Pot study on wheat growth in saline and waterlogged compacted soil: II. Root growth and leaf ionic relations

Soil compaction affects plant growth by causing increased resistance to root penetration and a decreased uptake of water and ions. A pot experiment was conducted to study the effect of soil compaction in conjunction with the soil salinity and waterlogging on root growth and leaf ionic composition of two wheat genotypes (Aqaab and MH-97). Compaction was achieved at a 10% soil moisture content by dropping 5 kg weight, controlled by a tripod stand for 20 times from 0.6 m height on a wooden block placed inside the soil-filled pots. Soil bulk density of non-compact and compact treatments was measured as 1.21 and 1.65 Mg m⁻³, respectively. The desired salinity level (15 dS m⁻¹) was developed by mixing required amount of NaCl in the soil before filling the pots. Waterlogging was developed by flooding the pots for 21 days both at tillering and booting stages. Compaction significantly reduced the root length density (RLD) of both the wheat genotypes while the combined effect of compaction×salinity was more drastic on root length density than compaction alone. Waterlogging however, did not decrease the root length density, rather it mitigated the effect of compaction. Compaction decreased the concentration of K⁺ and K⁺:Na⁺ ratio in leaves. Salinity also decreased the concentration of K⁺ and K⁺:Na⁺ ratio, but increased the concentrations of Na⁺ and Cl⁻ in the crop leaves. Salinity and compaction interacted to cause a greater reduction in K⁺ concentration and the K⁺:Na⁺ ratio, while there was lesser increase in the concentrations of Na⁺ and Cl⁻ compared with salinity alone. Waterlogging also decreased the concentration of K⁺ and K⁺:Na⁺ ratio in leaves. It intensified the effect of salinity but decreased the effect of compaction on leaf ionic composition. Therefore, the effect of compaction on root growth and ion uptake is more severe under salt-affected soil conditions than under normal soil conditions while occasional waterlogging of a compact soil for a few days makes the soil conditions favorable for root growth both under non-saline as well as saline soil conditions. Also, the performance of a genotype in stressed environment is related to maintenance of higher root length density, leaf K⁺ concentration and K⁺:Na⁺ ratio and lower leaf Na⁺ and Cl⁻ concentrations.     

油菜湿害及其防治措施研究进展

油菜是我国四大油料作物之一,湿害威胁中国的油菜生产。文章综述了湿害对油菜生长发育的危害和生理生化的影响,从育种和栽培2个方面提出的改善油菜耐湿性的方法。     

开花期渍水对小麦产量及氮素分配的影响

为探究江汉平原小麦生育期间雨水过多对小麦造成的影响,于2020-2021年以耐渍品种襄麦55和主推品种郑麦9023为供试材料开展大田试验,分析了开花期连续渍水7 d小麦产量、干物质和氮素积累与转运的变化。结果表明,与无渍水的对照（CK）相比,渍水导致小麦旗叶SPAD值下降。渍水后郑麦9023旗叶比襄麦55衰老更早,旗叶功能期相对更短。开花期渍水致使成熟期营养器官干物质和氮素积累量下降,促进花前储存的干物质和氮素在花后向籽粒的转运,提高了花前储存的干物质和氮素对籽粒产量和氮素的贡献率,但依然使成熟期单茎籽粒干物质和氮素积累量分别下降10.87%~13.59%和19.32%~23.60%。襄麦55成熟期茎鞘的干物质和氮素积累量下降量较大,花前干物质和氮素转运效率高于郑麦9023。开花期渍水影响籽粒灌浆速率和灌浆时间。渍水导致襄麦55最快灌浆期由花后21~35 d缩短至花后28~35 d,但单粒重下降不显著;渍水后郑麦9023灌浆在花后35 d时基本停止,单粒重下降显著。开花期渍水显著降低小麦产量,使襄麦55和郑麦9023分别减产7.7%和15.6%,减产主因分别是穗粒数和千粒重的显著下降。总之,开花期渍水会导致小麦减产,但促进了花前储存的干物质和氮素向籽粒的转运,对襄麦55花前干物质和氮素转运的影响大于郑麦9023。     

花后渍水和高温对小麦旗叶光合特性、干物质积累及产量的影响

为了解花后渍水和高温对小麦旗叶光合特性、干物质积累与分配和产量的影响,以扬麦18和烟农19为试验材料,采用盆栽法,在小麦开花期设置渍水(WL)、高温(HL)和渍水+高温复合胁迫(WL+HL)处理,以正常生长为对照(CK),测定并分析了不同处理下小麦旗叶光合指标、干物质积累量、产量及其差异。结果表明,与CK比较,花后渍水、高温、渍水+高温胁迫均显著降低了2小麦品种旗叶的SPAD值、净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)、最大光化学效率(F_v/F_m)、实际光化学效率Ф_PSⅡ,增加了胞间CO₂浓度(C_i)。花后渍水、高温、渍水+高温胁迫处理较CK降低了成熟期各器官干物质积累量及籽粒占总干物质积累量的比例,提高了营养器官所占比例;显著降低了小麦穗粒数、千粒重和产量。渍水+高温复合胁迫对光合指标、干物质积累量以及产量的影响程度明显大于渍水和高温单一因素,高温对其影响大于渍水。在花后21d时,被测光合参数(除...     

