【作者】 陈晓光；

【导师】 王振林；

【作者基本信息】 山东农业大学 ， 作物栽培学与耕作学， 2011， 博士

【摘要】 本研究选用抗倒性不同的6个小麦品种,通过设置不同种植密度、氮肥施用量和喷施多效唑等栽培措施,于2008年～2010年系统研究了小麦茎秆形态特征、解剖结构特征和茎秆理化特性及其抗倒伏能力的变化,分析了不同抗倒伏能力小麦茎秆特征的品种差异,探讨了种植密度、氮肥和多效唑对小麦抗倒伏能力的影响及其生理生化机理。主要研究结果如下:1小麦抗倒伏性的品种差异1.1不同抗倒伏能力小麦品种茎秆形态特征与抗倒伏能力较差的小麦品种(藁城8901和烟农21)相比,抗倒伏能力强的小麦品种(济麦20和济麦22)的株高、重心高度、基部节间长度和基部(1+2)节间占总茎长的比例、内径厚度和茎秆干物质转移率均明显降低,而外径厚度、茎秆鲜、干质量增加。相关分析表明,小麦实际倒伏率与基部第2节间外径大小、壁厚和茎秆充实度呈显著负相关,与株高、重心高度和基部节间长度呈显著正相关。在小麦实际生产中,茎秆基部节间株高和重心高度较低、内径小、茎壁较厚、干物质转移率低和节间充实度高是小麦茎秆抗倒伏能力强的具体体现。1.2不同抗倒伏能力小麦品种茎秆解剖结构特征通过对抗倒伏能力不同的6个小麦品种茎秆基部第2节间的解剖结构研究显示,小麦茎秆抗倒伏能力强的品种(济麦20和济麦22),其茎秆壁厚,机械组织细胞层数多而厚,大维管束数目多且面积大;抗倒伏能力较弱的品种(藁城8901和烟农21),其基部茎秆机械组织细胞层数较少且薄,大维管束数目少且面积小。相关分析表明,基部第2节间机械组织层数和厚度、大维管束数目和面积与小麦实际倒伏率均呈显著或极显著负相关。小麦茎秆基部第2节间机械组织层数多、茎壁厚、大维管束数目多且面积大,这些特征可能是选育抗倒伏小麦品种的重要指标。1.3不同抗倒伏能力小麦品种茎秆理化特性茎秆的理化特性与其抗倒性密切相关。茎秆中可溶性总糖及钾、氮的含量和基部节间抗折力对茎秆基部节间的抗倒伏指数和实际倒伏率均有显著影响。小麦实际倒伏率与其倒伏指数、基部抗折力、可溶性总糖和钾含量显著负相关,与基部节间氮含量显著正相关。不同小麦品种的茎秆木质素含量也存在明显差异。茎秆抗折力大、倒伏指数小的品种(济麦20和济麦22),其茎秆木质素含量高,苯丙氨酸转氨酶(PAL)、肉桂醇脱氢酶(CAD)、酪氨酸解氨酶(TAL)和4-香豆酸:CoA连接酶(4CL)活性强。相关分析表明,茎秆木质素含量与实际倒伏率呈显著负相关(r = -0.83, P<0.05);与抗折力呈显著正相关(r =0.86, P<0.05);PAL、TAL和CAD活性与木质素含量呈显著正相关(r =0.78、0.77、0.85, P<0.05),4CL活性与木质素含量呈不显著正相关(r =0.39, P>0.05)。研究表明,较高的PAL和CAD活性是木质素含量高的酶学基础,茎秆木质素含量可作为小麦品种抗倒伏性评价的一个重要指标。2栽培措施对小麦抗倒伏性的调控2.1种植密度与小麦抗倒伏性的关系随种植密度的增加,小麦茎秆高度和重心高度升高,茎秆基部节间变细长,茎壁变薄,基部第(1+2)节间占总长的比例增大,基部节间比茎重降低,小麦倒伏现象严重。说明在小麦生产中,增加种植密度使株高增高、节间充实度降低是造成小麦倒伏的重要原因之一。随种植密度的增加,烟农21和藁城8901的基部第2节间机械组织层数减少、茎壁厚度降低,大维管束数目和面积也有不同程度的降低。采用合理的种植密度,建立合理的群体结构,促进茎秆机械组织发育,增加大维管束数目和面积,是实现壮秆,为高产抗倒群体的建立打下良好基础的前提。增加种植密度在一定程度上降低了基部茎秆中氮、钾元素含量,并降低基部节间茎秆中可溶性总糖和淀粉含量,进而影响基部茎秆的抗折力和抗倒伏指数。增加种植密度使基部第2节间中的木质素含量及其合成相关酶(PAL、TAL、4CL和CAD)活性明显降低,进而导致小麦茎秆抗倒伏能力下降。2.2氮肥和多效唑与小麦抗倒伏性的关系氮肥施用量显著影响小麦茎秆抗倒伏能力。与低施氮(225 kg·hm-2)处理相比,高施氮(300 kg·hm-2)处理的茎秆高度、基部节间长度和基部(1+2)节间占总茎长的比例均增加,而基部节间粗度、节间充实度降低。喷施多效唑后,小麦基部节间缩短,基部第(1+2)节间占总茎长的比例降低,基部茎增粗,茎壁增厚,茎秆高度降低,重心位置下移,基部茎秆单位长度内干物质重量提高,小麦的抗倒伏能力增强。表明起身期叶面喷洒多效唑,对于解决高产麦田生育后期倒伏问题具有重要意义。与低施氮(225 kg·hm-2)处理相比,高施氮(300 kg·hm-2)处理使茎秆基部第2节间机械组织细胞层数减少,厚度变薄,大维管束数目和面积也减小。喷施多效唑使小麦茎秆基部第2节间的维管束数目和面积增加,机械组织层数增多,厚度增厚,小麦抗倒伏能力增强。与低施氮(225 kg·hm-2)处理相比,高施氮(300 kg·hm-2)处理降低了茎秆基部节间中可溶性总糖、淀粉和钾含量,而氮含量增加,氮/钾比值增大,导致基部茎秆抗折力和抗倒伏指数下降,增加倒伏风险。喷施多效唑则增加了茎秆基部节间氮、钾含量,增加了淀粉和可溶性总糖含量,提高了基部茎秆抗折力和抗倒伏指数,减少倒伏面积。同品种条件下,与低施氮(225 kg·hm-2)处理相比,高施氮(300 kg·hm-2)处理降低了茎秆PAL、TAL、CAD和4CL的活性,茎秆木质素含量、抗折力和抗倒伏指数降低。而喷施多效唑显著提高茎秆PAL、TAL和CAD的活性,木质素含量、茎秆抗折力和抗倒伏指数提高,倒伏面积和倒伏程度降低。相关分析表明,茎秆抗倒伏指数与木质素含量呈显著正相关(R=0.61,P<0.05);木质素含量与PAL、TAL和CAD酶活性呈显著正相关,与4CL酶活性相关不显著。高施氮量处理降低了茎秆木质素合成相关酶的活性和木质素含量,茎秆抗倒伏能力降低。施用多效唑显著提高茎秆木质素合成相关酶的活性和木质素含量,进而增强了茎秆抗倒伏能力,这是施用多效唑增强小麦抗倒伏性的生理机制之一。更多还原

【Abstract】 Six wheat varieties with different lodging resistances were grown at Tai’an Experimental Station of Shandong Agriculture University during the 2008~2010 growing seasons. The studies were focused on stem morphological characteristics, anatomical structure feature and physicochemical properties as well as the changes of stem lodging resistance, and the result elucidated the relationship between lodging and the character of culm. This research analyzed the variety differences of stem characteristics with different lodging resistance, discussed the physiological and biochemical mechanism of planting density, nitrogen and paclobutrazol on lodging resistance of wheat. The main results were as follows:1 Difference of variety in the lodging resistance of wheatThe field experiments were carried out at Tai’an Experimental Station of Shandong Agricultural University in two growing seasons from October 2008 to June 2009 and from October 2009 to June 2010. Six wheat cultivars (Triticum aestivum L.), JM 20 and JM 22 (high lodging resistance of wheat), and Gaocheng 8901 and Yannong21 (middle lodging resistance of wheat), and Youzimai and Pingyuan 50 (low lodging resistance of wheat) were employed in this study.1.1 Stem morphological characteristics with different lodging resistance of wheatCompared with middle lodging resistance of wheat varieties (Gaocheng 8901 and Yannong 21), the plant height, ratio of gravity center height to plant