棉铃发育期棉花源库活性对棉铃对位叶氮浓度的响应

采用大田试验,以3个铃期差异明显的棉花品种为材料,研究了不同施氮量形成的棉铃对位叶氮浓度对棉花花铃期纤维发育源库活性指标的影响。结果表明:在花后同一时期,棉铃对位叶可溶性糖、蔗糖含量和磷酸蔗糖合成酶活性以及棉纤维蔗糖含量和蔗糖合成酶活性等均随对位叶氮浓度的升高呈先升高后降低的变化趋势(45、52 DPA(花后天数Days post anthesis)的纤维蔗糖含量趋势相反),可用抛物线方程Y=ax2+bx+c拟合(P<0.01),通过拟合方程得到各指标所对应的最佳对位叶氮浓度。45 DPA(德夏棉1号38 DPA)前,花后同一时期各指标对应的最佳对位叶氮浓度差异较小,通过幂函数方程建立最佳叶氮浓度随花后天数的拟合方程,得到纤维发育期内源库活性各指标达到或接近最优状态时的适宜对位叶氮浓度的动态方程。本试验条件下,德夏棉1号、科棉1号和美棉33B的适宜对位叶氮浓度的拟合方程分别为N德1=7.2263DPA-0.276(R2=0.9805**)、N科1=7.23DPA-0.3026(R2=0.9861**)、N美33B=7.0997DPA-0.2814(R2=0.9807**)。     

低温条件下外源生理活性物质对棉铃发育的影响

和4月20日（正常播期）、6月15日（晚播）两个播期条件下．对棉花1～4果枝1、2果节棉铃及其对位果枝叶于花后15d和30d涂抹外源生理活性物质：6％蔗糖和0．6％符氨酰胺混合溶液（C＋N）、2％蔗糖和0．2％谷氨酰胺混合溶液（1／3C＋1／3N）及12%蔗精和1．2％谷氨酰胺混合溶液（2C＋2N）．各浓度处理的C／N比值相同。统计正常播期铃龄50d和纤维加厚发育期（铃龄25～50d）日均温分别为28．5℃、28．1℃．晚播铃龄50d和纤维加厚发育期日均温分刖为22．9℃、21．4℃（超过了相应的临界温度21℃和18℃）。试验结果表明．晚播条件下,花后15dC＋N处理以及花后30d 2C＋2N处理促进了氮和可溶性糖的运转．均使铃重增加最大,分别达0．40g和0．58g。3种浓度外源生理活性物质均增加了纤维素的累积量．且于花后30d促进了螺旋角（φ）和取向分布角（ψ）的优化．提高了纤维比强度．其中以2C＋2N处理提高纤维比强度幅度最大．达1．45cN／tex。花后15d以1／3C＋1／3N处理对提高纤维比强度最有利．达2．10cN／tex。     

棉花幼铃脱落过程中IAA、ABA、MDA含量及SOD、POD活性的变化

经去柱头阻止受精或去叶处理即将脱落的棉幼铃,随脱落进程加快,其内在生理变化均伴随膜脂过氧化加剧、ABA含量增加、POD活性提高,在脱落前达到最大值,而正常幼铃的变化平稳;IAA含量则逐渐减少,并明显低于正常幼铃的;SOD活性在开花后的前3天呈上升趋势,并明显高于正常铃的,以后又逐渐下降。超氧自由基（O2）的积累及其引起的膜脂过氧化伤害可能是影响幼铃内源激素平衡,导致幼铃脱落的重要原因之一。     

棉花幼铃脱落过程中IAA、ABA、MDA含量及SOD、POD活性的变化

经去柱头阻止受精或去叶处理即将脱落的棉幼铃,随脱落进程加快,人在生理变化均伴随膜脂过氧化加剂、ABA含量增加、POD活性提高,在脱落前达到最大值,而正常幼铃的变化平稳;IAA含量则逐渐减少,并明显低于正常幼铃的;SOD活性在开花后的前3天呈上升趋势,并明显高于正常铃的,以后又逐渐下降。超氧自由基（O2^-）的积累及其引起的膜脂过氧化伤害可能是影响幼铃内源激素平衡,导致幼铃脱落的重要原因之一。     

