5%调环酸钙泡腾片在水稻生产上的应用试验

通过田间试验,探索植物生长调节剂5%调环酸钙泡腾片在水稻生产上的应用效果,对水稻关键生育期、株高、节间长度、抗倒伏性以及产量等因素进行分析,结果表明,在水稻拔节前10 d喷施5%调环酸钙泡腾片,能够有效降低株高,缩短基部节间长度,减少倒伏发生面积,增加穗数及千粒重,进而达到增产效果,其适宜剂量12～30 g/667 m2。     

沈阳市园林植物标本公园引种驯化应用性探究

以沈阳市园林植物标本公园的引种驯化树种为研究对象,从中抽取观赏价值较高的14种树种进行跟踪调查,其中乔木8种、灌木6种。主要调查其树高、开花期,果熟期、在高温和低温时的生长状况等来讨论其耐寒性和耐旱性,从而讨论引种驯化的可行性。并根据沈阳市的地理环境提出对园林植物进行引种驯化时的几点建议。     

Ethylenediurea (EDU) effects on hybrid larch saplings exposed to ambient or elevated ozone over three growing seasons

Ground-level ozone (O3) pollution is a persis-tent environmental issue that can lead to adverse effects on trees and wood production,thus indicating a need for forestry interventions to mediate O3 effects.We treated hybrid larch (Larix gmelinii var.japonica × L.kaempferi)saplings grown in nutrient-poor soils with 0 or 400 mg L-1 water solutions of the antiozonant ethylenediurea(EDU0,EDU400) and exposed them to ambient O3 (AOZ;08:00-18:00 ≈ 30 nmol mol-1) or elevated O3 (EOZ;08:00-18:00≈ 60 nmol mo1-1) over three growing sea-sons.We found that EDU400 protected saplings against most effects of EOZ,which included extensive visible foliar injury,premature senescence,decreased photosyn-thetic pigment contents and altered balance between pig-ments,suppressed gas exchange and biomass production,and impaired leaf litter decay.While EOZ had limited effects on plant growth (suppressed stem diameter),it decreased the total number of buds per plant,an effect that was not observed in the first growing season.These results indicate that responses to EOZ might have implications to plant competitiveness,in the long term,as a result of decreased potential for vegetative growth.However,when buds were standardized per unit of branches biomass,EOZ significantly increased the number of buds per unit of biomass,suggest-ing a potentially increased investment to bud development,in an effort to enhance growth potential and competitiveness in the next growing season.EDU400 minimized most of these effects of EOZ,significantly enhancing plant health under O3-induced stress.The effect of EDU was attributed mainly to a biochemical mode of action.Therefore,hybrid larch,which is superior to its parents,can be significantly improved by EDU under long-term elevated O3 exposure,providing a perspective for enhancing afforestation practices.     

硅与植物抗逆性研究进展

硅是地壳中含量最丰富的元素之一,同时也是对植物生长发育具有有益作用的元素。硅能使植物细胞壁加厚,提高体内几丁质酶、过氧化物酶和多酚氧化酶活性,增强植物对病虫害如稻瘟病、叶斑病、茎腐病、白叶枯病、小麦白粉病、锈病、麦蝇、棉铃虫、果蔬红粉病等的抵抗能力;硅通过维持植物细胞内部离子平衡、稳定细胞和细胞器的正常结构来防止盐害:硅通过促进植物生长、局部化和钝化重金属离子,缓解重金属对植物的毒害;硅还通过提高植物叶片表面紫外吸收物质含量,形成屏障来阻止紫外线对植物内部结构的伤害:此外硅还能够调节气孔开闭,降低蒸腾作用,从而避免干旱胁迫;硅能在高温胁迫时降低叶片温度,提高植物抗热能力。     

Nutrient status of wheat crop in Ludhiana

Abstract

Samples of wheat plants from 5 selected villages of Ludhiana (Punjab, India) were analysed for P, K, Ca, Mg, Zn, Cu, Fe and Mn. The dominant nutritional deficiencies are found to be those of zinc and copper. The extent of hidden hunger is in the order of Zn > Mg > Cu > K. The low concentrations of Zn and Cu are ascribed to the inherent poor fertility status associated with the lighter texture and low organic matter content. The data suggest that the low concentrations of Mg may be due to high availability of K in some soils. A sharp decline in the higher concentrations of P, K, Mg and Zn with the advancement in the growth stage suggests the importance of stage of growth at the sampling time in evaluating the leaf analysis data.     

