高效利用土壤磷素的植物营养学研究

论述磷在农业及生态系统中的重要地位,磷资源的危机以及磷土壤中的理化特性,探讨土壤的供磷潜力,不同植物品种以及相同品种不同基因型对土壤潜在磷资源的吸收利用差异,营养机制,遗传特性及其利用不同作物的基因型来活化,吸收利用土壤难溶态磷的可行性对策,从而为充分发挥植物自身潜力,提高土壤难溶态磷的生物有效性,高效利用土壤潜在磷资源,加快土壤磷素有效循环,节省资源,保护环境,真正达到生态系统的稳定与现代化农业     

不同基因型春小麦对磷胁迫适应性研究

采用盆栽试验,测定了4种基因型春小麦在不同生育期,3种磷水平下植株体内酸性磷酸酶活性、根长、根半径、根干重、根冠比、地上部干重、产量等指标,研究了小麦生长对磷素的利用效率。结果表明：甘春20号对磷素的敏感性在酸性磷酸酶活性、根干重、地上部干重、增产潜力均强于陇春16号、会宁18号和定西33号,是磷高效基因型;高磷对陇春16号的根冠比和根干重影响显著,定西33号和会宁18号的根长较长,因此陇春16号、会宁18号和定西33号仍具有一定的磷素利用潜势。     

小麦磷素利用效率的品种差异

通过土培盆栽试验,研究了小麦不同品种在低磷水平下生物量、磷浓度、磷素干物质生产效率及磷素籽粒生产效率的差异,以筛选磷高效利用小麦品种.结果表明：分蘖期、拔节期、扬花期和成熟期,供试小麦品种单株生物量的变幅分别为0.46～1.09、0.85～2.10、3.00～7.00和3.85～12.88 g,磷浓度变幅分别为2.21～4.26、2.38～4.42、2.44～4.96和1.30～5.09 mg·g^-1.随生育时期的推进,小麦磷素累积量、磷素干物质生产效率对生物量形成的影响程度呈减小趋势.分蘖期（CV=16.3%）、拔节期（CV=15.0%）、扬花期磷素干物质生产效率（CV=13.3%）和成熟期磷素籽粒生产效率（CV=20.5%）的品种差异较大.CD1158-7和省A3宜03-4具有较高的磷素干物质生产效率和磷素籽粒生产效率,而渝02321较低;不同生育时期高效品种磷浓度极显著低于低效品种,而高效品种CD1158-7和省A3宜03-4的籽粒产量分别是低效品种渝02321的1.98和1.78倍.     

磷高效基因型小麦对缺磷胁迫的根际适应性反应

采用奶箱分隔栽培试验法,进行了磷高效与磷低效小麦基因型根际土壤ＰＨ与有效磷变化的研究,结果表明：小麦根际土壤ＰＨ和有效磷含量皆明显低于外围土壤,表现出明显的根际效应特征;磷高效基因型小麦的根际ＰＨ和有效磷含量明显低于磷低效基因型,ＰＨ变异范围和磷素亏缺区也表现明显较大。为了进一步验证磷高效小麦基因型这的这一根际特征,同时进行了施用水溶性,枸溶性磷肥的试验研究,结果表明,以水溶性磷肥对根际ＰＨ和有效     

不同基因型小麦幼苗抗旱抗盐性比较研究

利用等渗的NaCl和PEG处理8种不同基因型小麦进化材料,在处理的3d,6d,9d分别采样测定叶片相对含水量,胁迫敏感指数,游离脯氨酸,可溶性糖,无机离子Na^ ,K^ 含量及荧光参数Fv/m生理指标等。结果表明;在相同渗透势胁迫下,NaCl胁迫引起的小麦叶片荧光参数Fv/m的下降;胁迫敏感指数,脯氨酸,可溶性糖,Na^ 含量的增加均大于PEG胁迫引起的变化,而叶片相对含水量的K^ 含量的下降却小于PEG胁迫下的变化,含有DD染色体组的2n小麦较含有BB和AA的2n小麦有较强的抗旱抗盐性,且由它与4n小麦（AABB）杂交合成的6n小麦（AABBDD）较2n和4n小麦有较强的抗旱抗盐性,且由它与4n小麦（AABB）杂交合成的6n小麦（AABBDD）较2n和4n小麦有较强的抗旱抗盐性,说明DD染色体组上具有控制小麦抗旱和抗盐的有效基因。     