低温条件下外源物质对棉株不同部位果枝棉铃纤维比强度的影响

在棉纤维加厚发育期20.0℃的日均温条件下,对棉花6~9果枝(中部果枝)和11~14果枝(上部果枝)1、2果节棉铃及其对位果枝叶分别于花后15 d和30 d,外施C/N比恒定的3种外源物质:(1)6%蔗糖和0.6%谷氨酰胺混合溶液(C+N),(2)6%蔗糖、0.6%谷氨酰胺和2μg.g-16-BA混合溶液(C+N+BA),(3)2μg.g-16-BA溶液(BA),研究低温条件下外源物质对棉株不同部位果枝棉铃纤维比强度的影响。结果表明:花后15 d外施C+N+BA可提高棉花上部果枝铃铃重和衣分,花后15 d3、0 d外施C+N+BA均可提高棉花中部果枝铃铃重和衣分。花后15 d3、0 d外施BA均有利于棉花上部果枝铃衣分的提高。花后15 d、30 d外施C+N、C+N+BA、BA均导致棉花上部果枝铃棉纤维的螺旋角和取向分布角变大,纤维比强度降低,但可优化中部果枝铃棉纤维的螺旋角和取向分布角,提高纤维比强度,且以BA处理效果最佳。     

低温胁迫对麻竹叶片和根系抗性生理指标的影响

采用室内人工低温处理,研究了麻竹(Dendrocalamus latiflorus)叶片及根部质膜透性、丙二醛、可溶性蛋白、可溶性糖含量,超氧化物歧化酶(SOD)、过氧化物酶(POD)活性和膜脂脂肪酸组成的变化,寻找与竹类植物耐寒性关系最密切的抗性生理指标。结果表明:低温预处理(8℃)15d后,麻竹叶片中可溶性糖、可溶性蛋白含量、POD活性显著提高,根部可溶性糖含量、POD活性显著升高;低温胁迫处理(-2℃)72h后,经低温预处理的麻竹叶片可溶性糖、可溶性蛋白质含量、SOD、POD活性显著高于未经低温预处理,而质膜透性显著低于未经低温预处理,但膜脂过氧化程度显著高于-2℃处理前;经低温预处理的麻竹根部SOD、POD活性及膜脂不饱和脂肪酸相对含量显著高于未经低温预处理,而质膜透性、膜脂过氧化程度较-2℃处理前无显著差异。说明剧烈降温对麻竹生理特征造成严重影响,叶片通过提高可溶性蛋白、可溶性糖含量,维持较高的POD活性以减轻低温伤害;根系则通过维持较高的SOD、POD活性以减轻低温下膜脂过氧化水平,并通过提高膜脂不饱和脂肪酸比例降低质膜透性来抵御低温对膜的伤害。     

不同有机肥影响菠萝生长的生理生化机制

以菠萝品种'澳大利亚卡因'为材料,研究了施用不同有机肥对菠萝长叶期和抽蕾期植株生长量、生理生化指标以及土壤酶活性、微生物等的影响,以探讨不同有机肥对菠萝生长的影响机理.结果显示:(1)在花生麸处理中菠萝株高、青叶数、地上部和根鲜重较对照(施用化肥)提高,而在鸡粪和水肥处理中株高、青叶数、地上部鲜重较对照降低.(2)花生麸处理的菠萝叶片细胞膜透性较对照降低,而叶绿素含量、根系活力以及叶片和根系的可溶性糖、可溶性蛋白含量、SOD活性均较对照提高;鸡粪和水肥处理的叶片细胞膜透性和根系SOD酶活性较对照提高,而叶绿素含量、根系活力、长叶期叶片和根系的可溶性糖含量、长叶期和抽蕾期叶片的可溶性蛋白含量、叶片SOD酶活性均比对照降低.(3)花生麸能提高土壤脲酶、转化酶和过氧化氢酶的活性及土壤微生物数量;鸡粪和水肥能降低土壤脲酶、蛋白酶活性,却能增强土壤转化酶、过氧化氢酶活性,鸡粪使土壤微生物数量增加,水肥使长叶期土壤微生物数量增加,但使抽蕾期的减少.研究表明,施用花生麸能提高菠萝叶绿素含量、根系活力以及叶片和根系的可溶性糖、可溶性蛋白含量,并增强根和叶的SOD活性,同时增加了土壤相关酶活性和微生物数量,从而有效促进菠萝植株生长.     

