新疆奎屯棉花脱叶催熟剂的混用效果研究

为筛选适宜于新疆奎屯垦区棉花的最佳脱叶催熟剂品种,开展了不同脱叶催熟剂对棉花脱叶效果及产量品质影响的田间小区试验。结果表明,至喷施后20d,所有脱叶催熟剂处理的叶片脱落率均达到70%以上,且T1、T2与T3、T4棉花叶片脱落率差异不大,但T1、T2处理均显著高于单施乙烯利处理。各处理棉铃吐絮率均在90%以上,且不同脱叶催熟剂处理间差异不大,说明所有脱叶催熟剂的催熟效果均较好。喷施脱叶催熟剂后棉花产量、单铃重、衣分、子指、绒长、整齐度指数、断裂比强度、马克隆值、短纤维指数、棉纤维成熟度比等指标较对照无明显差异,说明喷施脱叶催熟剂对棉花产量及品质影响不大。从喷施次数来看,2次喷施的脱叶和吐絮效果略优于1次喷施,但差异不大;棉花品质较1次喷施有轻微降低。因此,综合比较来看,T1处理的脱叶、吐絮效果均较好,且瑞脱龙价格适中,适宜在新疆奎屯垦区大面积推广。     

我国棉花脱叶催熟技术研究进展

化学脱叶催熟技术是棉花机械收获的重要前提,是机采棉综合农艺配套技术的关键环节。合理施用脱叶催熟剂能够提高机采棉的脱叶吐絮质量,降低籽棉的含杂率,对解决新疆棉花品质问题具有重要意义。然而,当前棉花脱叶催熟剂存在有效成分单一、剂型同质化严重、喷施装备及喷施技术落后,造成籽棉含杂率高,严重影响棉花品质。本文评述了机采棉脱叶催熟剂及其施用的研究现状,总结提出了棉花脱叶催熟剂存在的问题及解决途径,对今后棉花脱叶催熟剂减施增效的前景和研究方向做了展望。     

新疆棉区植保无人机喷施棉花脱叶催熟剂效果研究

【目的】明确植保无人机喷施棉花脱叶催熟剂田间作业现状、作业效果,为构建新疆生产建设兵团棉花脱叶催熟剂喷施作业技术体系以及无人机在棉花脱叶催熟作业中的推广应用提供依据。【方法】以市场主流无人机对比喷杆喷雾机进行田间试验,评价和分析不同作业区棉花脱叶和吐絮效果。【结果】药后22 d,无人机两次施药的棉花脱叶率在82.2%～92.1%,吐絮率在85.8%～100%,脱叶效果显著好于地面喷杆喷雾机一次顶喷施药,催熟效果差异不大;不同无人机以及同一无人机不同作业区,对棉花的脱叶催熟效果不同,无人机喷雾施药的8个作业区中,仅有1个能同时满足兵团棉花机械采收对脱叶率和吐絮率的要求。无人机部分施药作业中存在作业参数选择不当、作业不规范以及因无人机自身设备性能未达最优而导致的药液喷施不均匀、漏喷等现象。【结论】采用无人机喷施棉花脱叶催熟剂施药技术有待进一步优化完善。     

脱叶催熟剂喷施时间对不同部位棉铃发育和纤维品质的影响

【目的】研究不同时间喷施脱叶催熟剂对棉花不同部位棉铃的干物质质量、产量性状以及纤维品质等的影响，明确河北省喷施棉花脱叶催熟剂的最佳时期。【方法】以机采棉品种冀丰1458为供试材料，分别于2020年和2021年的9月下旬到10月上旬，设置4个时间喷施50%（质量分数）噻苯·乙烯利悬浮剂，以9月20日喷施等量清水作为对照，分析棉花的脱叶率和吐絮率、不同部位棉铃的干物质质量、铃重、籽指与衣分、籽棉产量、皮棉产量和纤维品质等指标的变化。【结果】各处理喷施脱叶催熟剂当天的吐絮率为40%～65%，处理后20 d的吐絮率和脱叶率均大于90%。与对照相比，9月20日处理的上部棉铃的铃重、籽指、衣分、纤维上半部平均长度、断裂比强度、马克隆值均显著降低；9月20日或9月25日左右喷施，上部、中部棉铃的干物质质量和单株棉铃总干物质质量均显著降低；9月20日至10月5日左右喷施脱叶催熟剂导致上部棉铃籽指显著降低，籽棉产量和皮棉产量显著提高，其中9月30日左右处理的籽棉和皮棉产量最高，并且其纤维品质综合表现也较好。【结论】初步认为，河北省植棉区露地直播棉田脱叶催熟剂的最佳喷施时间为9月30日、吐絮率为56%左右...     

