽管叶片在成长初期就具有较高的最大光化学效率,但是仍略低于发育成熟的叶片.随着叶片的成长,光下叶片光系统Ⅱ实际效率增加;非光化学猝灭下降.幼叶叶黄素总量与叶绿素之比较高,随着叶面积的增加该比值下降,在光下,幼叶的脱环氧化程度较高.因此认为大豆叶片成长初期就能够有效地进行光化学调节;在叶片生长过程中依赖叶黄素循环的热耗散机制迅速建立起来有效抵御强光的破坏.     

环境强光诱导玉簪叶片光抑制的机制

为进一步阐述光抑制的强光诱导和发生机制, 该文以喜阴植物玉簪(Hosta spp.)为材料研究其光抑制发生规律及其与环境光强的关系。结果表明, 全日照和遮阴条件下玉簪叶片发育分别形成适应强光和弱光的形态特征; 与遮阴处理相比, 强光下生长的玉簪光合速率和叶绿素含量较低, 但两种处理叶片最大光化学效率差异很小, 证明强光下植株可以正常生长且光合机构未发生严重的光抑制。将遮阴处生长的植株转移到全日照下, 光合速率和最大光化学效率急剧下降; 荧光诱导动力学曲线发生明显改变, 而且光系统II供体侧和受体侧荧光产量的变化幅度分别达到24.3%和34.2%, 表明玉簪由弱光转入强光后光系统II发生不可逆失活, 且受体侧受到的伤害较供体侧更严重。因此, 作者认为环境光强骤然提高并超过玉簪生长光强时很容易诱导其光合机构发生严重的光抑制。该研究对于理解植物适应光环境的策略以及喜阴植物的优质栽培有重要意义。     

利用海岛棉渐渗系改良陆地棉纤维品质

棉花是世界上种植最广泛的纤维作物,随着人们生活水平的提高和棉纺织工业的发展,对棉花的纤维品质提出了更高的要求.本研究利用渐渗系ZP171为亲本,该材料以陆地棉中棉所8号为遗传背景携带了纤维品质优异的海岛棉Pima90-53片段,构建遗传群体并选育优异种质材料.基于群体在多环境下的纤维品质鉴定结果,发现纤维长度和比强度与...     

Photosynthesis and photoprotection in mangroves under field conditions

Net CO₂ exchange and in vivo chlorophyll fluorescence were studied in mangrove (Rhizophora stylosa) leaves at a field site in Western Australia, and leaf samples were collected for the analysis of enzymes and substrates potentially involved in anti-oxidant photoprotection. Photosynthesis saturated at 900 μmol quanta m^?2 s^?1 and at no more than 7.5 μmol CO₂ m^?2 s^?1. However, fluorescence analysis indicated no chronic photoinhibition: F_v:F_m was 0.8 shortly after sunset, and quantum efficiencies of PSII were high up to 500 μmol quanta m^?2 s^?1. Electron flow through PSII was more than 3 times higher than electron consumption through Calvin cycle activity, however, even with photorespiration and temperature-dependent Rubisco specificities taken into account. Acknowledging the growing body of literature attributing a role to antioxidant systems in photoprotection, we also assayed the activities of superoxide dismutase (SOD) and several enzymes potentially involved in H₂O₂ metabolism. Their levels of maximal potential activity were compared with those in greenhouse-grown mangroves (R. mangle), and growth chamber-grown peas. Monodehydroascorbate reductase activities were similar in all species, and glutathione reductase was lower, and ascorbate peroxidase ～40% higher, in the mangroves. SOD activities in field-grown mangroves were more than 40 times those in peas. Our results support the hypothesis that O₂ may be a significant sink for photochemically derived electrons under field conditions, and suggest an important role for O₂^? scavenging in photoprotection. However, when relative patterns are compared between species, imbalances between SOD and the other enzymes in the mangroves suggest that more components of the system (e.g. phenolics or peroxidases) are yet to be identified.     

A Comparison of Leaf Anatomy in Field-grown Gossypium hirsutum and G. barbadense

Gossypium hirsutum L. (upland cotton) and G. barbadense L. (Pimacotton) are two of the most important fibre producing cottonspecies in cultivation. When grown side-by-side in the field,G.hirsutum has higher photosynthetic and transpiration rates (Luet al., 1997. Australian Journal of Plant Physiology24: 693–700).The present study was undertaken to determine if the differencesin physiology can be explained by leaf and canopy morphologyand anatomy. Scanning electron microscopy was used to comparethe leaf anatomy of field-grown upland (‘Delta’and ‘Pine Land 50’) and Pima (‘S6’)cotton. Compared to G. hirsutum, mature leaves of G. barbadenseare larger and thinner, with a thinner palisade layer. G. barbadenseleaves show significant cupping or curling which allows fora more even absorption of insolation over the course of theday and much more light penetration into the canopy. AlthoughG. barbadense leaves have a 70–78% higher stomatal densityon both the abaxial and the adaxial surfaces, its stomates areonly one third the size of those of G. hirsutum. This resultsin G. barbadense having only about 60% of the stomatal surfacearea per leaf surface area compared to G. hirsutum. These resultsare indicative of the anatomical and physiological differencesthat may limit the yield potential of G. barbadense in certaingrowing environments. Copyright 2000 Annals of Botany Company Cotton, leaf anatomy, leaf development, photosynthesis, Gossypium hirsutum, Gossypium barbadense, stomatal density     

