施氮量对新疆滴灌冬小麦根系生长及产量的影响

为探明滴灌冬小麦高产需氮肥规律,利用大田试验研究了N_0(0 kg·hm~(-2))、N_1(90kg·h~(-2))、N_2(180kg·h~(-2))、N_3(270kg·h~(-2))、N_4(360kg·h~(-2))施氮量对新冬18号0~60cm土层根系生长的影响及其与产量和氮肥利用率的关系。结果表明,随着施氮量的增加,拔节至成熟期间0~60cm土层根系干重、根长和根系活力均增加,N_3处理孕穗期小麦0~60cm土层根干重、根长分别较N_0处理增加11.93%、29.0%,增幅基本表现为0~20cm20~40cm40~60cm土层;N_3处理较N_0处理小麦产量增加30.35%,氮肥农学利用效率为6.90kg·kg-1。拔节期前后施适量氮肥可促进0~60cm土层根系生长和活力增强,是氮肥增产的重要原因。本试验条件下最适宜施氮量为180~270kg·h~(-2),可获得产量7 591.49~8 004.85kg·h~(-2),氮肥农学利用效率为6.90~8.06。     

播种方式和种植密度对冬小麦根系生长和产量的影响

为探究播种方式和种植密度对冬小麦根系生长和产量的影响,以新冬22号为材料,采用二因素裂区试验设计,主区设条播（DR）和匀播（UN）2种播种方式,副区设150万粒·hm^-2（D150）、225 万粒·hm^-2（D225）、300万粒·hm^-2（D300）和375万粒·hm^-2（D375）4种种植密度,比较分析了不同播种方式和种植密度下冬小麦根系形态特征、根系伤流量和产量的差异。结果表明,随种植密度的增加,小麦总根干重、总根长呈先增后减趋势,单株次生根数、根系伤流量呈减小趋势。与条播相比,匀播下小麦总根干重、总根长显著增加,差异主要在0~30 cm土层;单株次生根数、根系伤流量增加,差异主要在生育中后期;产量显著提高（增幅9.89%）,其中以D225处理最大。综上,匀播能够促进小麦根系的生长,提高根系活性,有利于高产;在本试验条件下匀播小麦以225万粒·hm^-2种植密度最佳。     

调亏灌溉下冬小麦根系分布与耗水的关系

为探明调亏灌溉下冬小麦根系分布与耗水的关系,在大田条件下,以ND09-1、济麦22、烟农15、石家庄8号和潍62036为材料,研究了起身期、拔节期、开花期、花后20 d和成熟期0～200 cm不同土层冬小麦耗水动态与根系总重、总长以及根干重密度(DRWD)和根长密度(RLD)垂直分布的关系.结果表明,石家庄8号和济麦22开花期根系总干重、根系总长度、80～120 cm土层DRWD和RLD值都显著大于其他品种,花后20 d至成熟期间80～140 cm土层水分消耗量也明显大于其他品种,最终千粒重和产量也显著高于其他品种.提高灌浆后期深层根量有利于增强小麦植株利用深层水分的能力,保证灌浆后期的水分供应,实现节水高产.     

小麦根长密度和根干重密度对氮肥的响应及其与产量的关系

为总结施氮量与小麦根系生长及产量的关系,通过查询近30年（1993-2019年）中国主要麦区施氮量对小麦根长密度、根干重密度及产量影响的文献资料,对小麦适宜的施氮范围进行分析。结果表明,随着土层的加深,小麦根长密度(RLD) 和根干重密度(RDWD)总体上呈逐渐降低的趋势,且小麦根系主要分布在0～20 cm土层。不同施氮量下0～60 cm土层小麦开花期的RLD 和RDWD均高于成熟期,开花期的RLD 和RDWD分别在施氮220～235和192～209 kg·hm^-2时达到最大值,成熟期分别在施氮220～275和 171～212 kg·hm^-2达到最大值。经相关性分析,小麦产量与RLD、RDWD均呈显著正相关。通过对施氮量与小麦籽粒产量进行一元二次方程拟合得出,在施氮量为247 kg·hm^-2时小麦产量达到峰值。因此,在当前中国主要麦区向农户推荐氮肥用量时,需针对不同区域,结合农田实际,在施氮171～247 kg·hm^-2范围选择合理用量,以促进小麦根系的生长发育及籽粒产量的提高。     