棉花遭受涝渍胁迫后的快速恢复技术

[目的]研究棉花苗期遭受涝渍胁迫后,采用不同的恢复技术对棉花形态、生理和产量及其构成因子的影响,为遭受涝渍胁迫后的棉花快速恢复提供理论参考。[方法]采用盆栽方法,以湘杂棉8号F1、中棉所63F1为试验材料,淹水15 d排除渍水后进行恢复,设置双对照,共13个处理。研究采用恢复技术后棉花形态生长、SPAD、产量、棉铃等特征变化。[结果]涝渍胁迫后采用恢复技术能加快棉花株高及叶片增长。喷施天丰素、尿素及磷酸二氢钾等技术能提高主茎功能叶叶绿素含量。喷施萘乙酸、赤霉素、乙烯利、尿素加磷酸二氢钾,土壤穴施复合肥,土壤穴施复合肥配合喷施尿素加磷酸二氢钾等恢复技术均能提高单株地上部分干物质积累量及总干物质积累量,其中总干物质积累量提高最大的技术为土壤穴施,分别比胁迫不采用恢复技术处理总干物质积累量提高45.2%、70.4%;总干物质积累量恢复到不受涝渍胁迫处理的54.1%、58.2%。对籽棉产量分析,植株喷施尿素加磷酸二氢钾、土壤穴施氮磷钾复合肥2项技术,与涝渍胁迫不采用恢复技术对照比较均达极显著差异,其中植株喷施尿素加磷酸二氢钾技术比涝渍胁迫不采用恢复技术对照提高94.9%、144.5%,恢复到未受涝渍胁迫对照的71.3%、73.6%。[结论]通过试验数据分析,棉花苗期遭受涝渍胁迫后,喷施尿素加磷酸二氢钾、土壤穴施复合肥均能快速恢复棉花生长。     

不同淹水程度对棉花苗期生长及生理变化的影响

为了明确棉花遭受涝害胁迫后的适应能力,采用盆栽种植方式,在避雨棚内对苗期棉株进行淹水;研究不同淹水程度下棉花形态、产物及生理变化。结果表明,淹水后棉花产量、单株成铃率、单铃重、株高、叶片数、单株干物质积累量都将减少,而衣分没有变化;随着淹水时间的增加,各指标将进一步降低,淹水20d后,叶片SPAD值急剧下降,皮棉产量减少了80%以上,基本绝收。综合分析,淹水15d可以认为是棉花苗期适应涝害胁迫的临界时间,在此之前棉花可以通过栽培技术措施进行补救,恢复生长。     

芝麻对涝害的反应及适应性变异Ⅰ. 模拟涝害胁迫下芝麻基因型间的形态、生物量及产量变化

采用双因素裂区设计,在大田人工淹水条件下研究了5种芝麻基因型对渍害的适应性反应。结果表明,心叶缺铁性黄化,新生根产生,生物量及籽粒产量下降,植株茎延伸生长为典型的渍水胁迫症状;芝麻对渍水敏感期为初花期,生育早期渍水驯化能显著改善芝麻的耐渍性。基因型间,野芝7号耐渍性最强,心叶黄化不明显,新生白根数多,产量损失很小,相对产量为0．967,生物量下降后恢复能力强。豫芝1号、武昌九根头新生白根较多,生物量下降后有较强的恢复能力,相对产量较低,分别为0．428和0．626,耐渍性较好。丹巴格心叶黄化较明显,白根量少,生物量能部分恢复,相对产量0．813,具中度耐渍性。遂平小籽黄心叶黄化快,基本无白根发生,产量损失大,相对产量0．338,耐渍性差。     

Interactive Effects of Elevated Atmospheric CO2 and Waterlogging on Vegetative Growth of Soybean (Glycine max (L.) Merr.)

Abstract

Waterlogging is a major predicted agricultural problem for crop production in some areas under current climate change, but no studies are available on the interactive effects of waterlogging and elevated atmospheric CO₂ concentration ([CO₂]). We hypothesized that elevated [CO₂] could alleviate the damage caused by waterlogging, and tested the hypothesis using vegetative growth of soybean (Glycine max) in 10 experiments (different sowing time and different soil type) conducted at Morioka and Tsukuba for three years. The 2-week-old plants grown under elevated and ambient [CO₂] were exposed to waterlogging for 2 weeks. Total dry weight at the end of the treatment was higher under elevated [CO₂] than under ambient [CO₂], and it was significantly reduced by waterlogging under both levels of [CO₂], without significant [CO₂]×waterlogging interactions, at both locations. The negative effects of the waterlogging were greater in root dry weight than in top dry weight, and the root exudation per unit root dry weight was also reduced by waterlogging, without a [CO₂] ×waterlogging interaction. Therefore, the hypothesis of a [CO₂]×waterlogging interaction can be rejected, and provide an important basis for predicting future damage caused by waterlogging under elevated [CO₂] conditions.     

水分胁迫下水杨酸对毛豆幼苗生长及其抗渍性的影响

在水分胁迫下采用不同浓度的水杨酸对毛豆幼苗进行叶面喷施处理，测定其对毛豆幼苗生长及其抗渍性的影响。试验结果表明：采用一定浓度的水杨酸处理可以促进苗生长、提高根系活力、叶绿素含量、脯氨酸含量和抑制丙二醛增生、降低细胞膜透性，增强了毛豆幼苗对渍水环境的抵抗能力。从叶面喷施对毛豆的营养指标和生理指标进行综合判断可知：在试验的范围内，以2mmol/L水杨酸的处理效果为最佳。     

小麦水分胁迫影响因子的定量研究 Ⅱ.模型的建立与测试

基于冬小麦水分生理生态关系，综合考虑土壤水分有效性、作物不同生育阶段对干旱或渍水胁迫的敏感性、作物主要生理过程（蒸腾、光合作用、干物质分配等）对干旱胁迫的差异性、渍水持续天数等确定了支持作物生长模拟的干旱和渍水胁迫影响因子的算法。用独立于建模的盆栽小麦水分试验观测资料对干旱和渍水胁迫影响因子的算法进