EFFECT OF NITROGEN AND PHOSPHORUS ON THE GROWTH OF A RED TIDE DINOFLAGELLATE SCRIPPSIELLA TROCHOIDEA (STEIN) LOEBLICH III

Scrippsiella trochoidea (Stein) Loeblich III was grown in a nitrogen or phosphorus limited batch culture system in laboratory. Growth rates and cellular Chl a were measured as functions of nitrate and phosphate concentrations. Growth rates were hyperbolic with both nitrate and phosphate concentration and fit the Monod equation. The minimum cell quota of nitrogen and phosphorus and then the optimum N:P ratio of S. trochoidea were estimated in this study. Measurement of phosphate concentration in Jiaozhou Bay suggest that phosphorus is the limiting factor of S. trochoidea growth.

Cottonseed yield and its quality as affected by mineral fertilizers and plant growth retardants

The increase in the population in Egypt makes it imperative to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the Egyptian people. Cotton is the principal crop of Egyptian agriculture, it is grown mainly for its fiber, but cottonseed products are also of economic importance. Cottonseed is presently the main source of edible oil and meal for livestock in Egypt. Economic conditions in modern agriculture demand high crop yields in order to be profitable and consequently meet the high demand for food that comes with population growth. Oil crop production can be improved by development of new high yielding varieties, and the application of appropriate agronomic practices. There is limited information about the most suitable management practice for application of N, P, K, Zn, Ca and PGRs in order to optimize the quantity and quality of oil and protein of cottonseed. In maximizing the quantity and quality of a crop’s nutritional value in terms of fatty acids and protein, field experiments were conducted to investigate the effect of nitrogen, phosphorus, potassium, foliar application of zinc and calcium, the use of plant growth retardants (Pix, Cycocel or Alar), on cottonseed, protein, oil yields, and oil properties of Egyptian cotton. From the findings of this study, it seems rational to recommend that application of N, P, K, foliar application of Zn and Ca, the use of PGRs (Pix, Cycocel or Alar), could bring about better impact on cottonseed yield, seed protein content, oil and protein yields, oil refractive index, unsaponifiable matter, and unsaturated fatty acids in comparison with the ordinary cultural practices adopted by Egyptian cotton producers.

Direct and residual effects of plant nutrition’s and plant growth retardants, on cottonseed

Seed quality is one of the most important factors for stand establishment in cotton (Gossypium Sp.), and the use of good-quality seeds is therefore essential to obtain an optimum plant population. Conditions prevailing during seed formation can affect the quality of seed produced, and hence crop establishment in the next growing season. These conditions can affect the germination of the seeds and the ability of the seedlings to emerge from soil. Field experiments were conducted to investigate the effect of nitrogen (N), phosphorus (P), potassium (K), foliar application of zinc (Zn) and calcium (Ca), and the use of plant growth retardants (PGR) [e.g., 1, 1-dimethyl piperidinium chloride (MC);2-chloroethyl trimethyl ammonium chloride (CC);or succinic acid 2, 2-dimethyl hydrazide (SADH)], during square initiation and boll setting stage, on growth, seed yield, seed viability, and seedling vigor of Egyptian cotton (G. barbadense). Dry matter yield, total chlorophyll concentration, K, Zn and P-uptake plant-1, were increased with the addition of K, foliar application of Zn, and different concentrations of P (576-1728 g·ha-1 of P). Seed yield plant-1 and plot-1, seed weight, seed viability, seedling vigor, and cool germination test performance increased as a result of the addition of the high N-rate (142.8 kg·ha-1 N), the high P-rate (74 kg·ha-1 P2O5), K (47 kg·ha-1 K), and from application of Zn, and Ca and the PGR. From the findings of the present study, band application of such treatments showed improved cotton-seed yield and affected the quality of seed produced, and hence crop establishment in the next growing season.

Influence of the Macronutrients N, P and K on the Agarophyte <i>Alsidium triquetrum</i>(S. G. Gmelin) Trevisan, during Experimental Culture

The knowledge of the nutritional requirements and their relation to the physiology of marine algae growth is key to incorporate new species into aquaculture, whose dynamics tend to be largely unknown. The use of Alsidium triquetrum in the pharmacological industry depends on its availability in the natural environment, occasionally scarce. As macroalgae cultivation gains momentum worldwide, it is important to know how the effects of nutrients are modulated in the thallus during cultivation. The linking of the relative growth rates (RGR) of A. triquetrum and their relation with the macronutrients N (nitrogen), P (phosphorus) and K (potassium) at the tissue level under culture conditions constitutes the main contribution of this article. P levels tend to decrease as the plant completes its development. Both the concentration of N and P are higher in the stipe for the month of July, N (25.31 ± 0.26) vs P (0.846 ± 0.02) period when the highest vegetative development is reached. The N and P modulate the patterns of the species’ development over the annual cycle, unlike K, which is not considered a limiting factor. When the temperature and lighting are not favorable for growth, the plant simply accumulates these compounds. As environmental conditions change, these stored compounds are actively used in their growth. The specimens with an initial weight of 50 g present the best accumulated biomass (RGR) throughout the annual cycle.

