基于改进基因表达式程序设计的菠菜价格建模及预测

基因表达式程序设计(GEP)是一种基于基因型和表现型的新型进化算法。针对传统GEP遗传算子进行建模及预测时容易受到噪声干扰,导致过早收敛,陷入局部最优等缺点,提出了一种新型GEP算法,增加了"倒串"和"基因提取"算子,该新型算法可以提高基因的有效利用率,具有更高的收敛速度和求解精度,且能更好的避免早熟现象。将该新型GEP算法用在菠菜价格预测上,通过对训练数据进行分析和进化创建数学模型,实现菠菜价格的仿真与预测,通过多组实验证明,该新型基因表达式程序设计算法在菠菜价格预测上具有更快的收敛速度和更高的精度。

Research on Relationship between Recovery Ability after Drought Stress-rewatering and Water Use Efficiency of Winter Wheat Varieties

The study aims at exploring the possibility of using the recovery ability af- ter drought stress-rewatering at vegetative growth stage as the evaluating index in water use efficiency （WUE） of winter wheat varieties. ＇Jing 411 ＇, ＇Jinmai 47＇ and their 34 near isogenic lines （NILs） were used as test materials. Semi-automatic rainproof shelter and the percolating pools were used for simulating drought treat- ment. After suffering severe drought stress, winter wheat crops were rewatered at early jointing stage. The biomass accumulation after rewatering was determined as recovery ability index. In the meanwhile, plant height in the end of vegetative growth stage was measured, and WUE of varieties/lines was also determined. Thereafter, the differences in recovery ability, plant height and the population WUE, together with the correlation between recovery ability and population WUE were analyzed, respectively. The results showed that there were significant differences in recovery ability among some varieties/lines. The recovery ability was affected by both geno- type and environment, and the interaction existed in these two factors. Significant differences existed in plant height and population WUE among the 34 NILs along with their parents. There was a significantly positive correlation between recovery ability and plant height of varieties/lines. Recovery ability and plant height were very significantly and positively correlated with population yield WUE respectively. The re- sults indicated that recovery ability after drought stress-rewatering could be used as an evaluating index of population WUE under drought condition.

Sodium and Potassium Absorption and Distribution in Relation to Growth and Internal Potassium Use Efficiency of K-efficient and -inefficient rice genotypes

A pot experiment with two rice (Oriza sativa L.) genotypes differing in internal potassium use efficiency (IKUE) was conducted under different sodium (Na) and potassium (K) levels. Adding NaCl at a proper level enhanced rice vegetative growth and increased grain yield and IKUE under low potassium. Addition of higher rate of NaCl had a negative effect on the growth of the K-efficient rice genotype, but did not for the K-inefficient genotype. Under low-K stress, higher NaCl decreased IKUE of the K-efficient rice genotype but increased IKUE for the K-inefficient genotype. At tillering stage and under low-K stress, adding NaCl increased K and Na contents and decreased the ratio of K/Na for both genotypes. At harvesting stage under low-K stress, adding NaCl increased K and Na contents and K/Na ratio for the K-efficient genotype but decreased the K/Na ratio for the K-inefficient genotype. The accumulated Na was mostly deposited in the roots and sheaths. At tillering stage, the K and Na contents and the K/Na ratios in different parts for both genotypes decreased in the following sequence: K+ in sheaths > K+ in blades > K+ in roots; Na+ in roots > Na+ in sheaths > Na+ in blades; and K/Na in sheaths 》 K/Na in roots. The K-efficient genotype had a lower K/Na ratio in roots and sheaths than the K-inefficient genotype under low-K stress. At harvesting stage, K and Na contents in grains were not affected, whereas K/Na ratio in the rice straws was increased for the K-efficient genotype but decreased for the K-inefficient genotype by Na addition. However, this was not the case under K sufficient condition.

Genotypic variations in nitrogen use efficiency of rice cultivars at various levels of nitrogen under subtropical environment

Insufficient N supply is an important constraint to productivity of lowland rice. Studies on N nutrition of rice cultivars with different durations representing the north western part of Indo-Gangetic Plains are scanty. A field experiment was conducted during kharif seasons of 2006 and 2007 at PAU, Ludhiana to assess the differences in grain yield and N utilization of three popular rice cultivars at varying N doses. Significant differences among genotypes were observed in grain yield, N uptake, N use efficiency and N utilization efficiency. The cultivar PAU-201 was found to be superior among all the tested genotypes. Total N uptake and grain N uptake was highest in cultivar PAU-201 followed by cultivars PR-115 and PR-113. On an average, the response to applied N for grain yield was observed upto 90 kg N ha1. Grain yield increased significantly up to 90 kg N hal in cultivars PR-115 and PAU-201 and up to 120 kg N ha1 in PR-113. Apparent recovery efficiency （ARE） and Partial factor productivity （PFPN） of N was significantly reduced at higher level of N （150 kg N hal）. It was concluded that N uptake is predominant factor in grain yield formation and cultivars differ in NUE suggesting that it may be possible to develop cultivars that are efficient at low nutrient level or are capable of using N more efficiently when applied as fertilizer.

Suppression of glutamate synthase genes significantly affects carbon and nitrogen metabolism in rice (Oryza sativa L.)

Rice (Oryza sativa) glutamate synthase (GOGAT,EC 1.4.1.14) enzymes have been proposed to have great potential for improving nitrogen use efficiency,but their functions in vivo and their effects on carbon and nitrogen metabolism have not been systematically explored.In this research,we analyzed transcriptional profiles of rice GOGAT genes using a genome-wide microarray database,and investigated the effects of suppression of glutamate synthase genes on carbon and nitrogen metabolism using GOGAT co-suppressed rice plants.Transcriptional profiles showed that rice GOGAT genes were expressed differently in various tissues and organs,which suggested that they have different roles in vivo.Compared with the wild-type,tiller number,total shoot dry weight,and yield of GOGAT co-suppressed plants were significantly decreased.Physiological and biochemical studies showed that the contents of nitrate,several kinds of free amino acids,chlorophyll,sugars,sugar phosphates,and pyridine nucleotides were significantly decreased in leaves of GOGAT co-suppressed plants,but the contents of free ammonium,2-oxoglutarate,and isocitrate in leaves were increased.We conclude that GOGATs play essential roles in carbon and nitrogen metabolism,and that they are indispensable for efficient nitrogen assimilation in rice.