不同基因型小麦花药培养过程中药壁变化的研究

在相同的培养条件下 ,比较了不同基因型小麦花药培养过程中药壁变化的差异。组织切片观察表明 :易诱导材料花药培养过程中 ,药壁细胞发育充实 ,活力强 ,降解衰退较难诱导材料有所延缓 ;两种材料的花药刚离体时绒毡层就存在着明显的差异     

小麦不同基因型材料花药培养中雄核发育的研究

对小麦离体花药中花粉发育的调查表明 :难诱导材料花药在培养初期 ,花粉退化快 ,大量小孢子败育 ,多细胞 (核 )花粉出现晚、频率低 ;而易诱导材料花药培养初期 ,花粉退化相对延缓 ,多细胞 (核 )花粉出现早且频率高 ,这些内在的优势使得更多的小孢子有可能转向孢子体发育 ,从而获得较高的出愈率。     

不同基因型小麦花药培养过程中药壁变化的研究

在相同的培养条件下,比较了不同基因型小麦花药培养过程中药壁变化的差异。组织切片观察表明：易诱导材料花药培养过程中,药壁细胞发育充实,活力强,降解衰退较难诱导材料有所延缓;两种材料的花药刚离体时绒毡层就存在着明显的差异。     

小麦不同基因型材料花药培养中雄核发育的研究

对小麦离体花药中花粉发育的调查表明：难诱导材料花药在培养初期,花粉退化快,大量小孢子败育,多细胞(核)花粉出现晚、频率低;而易诱导材料花药培养初期,花粉退化相对延缓,多细胞(核)花粉出现早且频率高,这些内在的优势使得更多的小孢子有可能转向孢子体发育,从而获得较高的出愈率。     

水稻苗期磷高效基因型筛选研究

采用难溶性磷酸盐Ca3 (PO4) 2 为唯一磷源 ,在pH值为 5 .5条件下产生相对高浓度低磷胁迫及以NaH2 PO4为磷源配制P浓度为 0 .5mg·L-1的相对低浓度低磷胁迫的两个水培环境 ,分别对不同基因型水稻的磷效率进行评价 .以相对分蘖干重 (RTW )、相对总生物量 (RPW )、相对分蘖数 (RTN)、相对根系干重(RRW )、相对地上部干重 (RSW )、相对叶龄 (RLA)和相对株高 (RPH)作为耐性指标进行相关分析 .结果表明 ,供试材料的磷效率存在极显著差异 ,若以能产生分蘖的相对高浓度低磷胁迫进行筛选时 ,相对分蘖干重、相对地上部干重、相对总生物量可作为较好的筛选指标 ,其中相对分蘖干重不仅与其它指标间的相关性强 ,且品种间差异和变异系数均较大 ,能准确、灵敏地反映不同基因型间的耐低磷胁迫能力 ;若采用相对低浓度的低磷胁迫对不同基因型水稻进行耐低磷种质筛选时 ,筛选指标则不同 ,最好的单一筛选指标应是相对地上部干重或相对总生物量 .     

Dry matter production and distribution of zinc in bread and durum wheat genotypes differing in zinc efficiency