水肥供应对番茄生长及产量形成的影响

以"金鹏1号"番茄为试验材料,通过盆栽试验,对处于不同灌水量和氮、磷、钾肥用量条件下的番茄生长及产量进行分析。在此试验条件下,各因素对叶片数的因子贡献率的主次关系为:施氮量=施磷量>灌水量>施钾量;对叶果比的影响表现为:灌水量>施氮量>施磷量>施钾量;坐果率表现为:灌水量>施氮量>施磷量>施钾量;60%~83.78%的灌水量有利于降低叶果比进而促进产量的增加;氮肥、磷肥用量达到0.96 g·kg^(-1)、P_2O_50.528 g·kg^(-1)土时会导致叶片数和叶果比增加,坐果率和产量下降;随着灌水量、施氮量、施钾量的增加番茄产量呈先增后减的趋势,在灌水量为83.78%W,施氮量为0.77N g·kg^(-1)土,施磷量为P_2O_50.421 g·kg^(-1)土,施钾量为K2O 0.670g·kg^(-1)土时产量达到最大值为467.5 g·株^(-1)。

氮、磷、钾肥料用量对泉薯9号生长和产量的影响

研究了氮、磷、钾肥不同用量（N：0、60、120、180kg／hm^2；P2O5：0、45、90、135kg／hm^2；K2O：0、90、180、270kg／hm^2）对泉薯9号在红壤旱地上生长及产量的影响。结果表明，氮肥对甘薯营养生长和产量有良好的促进作用，甘薯叶片叶绿素含量（SPAD值）、主茎长、一次分枝数、一次分枝长、全株叶片数和甘薯产量均随施氮量的增加而增加。磷肥对甘薯营养生长影响较小，不同用量之间的甘薯营养生长指标差异不显著，但磷肥对甘薯产量有明显的影响，随着磷肥用量的增加，产量呈抛物线形态。施钾在0—180kg／hm^2之间对甘薯营养生长的影响较小，当用量达270kg／hm^2时，则对甘薯营养生长有一定的抑制作用。钾肥有利于提高产量，随着钾肥用量的增加，甘薯产量呈直线增长趋势。

矮生沿阶草适宜液肥配方的初步研究

为加速矮生沿阶草的繁殖和推广,通过N、P、K3因素不同配比施肥,研究不同NPK的配合施用对矮生沿阶草生长的影响。综合叶片伸长速率、展开速率、叶绿素含量、新根发生数量、根系活力等测定结果认为,NPK适当配比才能促进其正常生长,处理N2P2K1、N2P2K2能较好地调节矮生沿阶草地上、地下生物量分配,促进植株快速生长。适宜矮生沿阶草生长的专用肥配方为N、P2O5、K2O按照7:3(:8～8.5)配比。

不同浓度氮、磷、钾对蝴蝶兰幼苗生长的影响

采用氮、磷、钾3因素4水平全因子试验设计,研究了不同浓度营养液处理对蝴蝶兰幼苗生长的影响。结果表明:氮浓度250mg/L、磷浓度15mg/L、钾浓度150mg/L对蝴蝶兰幼苗生长、叶面积增长较适合。高磷(60mg/L)降低幼苗叶长、叶宽及叶面积生长速率;高氮(350mg/L)促使叶细长薄弱,对提高叶面积增长率作用不大;高钾(250mg/L)有助于幼苗叶面积增长率提高和干物质的积累;幼苗叶面积的增长率与叶宽的增长率呈显著正相关;施肥有助于叶宽增长从而促进蝴蝶兰幼苗的叶面积增长。

氮肥和氮磷钾配比对蓖麻生育特性、干物质积累和产量的影响

在粘壤土上开展试验,研究了施氮量和氮磷钾配比对蓖麻品种淄蓖7号生长特性、干物质积累和产量的影响。结果表明:施氮量、氮磷钾配比以及两者互作对蓖麻的生长特性、干物质积累和产量均产生了显著或极显著的影响;随着施氮量从225.0 kg/hm^2到375.0 kg/hm^2、氮磷钾配比从1∶0∶0提高到1∶0.9∶1.5,蓖麻的株高、叶干重、茎干重、叶面积指数、籽粒产量均显著增加;籽粒产量的增加主要来源于每株穗数的增加和百粒重的提高;施氮量375 kg/hm^2、氮磷钾配比1∶0.9∶1.5处理的籽粒产量最高,达2163.6 kg/hm^2。