棉花脱叶催熟剂对纤维品质的影响及应用时间的确定

棉花脱叶催熟技术是实现棉花机械采收的重要前提,确定脱叶催熟剂喷施时期及标准对实现良好的脱叶和催熟效果至关重要。本研究采用分期喷施脱叶催熟剂的方式,探讨了脱叶催熟剂对纤维品质的损伤程度,及与棉铃铃期之间的定量关系。结果表明,脱叶催熟剂对纤维长度的影响在品种间存在差异, 46%～69%的供试品种纤维长度较对照下降或持平,另有31%～54%的品种纤维长度反而较对照增加,所有品种纤维长度较对照平均仅降低0.2%～1.2%。纤维比强度受脱叶催熟剂的影响较为明显,其损伤量(处理与对照的差值)集中分布在-4～0 cN tex~(-1)之间。脱叶催熟剂对纤维比强度的损伤程度与喷施时间有关,铃龄30 d时喷施损伤大,铃龄37 d时喷施损伤减小,且有61%供试品种的比强度较对照平均增加了1.1cN/tex。脱叶催熟剂对纤维比强度的损伤量随棉铃铃期延长而加剧,因此可根据"脱叶催熟剂喷施时棉铃的铃龄与铃期的比值(Rd/b)"这一指标确定脱叶催熟剂的喷施时间。此外,棉铃铃期与棉铃体积、棉铃体积与纤维比强度均呈显著正相关关系。如要生产比强度31 cN tex-1的棉花纤维,所选品种的棉铃体积应31.8 cm3、棉铃铃期应60.0 d,且要在Rd/b0.68 (铃龄40.9 d)后喷施脱叶催熟剂(可控制纤维比强度损伤量小于0.5 cN tex~(-1))。     

机采棉田脱叶催熟效果试验初报

脱叶催熟技术是机械化采棉配套措施之一。通过脱叶催熟剂的不同喷施时间、不同用量和不同配方试验，筛选出以脱落宝20g 乙烯利100g配方脱叶催熟效果最好且用量少、成本低；喷施时间以日平均温度20℃以上效果最好；随着处理时间推迟，用量大，效果不好，成本增高。施用脱叶催熟剂对棉花品质有一定的影响，施用越早影响越大。     

脱叶剂对棉花叶片叶绿素荧光动力学参数的影响

利用叶绿素荧光动力学测定技术,对脱叶剂的不同喷施时间条件下棉花叶片光能吸收、传递、转换特性及棉花产量进行了研究。结果表明喷施脱叶剂降低了棉花叶片的光合功能,降低了最大光化学效率(Maximum photochemical efficiency,Fv/Fm)及PSⅡ反应中心开放部分的比例,使初始荧光(Minimal fluorescence,Fo)上升、光合电子传递速率(Electron transport rate,ETR)和PSⅡ总的光化学量子产量(Photosynthetic quantum yield,Yield)降低,提高了非光化学猝灭系数(Non-radiant energy,NPQ),说明脱叶剂胁迫下棉花叶片发生了光抑制,PSⅡ复合体受到损伤伴随着光合电子传递受阻。吐絮率10%时喷施脱叶剂使棉花铃重、衣分、皮棉产量显著低于对照。吐絮率50%时喷施脱吐隆300 g·hm~(-2)+40%乙烯利1200 m L·hm~(-2),第25天棉花脱叶率为90.1%,吐絮率为99.87%,对棉花铃重、衣分及皮棉产量影响最小且更有利于促进叶片脱落和棉铃成熟。     