Six bread wheat (Triticum aestivum cvs. Kiraç-66, Gerek-79, Aroona, ES 91-12, ES-14 and Kirkpinar) and four durum wheat (Triticum durum cvs. BDMM-19, Kunduru-1149, Kiziltan-91 and Durati) genotypes were grown under controlled environmental conditions in nutrient solution for 20 days to study the effect of varied supply of Zn (0 to 1 µM) on Zn deficiency symptoms in shoots, root and shoot dry matter production, and distribution of Zn in roots and shoots.Visual Zn deficiency symptoms, such as whitish-brown lesions on leaves, appeared rapidly and severly in durum wheats, particularly in Kiziltan-91 and Durati. Among the durum wheats, BDMM-19 was less affected by Zn deficiency, and among the bread wheats Kiraç-66, ES 91-12, Aroona and Gerek-79 were less affected than ES-14 and Kirkpinar.Under Zn deficiency, shoot dry matter production was decreased in all genotypes, but more distinctly in durum wheat genotypes. Despite severe decreases in shoot growth, root growth of all genotypes was either not affected or even increased by Zn deficiency. Correspondingly, shoot/root dry weight ratios were lower in Zn-deficient than in Zn-sufficient plants, especially in durum wheat genotypes.The distinct differences among the genotypes in sensitivity to Zn deficiency were closely related with the Zn content (Zn accumulation) per shoot but not with the Zn concentration in the shoot dry matter. On average, genotypes with lesser deficiency symptoms contained about 42% more Zn per shoot than genotypes with severe deficiency symptoms. In contrast to shoots, the Zn content in roots did not differ between genotypes. Shoot/root ratios of total Zn content were therefore greater for genotypes with lesser deficiency symptoms than for genotypes with severe deficiency symptoms (i.e. all durum wheat genotypes).The results suggest that the enhanced capacity of genotypes for Zn uptake and translocation from roots to shoot meristems under deficient Zn supply might be the most important factor contributing to Zn efficiency in wheat genotypes. The results also demonstrate that under severe Zn deficiency, Zn concentration in the shoot dry matter is not a suitable parameter for distinguishing wheat genotypes in their sensitivity to Zn deficiency.     

Variation in phosphorus efficiency among 73 bread and durum wheat genotypes grown in a phosphorus-deficient calcareous soil

A greenhouse experiment was carried out to study the severity of phosphorus (P) deficiency symptoms on leaves, shoot dry matter production, and shoot concentration and content (the total amount per shoot) of P in 39 bread wheat (Triticum aestivum L.) and 34 durum wheat (Triticum durum L.) genotypes grown in a severely P-deficient calcareous soil with low (20mgPkg⁻¹ soil) and adequate (80mgPkg⁻¹ soil) P supply for 39 days. As the seed P concentration or content can affect plant performance under P-deficient conditions, the seeds of the genotypes used in the present study were also analyzed for P concentration. Phosphorus efficiency (relative shoot growth) of genotypes, calculated by the ratio of shoot dry matter production under low P to that under adequate P supply, significantly differed among the genotypes, and varied between 46.7% and 78.6%. Phosphorus efficiency ranged from 51% to 71% with an average of 61% for bread and from 47% to 79% with an average of 66% for durum wheat genotypes. There was no correlation between P efficiency ratio and P concentration of plants (R ²=0.0001), but P efficiency of all bread and durum wheat genotypes showed a very significant correlation with the P content (the total amount of P per shoot) (R ²=0.333^***). The relationship between the P efficiency and total amount of P per shoot was much more significant in bread (R ²=0.341^***) than in durum wheat (R ²=0.135^*). Like shoot P concentrations, also severity of visible leaf symptoms of P deficiency on older leaves, including leaf chlorosis and necrosis, did not correlate with P efficiency. In most cases, genotypes showing higher P efficiency had higher absolute shoot dry weight under P deficient conditions. Under P deficient conditions, the absolute shoot dry weight very significantly correlated with shoot P content (R ²=0.665^***), but the correlation between the absolute shoot dry weight and shoot P concentration tended to be negative. There was also variation in native seed P reserve of the genotypes, but this variation had no influence on the P efficiency. The results indicate that the total amount of P per shoot and shoot dry matter production at low P supply are most reliable parameters in ranking genotypes for P efficiency at early growth stage. In wheat germplasm tested in the present study, several wheat genotypes are available showing both very high P efficiency and very high shoot content and concentration of P suggesting that P acquisition ability should be most important mechanism for high P efficiency in such genotypes. On the other hand, there are also genotypes in the germplasm having more or less same P concentration or P content in shoot but differing substantially in P efficiency, indicating importance of P utilization at cellular level in P efficiency. All these results suggest that P efficiency mechanisms can be different from one genotype to other within a given plant species.     