Preliminary NPK foliar diagnostic norms for wheat

Abstract

Foliar diagnostic norms for NPK in wheat leaves derived using Beaufils’ Diagnosis and Recommendation Integrated System (DRIS) are presented. These norms were calculated from published and unpublished data of various workers who presented leaf composition with corresponding yields. The preliminary norms appear to be applicable to wheat irrespective of variety and age at which the leaf sample is taken. These norms are able to correctly diagnose the requirements of the crop more often than those based on the critical or sufficiency level approach.     

Sulphur nutrition of clover: Effects of plant age on the composition‐yield relationship

Abstract

Five levels of S (as gypsum) were topdressed on to a pasture containing subterranean clover. Yield responses by the clover fraction of the pasture were measured, together with the total S concentration, the sulphate S concentration and the N:S ratio in young clover plants collected in autumn prior to the fertilizer application, and in plants from the control plots collected in winter and in spring.

As there were irregular changes in analytical values from autumn through winter to spring, a more detailed series of samples was taken in the second year. Therein, values for total S and sulphate S in clover plants from each treatment rose during the winter and fell during the spring, so that the critical concentration of sulphur or sulphate varied during the growing period. However, the critical N:S ratio was relatively stable, and in view of previously demonstrated correlations with response to added S, appears to be the more useful index for both diagnosis and prognosis.     

A comparison between the H2SO4‐H2O2‐Li2SO4‐Se oxidation method and alternative digestion procedures for plant nutrient analysis.

Abstract

Ca, Mg, Na, K and P contents of 3 plant tissues obtained by H₂SO₄‐H₂O₂‐Li₂SO₄‐Se peroxidation digestion were compared with those determined by mixed acid (HNO₃‐H₂S0₄‐HC10₄) and dry ashing procedures. Differences between methods were not consistent between elements or tissue types but the mixed acid digestion generally yielded higher Ca, Mg and P values than did dry ashing and peroxidation. Tissue K contents estimated by both wet digestion techniques were not significantly (P ≤0.05) different. Differences in Na values between digestion methods were highly inconsistent between tissue types and the precision of the Ma data was poor. N contents determined by peroxidation digestion and a conventional Kjeldahl method agreed closely.     

Analysis of cationic elements in liquid samples by x‐ray

Abstract

Plant analyses methods have expanded immensely to document plant mineral element deficiency and toxicity disorders and to note mineral element interactions. Experiments were conducted to determine the feasibility of using cation exchange papers for the extraction of cationic elements from solutions to be analyzed by x‐ray fluorescence. The cationic elements Al, Fe, Mn, Zn, and Cu were effectively extracted from solutions by one exchange resin paper disk if solutions were passed several times through the exchange resin paper. Calcium and Mg were extracted from solutions if two or three separate exchange papers were used, and K was not extracted from solutions with the use of up to five separate exchange papers. The relatively high concentrations of K in solutions and the relatively low exchange capacity of ion exchange resin papers apparently prevented the effective removal of K from solution. The detectability limits on the exchange resin disks by this technique were <2.8 μg Al, 0.5 μg Fe, 0.10 μg Mn, 0.10 μg Zn, and 0.08 μg Cu. Extraction of cationic elements from solutions for x‐ray analysis appeared practical and relatively rapid for Al, Fe, Mn, Zn, and Cu, less practical for Ca and Mg, and impractical for K.     

Rapid perchloric acid digest methods for analysis of major elements in plant tissue

Abstract

The nutrient element composition of tissue from a plant species is not fixed. Composition in the plant varies among different plant parts at the same or different physiological stages of maturity, as soil type changes, from day to day, even hour to hour on the same day due to past and current environmental conditions. These observations seem to undermine the general trend in plant tissue analysis to develop quantitative procedures that are time consuming and, therefore, foster insufficient nutrient status monitoring within and/or between different physiological stages of maturity of like or different plant parts. Therefore, until tissue sampling becomes more definitive, a digest procedure with 90–100% recovery should be more than adequate for major elemental analysis. The HClO₄ digestion procedures described here meet that requirement and take only 15 to 30 min to complete. N recovery was greater than 100% with the H₂O₂‐HClO₄ digestion procedure. However, when HNO₃ was combined with H₂O₂ and HClO₄, N was lost, although even then N volatilization occured only when digestion was extended past clearing.