棉花铃期与棉籽干物质积累模拟模型

基于不同熟性棉花品种的异地分期播种试验,综合量化品种特性、主要气象条件（温度、太阳辐射）和栽培措施（施氮量）对棉花铃期与棉籽干物质积累的影响,基于生理发育时间,建立棉花铃期模拟模型,并基于棉籽生长的“库限制”假设,建立棉籽干物质积累模拟模型.通过量化棉铃对位叶氮浓度的变化,为模型构建氮素效应函数.利用不同生态点的品种、播期和施氮量田间试验资料对模型进行检验,结果表明：德夏棉1号、科棉1号和美棉33B的铃期预测值与实测值的根均方差（RMSE）分别为2.25 d、2.61 d和2.75 d,科棉1号和美棉33B的棉籽干物质模拟值与实测值的RMSE分别为9.5 mg·seed^-1和8.2 mg·seed^-1.表明该模型预测精度较高.     

氮素对不同开花期棉铃纤维比强度形成的生理基础的影响

于2005年在江苏南京(长江流域下游棉区)和徐州(黄河流域黄淮棉区)棉田设置不同氮素水平(零氮：0 kg N·hm^-2,适氮：240 kg N·hm^-2,高氮：480 kg N·hm^-2)试验,研究氮素对不同开花期棉铃(伏前桃、伏桃和秋桃)纤维比强度形成生理基础的影响.结果表明：与适氮处理相比,零氮处理显著降低了棉铃对位叶氮浓度,增加了C/N,影响程度随开花期的推迟而加大,导致伏桃、秋桃对位叶制造和运输光合产物的能力在棉铃发育中后期大幅度下降,棉纤维的相对生长速率以及纤维发育关键酶蔗糖合成酶和β-1,3-葡聚糖酶活性降低,纤维素快速累积持续期缩短,纤维比强度显著降低;高氮处理显著增加了棉铃对位叶氮浓度,降低了C/N,影响程度随开花期的推迟而降低,其降低了伏前桃、伏桃发育过程中光合产物向纤维分配的比例、棉铃发育前中期的纤维发育关键酶活性及纤维素累积速率,导致其纤维比强度亦显著降低.综合分析认为,适宜的施氮量可以协调棉花的“源库”关系,有利于促进不同开花期棉铃高纤维比强度的形成.与适氮处理相比,零氮处理的伏前桃、伏桃和秋桃纤维比强度分别降低了1.8%、5.8%和13.0%,高氮处理则分别降低了8.2%、7.4%和-2.4%.     

土壤水分胁迫对小麦根系与旗叶衰老的影响

随土壤水分胁迫加剧,旗叶,根中的超氧化物歧化酶,过氧化氢酶活性降低,腊脂过氧化产物丙二醛含量增加,花后１４ｄ为膜脂过氧化作用加重的转折点,此时受水分胁迫愈重,旗叶与根中ＳＯＤ,ＣＡＴ活性降低愈迅速,ＭＤＡ含量迅速升高,根系活力,旗叶与根中可溶性蛋白含量骤降,加重了膜脂过氧化程度,降低了清除了自由基能力,加速植株衰老。     