Phytosiderophore release in bread and durum wheat genotypes differing in zinc efficiency

The effect of the zinc (Zn) nutritional status on the rate of phytosiderophore release was studied in nutrient solution over 20 days in four bread wheat (Triticum aestivum cvs. Kiraç-66, Gerek-79, Aroona and Kirkpinar) and four durum wheat (Triticum durum cvs. BDMM-19, Kunduru-1149, Kiziltan-91 and Durati) genotypes differing in Zn efficiency.Visual Zn deficiency symptoms, such as whitish-brown necrosis on leaves and reduction in plant height appeared first and more severe in Zn-inefficient durum wheat genotypes Kiziltan-91, Durati and Kunduru-1149. Compared to the bread wheat genotypes, all durum wheat genotypes were more sensitive to Zn deficiency. BDMM-19 was the least affected durum wheat genotype. Among the bread wheat genotypes, Kirkpinar was the most sensitive genotype. In all genotypes well supplied with Zn, the rate of phytosiderophore release was very low and did not exceed 1 mol 32 plants^-1 3h^-1, or 0.5 mol g^-1 root dry wt 3h^-1. However, under Zn deficiency, with the onset of visual Zn deficiency symptoms, the release of phytosiderophores was enhanced in bread wheat genotypes up to 7.5 mol 32 plants^-1 3h^-1, or 9 mol g^-1 root dry wt 3h^-1, particularly in Zn-efficient Kiraç-66, Gerek-79 and Aroona. In contrast to bread wheat genotypes, phytosiderophore release in Zn-deficient durum wheat genotypes remained at a very low rate. Among the durum wheat genotypes BDMM-19 had highest rate of phytosiderophore release. HPLC analysis of root exudates showed that 2-deoxymugineic acid (DMA) is the dominating phytosiderophore released from roots of Zn-efficient genotypes. In root extracts concentration of DMA was also much higher in Zn-efficient than in inefficient genotypes. The results demonstrate that enhanced synthesis and release of phytosiderophores at deficient Zn supply is involved in Zn efficiency in wheat genotypes. It is suggested that the expression of Zn efficiency mechanism is causally related to phytosiderophore-mediated enhanced mobilization of Zn from sparingly soluble Zn pools and from adsorption sites, both in the rhizosphere and plants.     

Variation in acquisition of soil phosphorus among wheat and barley genotypes

To assess the extent of variation in phosphorus acquisition efficiency of some winter wheat (Triticum aestivum L.), winter and spring barley (Hordeum vulgare L.) genotypes, depletion of inorganic phosphorus (P) extractable with 0.5 M NaHCO₃ (NaHCO₃-P_i) from the rhizosphere soil was studied. Nutrients supply, rhizosphere soil pH and soil water content was kept equal for all the genotypes with the aim to reduce the confounding variation due to these factors. The experimental set up implied that no difference in the relative growth rates, nitrogen, potassium and calcium content of shoot dry matter occurred among the genotypes.The winter wheat, winter barley and spring barley genotypes differed significantly (p>0.05) in their efficiency to acquire NaHCO₃-P_i from the rhizosphere soil. The efficiency of the winter wheat genotypes to acquire NaHCO₃-P_i from rhizosphere soil ranked Kraka > Gawain > Foreman > Sleipner = Obelisk > Kosack > Pepital > Arum. Winter wheat genotypes differed in extent of P depletion profiles in the rhizosphere, indicating variation in root hair length. The winter barley and spring barley genotypes also showed significant differences in their P depletion profiles near roots. The efficiency of the winter barley genotypes to acquire soil P in the rhizosphere ranked Hamu > Frost > Marinka > Astrid > Clarine = Angora. The efficiency of spring barley genotypes to acquire NaHCO₃-P_i in the rhizosphere ranked Canut > Etna Riga > Digger > Peel > Semal > Alexis. The rhizosphere pH remained unchanged, suggesting that additional mechanisms such as root hair formation and root exudates play a significant role in causing variation in P acquisition among the genotypes.     

Sowing date and phosphorus utilization by wheat

The uptake and utilization of phosphorus (P) by cereal crops is influenced by the growing period of the crop. In this article the effect of sowing date on the utilization of P by wheat crops grown in southern NSW is reviewed. Crops sown early in the accepted sowing period require smaller inputs of P fertilizer to reach the maximum yield but produce grain with a higher concentration of P than crops sown late in the sowing season. For later sowings a higher rate of applied P is required to achieve the yield potential but this is not associated with a high grain P concentration or a high rate of removal of P from the soil. If grain with a high P concentration is required as seed for subsequent crops, then sowing early, even with little or no applied P fertilizer, is preferable, although crops sown early in the season are likely to remove more P from the soil than the amount applied in fertilizer.     