Regeneration of Gossypium hirsutum and G. barbadense from shoot apex tissues for transformation

A method of regenerating cotton plants from the shoot apical meristem of seedlings was developed for use with particle gun and Agrobacterium-mediated transformation. This method was developed to circumvent the problems of genotype restriction and chromosomal damage frequently encountered in cotton regeneration in tissue culture through somatic embryogenesis. In this procedure, the cells of the shoot meristem are targeted for transformation. Normal and fertile plants of Gossypium barbadense Pima S-6, and 19 cultivars of G. hirsutum were regenerated using this method. Shoot regeneration from these tissues was direct and relatively rapid. A MS based, hormone-free medium could be used with all the varieties tested.This project was funded by grants from Cotton Incorporated, Nisshinbo Industries, and a grant from the Texas Agricultural Experiment Station to RHS. Texas Agricultural Experiment Station Technical Article TA-25667.     

苗期遮荫对花生（Arachis hypogaea L.）光合生理特性的影响

大田条件下,以花生品种"花育22号"为材料,齐苗期设置遮荫50%和85%两个遮荫强度分别处理40d,研究了遮荫对花生光合特性的影响及遮荫解除后的光合恢复规律.结果表明:(1)与正常光照条件相比,遮荫花生叶片净光合速率(Pn)、RuBP羧化效率降低,叶绿素含量、表观量子效率及光系统Ⅱ的最大光化学效率(Fv/Fm)增加,表明花生对弱光胁迫有一定的自我调节和适应能力.(2)遮荫和自然光下生长的花生中午强光下的Fv/Fm值均明显下降,表明发生了光抑制,遮荫程度越大,光抑制愈严重.(3)Fv/Fm值和净光合速率Pn遮荫解除后5d之内持续下降,之后逐步恢复.遮荫50%处理的叶片Fv/Fm值和Pn分别于遮荫解除后8d和10d左右恢复到对照水平;遮荫85%的处理分别于遮荫解除后15d和20d左右才恢复到最大,但Pn不能恢复到对照水平,显著低于对照.     

陆地棉遗传图谱构建与纤维品质性状QTL定位

以陆地棉(Gossypium hirsutum L.)品种Bar19/1和Acala1517-77杂交的108个F2单株为材料,应用85个标记(70个SSR标记和15个AFLP标记)构建了总长为814cM的遗传图谱,覆盖棉花基因组的18.3%。该图谱包含25个连锁群,分别对应到17条染色体和4个未知连锁群。应用复合区间作图法分析了该组合的108个F2单株和F3家系纤维品质性状,从遗传图谱上检测到19个纤维品质数量性状基因座(QTL),包括5个纤维长度、6个纤维比强度、4个伸长率及4个马克隆值QTL,分别解释各性状表型变异的15.11%~28.45%、8.46%~24.51%、11.08%~27.55%和9.23%~42.21%。纤维长度和伸长率的QTL以部分显性为主,少数具有超显性,比强度QTL以加性和部分显性为主,4个马克隆值QTL中有3个表现为超显性。研究结果表明,陆地棉Bar19/1和Acala1517-77间多态性位点丰富,有利于构建高密度遗传图谱,纤维品质性状的QTL分析从分子水平上揭示了纤维品质的遗传基础。     

SSR marker-assisted improvement of fiber qualities in Gossypium hirsutum using G. barbadense introgression lines

Key message

This study demonstrates the first practical use of CSILs for the transfer of fiber quality QTLs into Upland cotton cultivars using SSR markers without detrimentally affecting desirable agronomic characteristics.

Abstract

Gossypium hirsutum is characterized by its high lint production and medium fiber quality compared to extra-long staple cotton G. barbadense. Transferring valuable traits or genes from G. barbadense into G. hirsutum is a promising but challenging approach through a traditional interspecific introgression strategy. We developed one set of chromosome segment introgression lines (CSILs), where TM-1, the genetic standard in G. hirsutum, was used as the recipient parent and the long staple cotton G. barbadense cv. Hai7124 was used as the donor parent by molecular marker-assisted selection (MAS). Among them, four CSILs, IL040-A4-1, IL080-D6-1, IL088-A7-3 and IL019-A2-6, found to be associated with superior fiber qualities including fiber length, strength and fineness QTL in Xinjiang were selected and backcrossed, and transferred these QTLs into three commercial Upland cotton cultivars such as Xinluzao (XLZ) 26, 41 and 42 grown in Xinjiang. By backcrossing and self-pollinating twice, five improved lines (3262-4, 3389-2, 3326-3, 3380-4 and 3426-5) were developed by MAS of background and introgressed segments. In diverse field trials, these QTLs consistently and significantly offered additive effects on the target phenotype. Furthermore, we also pyramided two segments from different CSILs (IL080-D6-1 and IL019-A2-6) into cultivar 0768 to accelerate breeding process purposefully with MAS. The improved lines pyramided by these two introgressed segments showed significant additive epistatic effects in four separate field trials. No significant alteration in yield components was observed in these modified lines. In summary, we first report that these CSILs have great potential to improve fiber qualities in Upland cotton MAS breeding programs.