height, basal internodes length and percentage of basal internode(1+2) length in the total stem length, inner diameter and dry matter transfer rate high lodging resistance of wheat varieties (Jimai 20 and Jimai 22) significantly reduced, while outer diameter, stem fresh and dry weight incresased. Correlation analysis showed that there was siginificantly negative correlation between the actal lodging percentage and the diameter thickness of basal internode and filling degree, while there was a significantly positive correlation between plant height, ratio of gravity height and length of basal. In wheat production, shorter basal internodes, lower plant height, smaller inner diameter, thicker stem diameter, higher filling degree of stem, lower the dry matter tranfer rate were significant characteristics of high lodging resistance of wheat.1.2 Anatomical structure features with different lodging resistance of wheatBy analyzing the anatomical structure of the 2nd basal internode of the six lodging resistance of different varieties, the result showed that wheat varieties with high lodging resistance (Jimai 20 and Jimai22) had wall thickness and more mechanical tissue cell layer, the large vascular bundles tended longer, wider and had more numbers. Varieties with low lodging resistance (Youzi wheat and Pinyuan 50), the mechanical tissue cell layers was less and thinner, the large vascular bundle tended shorter, narrower and lesser numbers. Correlation analysis showed that the layer and thickness of the mechanical tissue of the 2nd basal internodes and the large vascular bundle number and area had significant or very significant negative correlation with the lodging rate of wheat. The results indicated that for good quality culm, the mechanical tissue had more cell layers; the large vascular bundles tended longer, winder and had more numbers; the wall of culm was thicker.1.3 Physical and chemical characteristic with different lodging resistance of wheatThe physical and chemical characteristics of culm were closely related with its lodging resistance. The content of soluble sugar and potassium, nitrogen content, snapping resistance of the basal internodes had the greater effect on the lodging resistance of basal internodes and actual lodging percentage. The actual lodging percentage of wheat were significant negative correlation with the lodging index, snapping resistance of the basal internodes, the content of soluble sugar and potassium, and nitrogen content was significant positive correlation. The lignin content and activities of phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), cinnamyl alcohol dehydrogenase (CAD), and 4-coumarate:CoA ligase (4CL) were tested in the second internode of six cultivars with different lodging resistance. The snapping resistance and culm lodging index were determined at anthesis, milking, and maturity stages. The lignin content varied significantly among cultivars. Jimai 22 and Jimai 20, which showed high resistance to culm snapping and loging, had higher lignin content and the activities of PAL, TAL, CAD, and 4CL than other cultivars. The lignin content was negatively correlated with the actual lodging ratio (r =-0.83, P<0.05), and positively correlated with the snapping resistance of culm (r =0.86, P<0.05). The activities of PAL, TAL, and CAD were positively correlated with lignin content with correlation coefficients of 0.78 (P<0.05), 0.77 (P<0.05) and 0.85 (P<0.05), respectively. Based on these results, we conclude that high activities of PAL and CAD are the enzymatic basis of increased lignin content, and the lignin content in culm can be used as an important indicator to evaluate lodging resistance of wheat.2 Regulation of cultivation measures on the lodging resistance of wheat2.1 Relationship between planting density and lodging resistance of wheatWith the increase of planting density, plant height and ratio of gravity center height to plant height were incresed, basal internodes tended slender