不同磷源对磷高效利用野生大麦根际土壤磷组分的影响

在土培盆栽条件下,以野生大麦磷高效利用基因型IS-22-30、IS-22-25和低效基因型IS-07-07为材料,研究不施磷(CK)、无机磷(KH₂PO₄,Pi)、有机磷(phytate,Po)及二者混合(KH₂PO₄+phytate,Pi+Po)的方式施磷30 mg·kg^-1时,磷高效基因型野生大麦对磷素吸收利用能力及土壤磷组分特征.结果表明： Pi处理野生大麦干物质量和磷素积累量最大,Pi+Po处理其次,Po处理最小,均显著高于CK处理,且磷高效基因型物质生产和磷素吸收能力显著高于磷低效基因型.土壤有效磷在不同磷源处理间差异显著,Pi处理时含量最高,Pi+Po处理次之,且磷高效基因型野生大麦根际有效磷含量显著高于磷低效基因型.磷高效基因型野生大麦根际有效磷呈现亏缺现象,在Pi和Pi+Po处理时亏缺程度较大.根际与非根际土壤无机磷组分含量为Ca₁₀-P>O-P>Fe-P>Al-P>Ca₂-P>Ca₈-P,且其含量随着Pi的增加而增加.各磷源处理下,磷高效基因型野生大麦根际土壤Ca₂-P、Ca₈-P出现亏缺;Pi处理磷高效基因型野生大麦根际土壤Al-P、Fe-P出现富集.土壤中有机磷各组分含量为中活性有机磷>中稳性有机磷、高稳性有机磷>活性有机磷.野生大麦根际土壤活性有机磷和中活性有机磷呈现富集,其富集量在Pi处理时最大;中稳性有机磷和高稳性有机磷呈现亏缺.各磷源处理下,磷高效基因型野生大麦根际土壤活性有机磷含量显著高于磷低效基因型,中稳性有机磷和高稳性有机磷在基因型间差异不显著.Pi缺乏时,磷高效基因型野生大麦活化吸收Ca₂-P、Ca₈-P、Al-P和活性有机磷的能力较强.     

Genotypic differences in phosphorus efficiency of wheat

In an attempt to evaluate whether breeding and selection for high yielding capacity did change the P requirements of modern wheat cultivars, the response of two wheat cultivars to different levels of P supply was investigated. A traditional cultivar ("Peragis") and a modern cultivar ("Cosir") were cultivated in a C-loess low in available P and high in CaCO₃ in 120 cm high PVC pots. Shoot and root growth at different developmental stages was compared. The grain yield of the modern cultivar Cosir was higher at limiting and non-limiting P supply and, therefore, this cultivar can be considered as more P-efficient than the traditional cultivar. From the results it can be concluded that the main factors contributing to the higher P efficiency of the modern cultivar are (i) efficient use of assimilates for root growth characteristics which enhance P acquisition: smaller root diameter, and longer root hairs, (ii) efficient remobilization of P from vegetative plant organs to the grains, and (iii) lower P requirement for grain yield formation because of lower ear number per plant but higher grain number per ear.     

Effect of phosphorus fertilizer on A values for soils cropped with winter wheat

The effect of successive annual fertilizer P applications (30 kg P ha⁻¹yr⁻¹) on A values (plant availability) for four soils cropped with winter wheat, was investigated over a four-year period under field conditions in the Southern Plains, USA, using P-32 as a tracer. With successive annual fertilizer P applications, winter wheat dry matter yield and A value increased. This increase was linear for wheat yield on each soil (r²=0.77 to 0.97). For A value, the increase was a positive linear function of residual Bray-I P (r²=0.99 to 1.00) and a negative linear function of P-sorption index of the soil (r²=0.94 to 0.98). This was attributed to the fact that continued fertilizer P applications, by decreasing P-sorption index, increased amounts of available P. Consequently, utilization of fertilizer P decreased with successive applications and A value, thus, represents total soil P availability, including native and residual (carry over) fertilizer P. These results confirm earlier suggestions that the A value may be used as a quantitative measurement of environmental and soil factors influencing P availability.