高风险棉区机采棉脱叶剂的应用效果研究

通过设置小区试验探究了3种脱叶剂在棉花上的应用效果,为研究区开展棉花脱叶技术提供科学依据。以主栽棉花品种新陆早45号为供试材料,设置4个处理,测定了棉花的脱叶效果、产量及纤维品质,对脱叶剂的应用效果进行综合评价,结果表明,喷施脱叶剂对棉花的脱叶率和吐絮率有显著影响(P 0.05)。喷施瑞脱龙20 d后脱叶率和吐絮率分别达到89.2%和92.1%,显著高于其它处理(P 0.05)。喷施脱叶剂后对棉花的单铃重、衣分、单株结铃数及产量影响较小,处理A、处理B及处理C与对照处理D差异不显著(P 0.05)。喷施脱叶剂后对棉花纤维的长度、整齐度、伸长率、成熟度及马克隆值影响较小,处理A、处理B及处理C与对照处理D差异不显著(P 0.05)。试验证明,处理B(瑞脱龙+助剂+乙烯利)最适宜在本研究区使用。     

机采棉脱叶剂喷施方案的优化

通过喷施脱叶剂来调控棉花脱叶和吐絮已经成为机采棉花的重要管理手段。为进一步提高棉花脱叶催熟效果,本文对脱叶催熟喷施方案进行了优化。试验结果表明,脱叶剂喷施2遍较喷施1遍效果好,棉花脱叶率和吐絮率分别可达96.7%、98.3%;加施乙烯利时,宜在第2遍与脱叶剂一同喷施,脱叶率和吐絮率分别可达99.6%和99.7%。     

吡草醚对棉花催熟作用研究

为了明确吡草醚对棉花催熟效果,探明吡草醚催熟对棉花产量和品质性状的影响,采用田间试验及室内药效测定方法,对施用2%吡草醚ME后棉花叶片脱落速度、吐絮率及产量结果等进行分析。结果显示:2%吡草醚ME脱叶、吐絮效果明显,与常规脱叶剂噻苯隆相当;药后30天收获籽棉产量比清水对照区增加10.75%~21.60%,霜前花比例增加显著;单铃重减小、僵桃增多;对衣分、纤维长度等品质指标影响不明显。吡草醚具有安全性好、脱叶速度快、棉铃吐絮早、大幅度提高霜前花比例等优点,可以作为一种新型的棉花脱叶催熟剂推广应用。     

Effect of Defoliants Application on Physiological Characters of Cotton Leaf without Defoliants

[Objective]The aim of this study is to elucidate the physiological mechanism of cotton leaf without defoliant response to thidiazuron (TDZ). [Method] A pot experiment was conducted to study the effect of defoliants on the photosynthesis, chlorophyll fluorescence, antioxidant enzyme activity, and endogenous hormone contents of cotton leaf without defoliant at 1 d, 3 d, 6 d and 10 d after the application of TDZ. Cultivar CCRI-50 was used for this experiment. [Result] TDZ rapidly induced cotton leaf abscission, however, no abscission was detected to the cotton leaf without defoliants. The net photosynthetic rate (P_n) of cotton leaf without defoliants was reduced by 1 d, 3 d and 6 d after TDZ applied, but rise to the control treated with water level by 10 d. TDZ also caused a significant decline in the maximum photochemical efficiency of photosystem II (F_v/F_m), the quantum yield of electron transport (Φ_PSII), the electron transport rate (R_et) and the photochemical quenching coefficient (q_P), but an increase in the non-photochemical quenching coefficient (qNP). However, with the same changes as P_n, the chlorophyll fluorescence characters got to the control by 10 d. TDZ application significantly increased the superoxide dismutase activity, did not affect the peroxidase activity, decease the malondialdehyde content. Abscisic acid contents in the cotton leaf without defoliant were lower than control by 3 d and 6 d after the applied of TDZ, but have the same level with control at 10 d, and the auxin had a little changes compared with control during the whole period of experimental time. [Conclusion] TDZ application significantly affect the photosynthesis, chlorophyll fluorescence, antioxidant enzyme activity, and endogenous hormone contents of cotton leaf without defoliant. When the leaf with defoliant drop off, the physiological characters of cotton leaf without of defoliants recovered to control level, and no abscission were detected.     