Antagonism of Gibberellin to the Ethrel Induced Abscission of Cotton Boll

In order to study the antagonism of plant growth hormones to the ethylene induced abscission of cotton boll. The results of a series of experiments are summarized briefly as follows: First of all, we found that ethylene had abscission-promoting effect on cotton boll. The percentage of abscission of cotton boll induced by ethrel was 100%. The abscission-promoting effect of ethylene on the cotton boll was inhibited not only by gibberellin but also by zeatin. At the end of the experiment it was found that the ovaries which were treated with ethrel in the presence of gibberellin or zeatin can continue to grow and develop into parthenoearpie fruits. In addition, the growth and development of the cotton boils, especially seeds and fibres, were significantly affected by ethylene in the presence of gibberellin.     

棉花化学催熟与脱叶的生理基础

从棉铃开裂和棉叶脱落的生理过程、化学催熟剂和脱叶剂作用的生理机制、不同种类催熟剂和脱叶剂复配/混用的方式等方面介绍了棉花化学催熟与脱叶的生理基础以及影响催熟剂和脱叶剂作用效果的因素,并对这一领域的研究作了展望.     

Diversity of Boll Weevil Populations in South America: A Phylogeographic Approach

A phylogeographic approach was conducted to assess the geographic structure and genetic variation in populations of the boll weevil Anthonomus grandis, which is the most harmful insect pest of cotton in the Americas. COI and COII mitochondrial gene sequences were analyzed to test a former hypothesis on the origin of the boll weevil in Argentina, Brazil and Paraguay, using samples from Mexico and USA as putative source populations. The analysis of variability suggests that populations from South American cotton fields and nearby disturbed areas form a phylogroup with a central haplotype herein called A, which is the most common and widespread in USA and South America. The population from Texas has the A haplotype as the most frequent and gathers in the same group as the South American populations associated with cotton. The sample from Tecomán (México) shows high values of within-nucleotide divergence, shares no haplotype in common with the South American samples, and forms a phylogroup separated by several mutational steps. The sample from Iguazú National Park (Misiones Province, Argentina) has similar characteristics, with highly divergent haplotypes forming a phylogroup closer to the samples from cotton fields, than to the Mexican group. We propose that in South America there are: populations with characteristics of recent invaders, which would be remnants of “bottlenecks” that occurred after single or multiple colonization events, probably from the United States, and ancient populations associated with native forests, partially isolated by events of historical fragmentation.     

Approach to Physiological Functions of Ethrel in the Ripening of Cotton Boll

Both leaf and boll of cotton can absorb ethrel and the acceptor releases ethylene rapidly. Ethrel absorbed by leaves can release ethylene in bolls, whereas that absorbed by bolls cannot release ethylene in leaves. Bolls treated with ethrel has two peaks in ethylene releasing. The first peak appears about two days after treatment, and the second appears before the splitting of boll. The control has only one peak in ethylene releasing which appears eight days later than the second peak of the bolls treated with ethrel. This coincides with the fact that ethrel enables bolls to split seven to ten days earlier. The releasing of ethylene by cotton bolls is closely related to temperature, and is accelerated with increasing temperature no matter cotton bolls are treated with ethrel or not.     

Ascorbic Acid Turnover in Cotton Boll as Affected by Foliar Application of Sucrose

Excision of main stem leaf subtending the sympodium decreasedascorbic acid turnover in the developing boll (cotton fruit)on the first node of this sympodium in var. Suvin Gossypiumbarbadense L). Ascorbic acid turnover increased substantiallyin seed cotton and carpels of the boll when sucrose was appliedto the source leaf even though the main stem leaf remained excised.The role of ascorbic acid if any in boll growth appeared tobe linked with sucrose transport. Ascorbic acid, sympodial leaf, sucrose, boll     