and thinner, percentage of basal internode(1+2) length were improved, weight percentage of basal internodes was significantly reduced, and lead to serious lodging of wheat. The plant height was heightened and the filling degree of internode was decreased with the increase of planting density, and this was a main cause lodging of wheat.With the increase of planting density, the mechanical tissue layer of the 2nd internodes of Yannong 21 and Gaocheng 8901 reduced, stem wall thickness decreased, the large vascular bundle number and area had different degrees of reduction. Adopting rational planting density to establish a rational structure, to promote development of the mechanical tissue of stem as well as the area and amount of the large vascular bundle were premise of realizing sound seedling and lay a good foundation to build a population structure of lodging resistance.The nitrogen and potassium element content, the souble sugar and starch content of basal internodes, the snapping resistance and lodging resistance index were redued with the increase of the planting desity. The culm lodging resistance index was positively correlated with the plant density.The lignin content of the second basal internode and PAL, TAL, 4CL and CAD activities were significantly reduced with the increase of the planting density, which led to the lowring of wheat stem.2.2 Relationship between nitrogen and paclobutrazol and lodging resistance of wheatNitrogenous significantly influenced the lodging resistance of wheat. Compared with low N (225 kg·hm-2) rate, the plant height and percentage of basal internode(1+2) length of total internode length of the plant high N (300 kg·hm-2) rate were increased, but the thickness and filling degree of basal internodes were decreased. After spraying paclobutrazol, the basal internodes of wheat shortened and percentage of basal internode(1+2) length of the plant decreased, outside diameter and wall thickness of culm increased, ratio of gravity center height to plant height were lowers, ratio weight to lenghth of stem were increased, wheat lodging resistance were enhanced. The result showed that spraying paclobutrazol had great effect on solving the lodging problems during growth later stage of high-yielding wheat.Compared with low N(225 kg·hm-2) rate, the high N(300 kg·hm-2) rate made mechanical tissue cell layers decreased and becomed thinner, the amount and area of big vascular bundles and area also decreased. Spraying paclobutrazol caused the amount and area of the second internodes increased and the mechanical tissue cell layers increased and becomed thicker. And the lodging resistance was enhanced.Compared with low nitrogen N(225 kg·hm-2) rate, the high N(300 kg·hm-2) rate made soluble sugar, starch and potassium content lower and nitrogen content increased, nitrogen potassium ratio increased, lead to the decrease of snapping resistance and lodging resistance index and increased the risk of lodging. Spraying paclobutrazol increased contents of nitrogen and potassium of basal internodes, increased starch and soluble sugar content, and improved the snapping resistance and lodging resistance index and decreased lodging area.Compared with the low N(225 kg·hm-2) rate, the high N(300 kg·hm-2) rate reduced the PAL, TAL, CAD and 4CL activities and lignin content, reduced snapping resistance and CLRI under the same cultivar condition. The application of PP333 improved the PAL, TAL and CAD activities, increased lignin content, snapping resistance and CLRI, thus reduced lodging area and lodging degree. Correlation analysis showed that the lignin content of basal stem had a significant and positive correlation with PAL, CAL and CAD activity and CLRI, respectively, yet had no significant correlation with 4CL activity. The high N(300 kg·hm-2) rate reduced the PAL, TAL,CAD enzyme activities and lodging resistance. Spaying PP333 improved the PAL, TAL, CAD enzyme activities and lignin content, and thus enhanced the lodging resistance.更多还原