Responses and Underlying Mechanisms of Different Mainstem Leaves on Cotton to Defoliant Thidiazuron

[Objective] This study elucidates the responses of different mainstem leaves on cotton to defoliant thidiazuron and reveal the underlying mechanisms. [Method] Cotton plants were raised hydroponically. At the ten-leaf stage, 4.54 mmol·L^－1 thidiazuron was evenly applied to all mainstem leaves, the youngest full-expanded leaf (the fourth leaf from apex) and the youngest leaf (the first leaf from apex). Then, the progress of abscission zone formation and shedding of each leaf was observed, and the expression level of genes related to ethylene synthesis and signal transduction in the fourth and first leaf from apex was analysed. [Result] The abscission zone developed in the following sequence: the first leaf from the top, then the lowest leaves (the ninth or tenth leaf from the top, 35-40 days old), and the fourth leaf from the top. However, the leaf abscission was in a different order: the earliest was the first leaf from apex, then the fourth leaf from apex, and the latest was the lowest leaves which were prone to wither and stick to the stalk. The GhACS1 expression was up regulated in both the first leaf and the fourth leaf from apex within 24 h after thidiazuron treatment. However, the expression of this gene changed more rapidly and sharply in the first leaf from the top than that in the fourth leaf from the top. In addition, the expression of GhACO1 (ethylene synthesis gene), GhEIN3 and GhERF23 (ethylene signal transduction genes) was significantly increased up to ten times in the first leaf from the top, whereas the expression of these genes did not change in the fourth leaf from the apex. [Conclusion] After exposed to defoliant thidiazuron, the time of the abscission zone formation of different leaves on cotton main stem is different, and the order of shedding is not consistent with that of abscission zone formation. The youngest ready to expand leaf abscises earlier than the youngest fully expanded leaf after thidiazuron treatment, which is possibly associated with the rapid expression change of genes related to ethylene synthesis and signal transduction in the former.     

棉花地上部形态建成的光温模型

以不同株型棉花品种为研究对象,基于“同类相似性”原理,借助数学建模和统计分析方法,系统分析光温生态因子对棉花叶片长、宽,叶柄长、粗,主茎节间长、粗,果节长、粗,蕾铃高、直径等形态指标的影响,量化温、光因子与棉花各器官形态建成的关系,构建了基于GDD (growing degree day)和Logistic方程的棉花形态建成光温模型。利用独立的试验数据对模型进行了检验,结果表明,棉花主茎叶片的长度和宽度、叶柄长度、主茎节间的长度和粗度、果枝叶片的长度和宽度、叶柄长度、果节的长度和粗度、蕾铃高度和直径的RMSE值分别为0.48、0.65、0.53、0.09、0.02、0.55、0.28、0.23、0.14、0.17、0.20和0.11 cm。显示棉花器官形态指标的模拟值与检验值具有较好的吻合度,说明模型具有良好的预测性和描述性。     

Chemical Defoliation of Machine-Harvested Cotton was Accompanied by Intense Ethylene and Cytokinin Signal Responses

[Objective] Chemical defoliation is a necessary technical measure for machine-harvested cotton, and the effect of chemical defoliation directly affects the efficiency of mechanical-picking and fiber quality. Study on the molecular mechanism of defoliant in regulating defoliation could effectively guide the screening and improvement of defoliant-sensitive cotton germplasms. [Method] In this study, 200 cotton accessions were collected and planted in greenhouse, and treated with defoliant at the early flowering stage. Different varieties with high or low sensitivity to defoliant were selected according to the defoliation rate on the 4th day after treatment. The selected cotton varieties were also treated with defoliant at the boll opening stage in the field, and the defoliation rate on the 7th day after treatment was calculated. Meanwhile, samples from the abscission zone of the selected varieties were collected on the first and third day after treatment. And the expression of ethylene-, cytokinin- and hydrolase- related genes were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). [Result] Six defoliant sensitive and 6 insensitive varieties were selected from greenhouse and field tests. According to the qRT-PCR results, cytokinin-related genes, ethylene-related genes and hydrolase-related genes showed different expression patterns following defoliant treatment in different varieties, and most of these genes showed significant different expression in the defoliant sensitive and insensitive varieties. [Conclusion] This study indicates that different cotton germplasms respond to differently to defoliant, which might be the result of differential expression of cytokinin- and ethylene-related genes.     