不同水氮处理对滴灌冬小麦田耗水特性及水氮利用效率的影响

为给滴灌超高产冬小麦的水氮运筹提供依据,采用水、氮两因素三水平的田间裂区试验(灌水量设1 125、2 250和2 700m3·hm-2三个水平,分别用W_1、W_2和W_3表示;施氮量设0、180和270kg·hm~(-2)三个水平,分别用N_0、N_1和N_2表示),研究了9个水氮处理对麦田0~140cm土层耗水量、冬小麦品种新冬41号群体叶面积指数、干物质和产量及水、氮利用效率的影响。结果表明,增加滴灌量直接提高了0~60cm土层含水量,间接减少了小麦对60~140cm土层储水的消耗量,增加了麦田总耗水量;施氮量对土壤含水量影响不显著。在相同水分条件下,增加施氮量提高了小麦产量;而仅在N_2条件下,滴灌量显著影响产量,W_2和W_3的产量均显著高于W_1,但W_2和W_3间差异不显著;加大滴灌量或施氮量均增加孕穗至成熟期间群体叶面积指数、光合势和干物质积累量,减少花前营养器官储存物质的转运量、转运效率和对籽粒产量的贡献率,增加花后物质生产对籽粒产量的贡献率和产量,降低灌溉水利用效率和氮肥农学利用效率;适宜水氮组合较单灌水或单施氮处理增产更显著,并同时提高水、氮利用效率,以W_2N_2、W_3N_2组合产量较高(9 051.9、9 189.6kg·hm~(-2))。综合产量和成本,春季总滴灌量2 250 m~3·hm~(-2)(拔节期、孕穗期、开花期各750m3·hm-2)、总施氮量270kg·hm~(-2)(拔节期90kg·hm~(-2)、孕穗期180kg·hm~(-2))的水氮组合为北疆滴灌冬小麦超高产田水氮运筹的适宜模式。     

极端干旱区滴灌量对冬小麦水氮利用及根系分布的影响

为明确新疆南部极端干旱区滴灌小麦的灌水量阈值,在常规沟灌(总灌量为3 750 m·hm^-2)的基础上,设计了四种减量滴灌模式(灌水量分别为3 376、3 000、2 625和2 250 m·hm^-2),分析了滴灌量对冬小麦产量、水氮利用效率及根系分布的影响。结果表明,土壤无机氮残留量因灌水量不同而异,灌水3 376和2 625 m·hm^-2时较低;各灌水条件下土壤无机氮残留量均随小麦生育期推进先降后升,在灌浆期达到最高,而后下降。随土层深度的增加,土壤中无机氮含量也逐渐递减。冬小麦水分利用效率随灌水量的增加呈先增后降趋势,灌水量在2 250 ~3 000 m·hm^-2范围内,随灌水量的增加,水分利用效率先逐步增加,而后下降。小麦根系长度随灌水量的减少呈递减趋势,当灌水量高于或低于3 000 m·hm^-2时,小麦根系出现早衰现象。     

土壤温湿度对玉米根系的影响

采用方形整段标本法,对河北省保定市固城镇中国气象局农业试验基地玉米（屯玉46）不同生育期的根系进行监测,同时对土壤水分、地温进行分析,研究土壤湿度、温度对玉米根系生长发育的影响。结果表明,拔节期和完熟期的根长密度在10～20 cm土层最大,分别为0.49 cm/cm³和1.98 cm/cm³,分别占0～100 cm土层总根长密度的49%和28%;抽雄期和乳熟期则是0～10 cm土层最大,分别为0.45 cm/cm³和1.17 cm/cm³,分别占0～100 cm土层总根长密度的34%和22%。对于土壤水分,50 cm土层以上,不同时期基本保持较为平缓的变化趋势,拔节期和抽雄期40～50 cm土层的水分为整层最大,分别可达18.84%和17.83%;乳熟期和完熟期为50～60 cm土层的水分最大,分别可达22.7%和22.0%。50 cm土层以上,不同生育期玉米根长密度的垂直分布均为向下递减;50 cm土层以下,乳熟期和完熟期的根长密度与土壤水分具有较为一致的变化趋势,水分较多的层次对应的根长密度较大,根系量较多。在土壤剖面中,不同生育期玉米根长密度增长量变化的垂直分布与土壤水分变化的垂直分布较为一致,无偏相关系数分别为0.38、0.9和0.7。地温越高,玉米侧根越细,温度对根系生长发育和生理活性产生一定影响。     