Boll weevil (Coleoptera: Curculionidae) survival through cotton gin trash fans

There is concern that cotton gins may serve as loci for reintroduction of boll weevils, Anthonomus grandis grandis Boheman, to eradicated or suppressed zones when processing weevil-infested cotton from neighboring zones. Previous work has shown that virtually all weevils entering the gin in the seed cotton will be removed before they reach the gin stand. Those not killed by the seed cotton cleaning machinery will be shunted alive into the trash fraction, which passes through a centrifugal trash fan before exiting the gin. The objective of this study was to determine survival potential of boll weevils passed through a trash fan. Marked adult weevils were distributed in gin trash and fed through a 82.6-cm (32.5-in.) diameter centrifugal fan operated across a range of fan-tip speeds. A small number of boll weevils were recovered alive immediately after passage through the fan, but all were severely injured and did not survive 24 h. In another experiment, green bolls infested with both adult- and larval-stage weevils were fed through the fan. Several teneral adults survived 24 h, and there was no evidence that fan-tip speed affected either initial survival of weevils, or the number of unbroken boll locks that could harbor an infesting weevil. Thus, designating a minimum fan-tip speed for ensuring complete kill is not possible for the boll weevil. Experiments suggest that a device installed in a gin that partially crushes or cracks bolls open before entering a trash fan will increase mortality, possibly enough that further precautions would be unnecessary.     

Using an Electronic Nose to Rapidly Assess Grandlure Content in Boll Weevil Pheromone Lures

Samples of pheromone lures used in boll weevil,Anthonomus grandis (Boheman),eradication programs are routinely analyzed by Gas Chromatography (GC) to ensure lures are adequately dosed with grandlure,the synthetic aggregation pheromone produced by male weevils.However,preparation of GC samples is tedious,time consuming,and requires a moderate level of experience.We examined the use of a commercially-available electronic nose (e-nose) for rapidly assessing the grandlure contents of lures.The e-nose was trained to recognize headspace collections of grandlure emitted from new lures and after lures were aged under field conditions for 4 d,7 d,10 d,and 14 d.Based on cross-validation of the training set,the e-nose was 82％accurate in discriminating among the different age classes of lures.Upon sampling headspace collections of pheromone from a different set of field-aged lures,the e-nose was ＜50％ accurate in discriminating 4 d,7 d,and 10 d aged lures from the other ageclasses of lures.However,the e-nose identified new and 14 d aged lure samples with 100％ accuracy.In light of these findings,e-nose technology shows considerable promise as an alternative approach for rapidly assessing the initial grandlure contents of lures used in boll weevil eradication programs.     

高温胁迫对海岛棉光合生理及棉铃发育的影响

该试验于2018和2019年在新疆阿克苏地区阿瓦提县新疆农业科学院试验基地进行,采用田间搭设增温棚的方式于盛花期进行为期 3 d(H3)、6 d(H6)和 9 d(H9)的增温处理,以大田自然状态为对照(CK),研究花铃期增温对海岛棉光合生理及棉铃发育的影响。结果显示：(1)花铃期不同天数高温胁迫均导致棉铃对位叶蒸腾速率(T_r)、胞间 CO₂浓度(C_i)上升, 净光合速率(P_n)下降。(2)随着高温处理时间的延长,棉铃对位叶PSⅡ 的最大量子效率(F_v/F_m)、PSⅡ 的实际光量子产量(Φ_PSⅡ)、光化学淬灭(qP)、光合电子传递的相对速率(ETR)呈规律性降低趋势,而初始荧光(F_o)、非光化学淬灭(NPQ)呈上升趋势,且H3、H6和 H9 处理较CK差异显著(P<0.05),其中各参数快速上升或下降的阶段大多发生在高温持续3～6 d。(3)随着高温胁迫时间的增加,棉籽、纤维干物质量降低趋势明显;单株结铃数、单铃重、衣分、皮棉产量均呈显著下降趋势;高温还影响了棉铃发育,造成棉铃长度、体积减小。研究表明,在短期高温胁迫下,海岛棉铃对位叶光合能力的显著下降,主要是由非气孔因素导致的;持续高温胁迫导致PSⅡ的开放程度减小,电子传递能力下降,光合作用受到抑制,棉铃发育和产量构成因素均受到负面影响,最终导致产量降低。