玉米叶片“源”的高温胁迫阈值研究

为了明确玉米叶片“源”的高温胁迫温度阈值,采用盆栽试验,利用可精准控温（模拟大气温度变化）的人工气候室,以日最高温32℃为对照,分别设置日最高温34℃、36℃和38℃ 3个处理,于玉米拔节期进行持续10d的温度控制试验,比较叶片光合作用光反应和暗反应阶段对不同高温的响应,以及叶片气孔和叶绿体超微结构的变化。光反应阶段,38℃处理下的光系统Ⅱ最大光化学量子产量（F_v/F_m）和实际光化学量子产量Y（Ⅱ）与其他处理相比均显著降低,但胁迫解除后均恢复至正常水平,而其他3个处理无显著性差异;暗反应阶段,与对照相比,36℃和38℃处理的叶片净光合速率（P_n）均显著降低,胞间CO₂浓度（C_i）均显著升高,且38℃处理在胁迫解除后P_n未能恢复。透射电镜结果显示,在36℃和38℃处理下,叶绿体结构逐渐紊乱降解,脂质球体含量增加,淀粉粒合成减少。综上可知,对于玉米叶片“源”,日最高温的胁迫阈值是36℃,阈值附近的高温胁迫主要是限制光合作用的暗反应阶段。     

Effect of Thermal Energy Intensity on Time and Rate of Nitrogen Accumulation by Maize (Zea mays L.)1

The effect of thermal energy intensity (TEI) on the rate of nitrogen (N) accumulation by maize from a Hamerly clay loam soil (Aerie Calciaquoll) was examined with and without supplemental irrigation. Soil- and air-TEI expressed as cumulative growing degree days (GDD) was determined from hourly temperature measurements taken within each plot at soil depths of 0.05-, 0.15-, and 0.3-m and at a height of 1.2-m above ground surface. A daily mean TEI (GDD per day) was calculated for each growth period. Estimates of time coefficient(s), k, in uni- and diphasic tanh[k(time)] functions, plotted against mean TEI for the periods; 1) planting to emergence, 2) emergence to eighth leaf, 3) eighth leaf to time(s) of maximum N accumulation rate, (t₀), 4) planting to t₀, 5) emergence to t₀, 6) first diphasic maximum accumulation rate (t₀₁) to 50 % silking, and 7) silking to second diphasic maximum accumulation rate t₀₂ showed several linear relationships. Uniphasic time coefficients were modelled as functions of air-TEI. The first diphasic time coefficient, k₁ was modelled as a function of pre- and post-emergent soil-TEI. Attempts to model k₂, the second time coefficient of the diphasic model were unsuccessful; however, this time coefficient was linearly related to TEI for the growth period ‘t₀₁, to 50 % silking’ and curvilinearly related to k₁.     

障碍型冷害对石河子棉区花铃期棉花生长的影响研究

为了明确棉花主栽品种耐冷性及障碍型冷害的量化指标,达到及时预报,减轻损失的目的。运用智能人工气候箱,在新疆石河子棉区乌兰乌苏农业气象试验站内,于2003-2005年进行低温冷害模拟试验,研究花铃期棉花在经受不同范围和时长的低温后,其植株的受害程度。结果表明,低温处理之后,棉花的叶片、蕾和幼铃都出现异常脱落,经过11.5~18.5℃处理2~4天的其叶片在第8天后才开始异常脱落,其减少率≥35%,并呈持续减少的趋势,而其蕾、幼铃在第6天后就开始异常脱落,减少率≥55%;经过11.5~22.5℃处理2~4天其叶片减少率≤25%,并在处理后的第18~23天基本保持稳定,其蕾、幼铃减少率≥70%。说明花铃期棉花在受冷害之后,其蕾、幼铃先于叶片出现异常脱落,其减少率大于叶片,经过2种相同最低温度不同最高温度的处理,温度日较差小的叶片减少率较高。