越冬期测墒补灌对冬小麦光合特性和水分利用效率的影响

为了解越冬期测墒补灌对冬小麦光合特性和水分利用效率的影响,于2013-2014年小麦生长季,选用高产冬小麦品种济麦22为材料,在大田条件下,依据0~40 cm土层进行测墒补灌。设置5个试验处理,即全生育期不灌水（W0）、越冬期不灌水（W1）、越冬期补灌至土壤相对含水量70%（W2）,越冬期补灌至土壤相对含水量75%（W3）及越冬期+拔节期+开花期各灌溉60 mm（W4）,其中W1、W2和W3处理在越冬期补灌基础上于拔节期和开花期分别补灌至土壤相对含水量的65%和70%,对不同水分条件下冬小麦叶片净光合速率、蒸腾速率、气孔导度、干物质积累、籽粒产量和水分利用效率进行了分析。结果表明,小麦各生育期总灌水量为W4＞W3＞W2＞W1＞W0。在灌浆中期,小麦旗叶净光合速率、蒸腾速率和气孔导度均表现为W4＞W2、W3＞W1＞W0,拔节期、开花期和成熟期干物质积累量表现为W4＞W2＞W3＞W1＞W0;W2处理开花后干物质积累量和对籽粒的贡献率与W4处理无显著差异,均显著高于W0、W1和W3处理;各处理籽粒产量表现为W4＞W2、W3＞W1＞W0;水分利用效率表现为W2＞W1、W3＞W4＞W0。依据0~40 cm土层进行测墒补灌,小麦越冬期土壤目标相对含水量达70%的W2处理的补灌水量低于W3和W4处理,籽粒产量和水分利用效率较优,分别为8 864. 46 kg·hm^-2和22.14 kg·hm^-2·mm^-1,是高产节水的最佳灌溉处理。     

玉米秸秆还田对砂姜黑土水分动态及冬小麦水分利用效率的影响

为给冬小麦水分高效利用提供科学依据,根据土壤-植物-大气连续体(SPAC)原理,利用野外小型蒸渗仪,以不施肥为对照(CK),原位研究了配方施肥(PF)以及配方施肥+秸秆还田(PF+JG)处理对砂姜黑土水分动态和冬小麦水分利用效率的影响.结果表明,秸秆还田主要影响0～40 cm土层土壤剖面水分含量,而40～80 cm土层土壤水分含量基本保持稳定.在小麦出苗期和拔节期,PF+JG处理的0～40 cm土层土壤含水量较PF处理分别提高50.9％和34.6％.土壤水分最大有效库容在小麦全生育期呈单峰变化趋势,峰值在返青期;PF+JG处理的出苗期土壤水分最大有效库容较CK和PF处理增加了8.25％和20.82％,拔节期增加8.07％和10.95％,且均差异显著(P＜0.05).PF+JG处理的土壤水分入渗量分别是CK和PF处理的4.53和3.55倍;小麦耗水量较PF处理降低9.2％;小麦产量和水分利用效率分别比CK和PF处理增加124.1％、18.8％和144.0％、30.8％,且差异达显著水平(P＜0.05).说明秸秆还田对冬小麦产量和水分利用效率的提高作用与增加土壤水分有效库容、水分入渗量和减少总耗水量有关.     

灌水和非灌水条件下冬小麦水分的利用特点研究

为了探讨灌水和非灌水条件下冬小麦对水分的利用特点,在大田条件下研究了灌水与非灌水两种处理对冬小麦的耗水结构、土壤水分利用程度及水分与产量之间的关系。结果表明,在非灌溉条件下,冬小麦主要利用20~60 cm土层中的水分,冬小麦对土壤贮水的消耗量增加,平均多耗水96.84 mm;土壤水分利用程度提高,较灌水区提高26.8个百分点;耗水系数增加,水分利用效率增大;冬小麦的产量与0~100 cm土层的含水量有密切的关系,这些土层内的含水量变动对产量的影响最大。     

留桩高度对再生稻根系的影响

以培矮64S/E32为材料,设10,15,20,25,30,35,40 cm等7个留桩高度处理,研究了留桩高度对头季根系进入再生季后的活力恢复与维持、再生根的发生等的影响.结果表明,再生根主要由低位再生苗产生;再生稻齐穗期,随留桩高度的降低,再生根根量及再生根根量占再生稻总根量的比例增大,而头季根根量减小;高留桩有利于头季根系活力的恢复与维持,而低留桩有利于再生根的发生.综合考虑根量、根系活力与吸收面积等因素,各留桩高度下,头季根仍是再生稻根系的主体.     

玉米初生根和次生根中铁、锰、铜、锌、钠含量分析

以玉米品种'掖单13'和'丹玉13'为试材,通过大田试验研究供试玉米的初生根和第1层至第9层次生根中的铁、锰、铜、锌和钠等元素的含量.结果表明:玉米根系中铁、锰、铜、锌和钠元素的平均值分别为6469,185,22,14,884mg/kg.玉米初生根中的铁元素与次生根相比其含量较低,锰、铜、锌和钠元素的含量较高,高于各次生根中的含量.玉米同一品种的不同类型根中各元素含量之间存在差异,不同品种相同类型根中的各元素含量存在相关关系.     

Characterization of the effect of high salinity on roots of Chloris gayana Kunth: carbohydrate and lipid accumulation and growth

Branched nodal roots comprise the largest portion of the root system mass in Chloris gayana Kunth and the effects of high salinity on nodal root appearance and elongation rates were analysed in cv. Boma in greenhouse experiments. Roots from salt-treated plants (0·2 mol l^–1 NaCl) were smaller than controls, and accumulated higher concentrations of soluble sugars and reserve lipids. The number of nodal roots was reduced by the saline treatment. Leaf, tiller and nodal root appearance were delayed by salinity but the correlation among these processes was maintained, indicating that the developmental pattern was not altered by this level of salinity, only its rate. Initial nodal root growth rates varied as a function of plant size and were decreased by salinity only after 2 weeks of treatment. When shoots of non-salinized plants were cut, a drastic reduction in nodal root appearance was observed, suggesting emerging leaves were stronger sinks than roots for available reserves. However, when the shoots of salt-treated plants were cut, the already depressed root appearance rate was not further reduced. This suggests that, under salinity, alterations in root ability to metabolize reserves could have been more significant than reserve availability for controlling elongation.     

Specific Variation in Shoot Growth and Root Traits Under Waterlogging Conditions of The Seedlings of Tribe Triticeae including Mizutakamoji (Agropyron Humidum)

Abstract

Waterlogging Stress is An Important Limiting Factor For Wheat and Barley Production. Waterlogging Tolerance Was Evaluated in The Seedlings of Seven Species From The Tribe Triticeae, including Wheat, Barley, Durum Wheat, Rye (Diploid and Tetraploid), Triticale, Einkorn Wheat, and Mizutakamoji (Agropyron Humidum), To Acquire Basic information About Their Variation in Waterlogging Tolerance and To Elucidate Opportunities For Genetic Improvement of Waterlogging Tolerance in Cultivated Wheat and Barley. The Seedlings At The One Leaf Stage Were Subjected To Waterlogging For 0 (Control: Ct) Or 12 Days (Waterlogging: Wt) in Plastic Cups (12 Cm Tall, 8 Cm in Diameter), and The Morphological Traits of Shoots and Roots Were Measured. Shoot Dry Weights (Dw) of Wheat (Cv. Norin 61) and Barley (Cv. Benkeimugi) Were Lower Under Wt By 73% and 59%, Respectively, Than Those in Ct. of All The Evaluated Genotypes, Only A. Humidum SHowed No Reduction in Shoot Dw Under Wt. The Relative Shoot Dw (W/C in Shoot Dw; Proportion of Shoot Dw in Wt To That in Ct) Was Significantly Correlated With Relative Root Dw (W/C in Root Dw). The W/C in Root Dw Correlated Significantly With W/C in The Number and Length of Adventitious Roots, and With W/C in Frequency of Branching Roots On The Seminal Root, Suggesting That Development of Adventitious Roots and Branching Roots Under Wt Might Be Related To Waterlogging Tolerance in Tribe Triticeae. The Results of This Study indicated That Wild Species of Tribe Triticeae, Such As A. Humidum, Might Be Useful Resources To Analyze Waterlogging Tolerance in Cultivated Wheat and Barley.     

Calcium translocation and accumulation into potato tubers

Summary Calcium uptake into potato plants was examined using test solutions containing 5% safranin dye (C₂₀H₁₉N₄C1 mw 350.85) and the radiotracer⁴⁵CaCl₂. When minitubers were suspended in test solutions for up to 5 days, safranin moved into the outer pith tissues while⁴⁵Ca²⁺ was located throughout the pith. Ca²⁺ is apparently taken up directly from the tubersphere by a slow diffusion process. Plantlets with one microtuber were used to investigate calcium uptake via basal roots.⁴⁵Ca²⁺ was well ahead of the safranin dye front in all plantlet stems.⁴⁵Ca²⁺ in shoot tips was significantly greater than in microtubers and no safranin entered the microtubers. Greenhouse-grown ex vitro plantlets with minitubers attached were used to determine the relative uptake by basal and stolon roots. Basal root feeding contributed significantly more⁴⁵Ca²⁺ to shoot tips and tubers than stolon root feeding while combined feeding gave the greatest shoot tip and tuber⁴⁵Ca²⁺ levels.     

橡胶园施肥穴胶树营养根分布规律研究初报

采用田间随机抽样法研究橡胶园施肥穴及其周边位置胶树营养根的空间分布规律,结果发现:未施肥和施过肥的穴内营养根占总根量比例分别为83.4%和94.7%,穴外营养根分布较少,主要为输导根;营养根密度大小在垂直方向以50￣60cm层为分界线,上层密集,高达38条/dm2,下层稀疏,平均为3条/dm2,表明挖穴能够培育庞大的橡胶树营养根体系。     

烟草不定根发生研究进展

烟草是我国重要经济作物之一。不定根的生理活性和数量对烟株的生长和烟叶的品质形成有着重要的影响,深入研究烟株不定根系形成的调控技术对提高我国烤烟质量有着重要意义。从基因、激素、外源因子等方面进行综述,总结当前国内外对烟草不定根形成的相关研究成果,以期能够为我国优质烟叶的科学生产提供有力的理论依据,并为实际生产中烟株不定根的诱导提供参考。     

花生根部特征与地上部分性状的相关性分析

通过田间试验分析12个广东省区试花生品种根系特征与地上部分性状的相关性.结果表明:根质量在各生育期均与地上部质量、总质量呈显著或极显著正相关关系:开花期根系活力与地上部分多数性状呈极显著正相关关系,不同时期的根系活力均与成熟期产量呈显著正相关关系;成熟期根冠比与产量呈显著负相关关系.说明花生根系特征与地上部分性状关系密切,花生生长后期保持根系活力对产量的形成具有重要作用.     

Nurturing of Plantlets Using Cut Pieces from the Storage Roots of Sweet Potatoes (Ipomoea batatas (L.) Lam.) and their Productivity in the Field

Abstract

A new nurturing method was studied using pieces cut from storage roots to reduce the time-consuming and laborious works (raising, preparing, and transplanting of cut sprouts), which accounts for about 60% of the total working hours in sweet potato production by the conventional method. The experiments were conducted in 1997 and 1998 using 1– and 10–g (fresh weight) cut pieces from storage roots (cultivar ; Koganesengan). Five kinds of growth regulators were applied at the concentrations ranging from 0 to 200 mg L^–1 to promote rooting and shooting from the pieces. After the treatment with growth regulators, the pieces were subjected to an antiseptic curing treatment, and then incubated on wet vermiculite at 30°C. Rooting was effectively induced by IAA, and shooting by ABA, within one to two weeks. The plantlets were developed from 10–g pieces with periderm after the treatment with ABA, and were nurtured for 10, 30 and 50 days. They vigorously grew with no transplanting injury after being planted in the field in early May. They were harvested in late October and were compared for shoot growth and productivity with the control (the conventional method using cut sprouts). The plantlets nurtured for 50 days achieved the highest yield and the best qualities and did not show the thickening of mother roots obserbed in direct planting using whole storage roots. In conclusion, the new nurturing method is superior to conventional methods in both productivity and quality. However, there are still several problems to be solved, such as low shooting rate and so on.     

Root System Development of Cassava and Sweetpotato during Early Growth Stage as Affected by High Root Zone Temperature

Abstract

Root zone temperature (RZT) is an important factor that affects the establishment of crops in the field. This study was conducted to determine the effect of high RZT on the root system development of cassava and sweetpotato and to assess the response of each root system component of cassava and sweetpotato to high RZTs. Cassava and sweetpotato are widely grown crops in soils that are prone to reach a high temperature especially during the dry season. The plant root system was the primary object of investigation in this study. Cassava and sweetpotato cuttings were grown in pots for 20 days in a growth chamber where two different soil temperature regimes were maintained : 40°C (high RZT) and 25°C (normal). High RZT significantly decreased the total length of the adventitious roots (ARs) and the number and total length of the first order lateral roots (LRs) in both cassava and sweetpotato. Reduction in these root growth parameters was greater in the latter than in the former. High RZT caused a marked increase in the number of the second order LRs in sweetpotato and tended to enhance the formation of the third order LRs. Under high RZT, in cassava, a higher proportion of the total number of ARs and the first order LRs, and thus, a greater fraction of the total root length came from the lower nodes of the cuttings that were buried deep in the soil at planting. In sweetpotato, a greater proportion of the total number and total length of the ARs and the first order LRs was observed in the nodes of the cuttings that were buried closer to the soil surface than those buried deeper. An opposite trend was evident in both cassava and sweetpotato grown under a normal RZT. In the screenhouse experiment where plants were grown for 12 days, root growth of cassava was significantly reduced by the high RZT that prevailed when the soil was not covered with mulch materials. The root development in the mulched soil was similar to that under normal RZT in the growth chamber.