Effects of salinity on activities of H^+-ATPase, H^+-PPase and membrane lipid composition in plasma membrane and tonoplast vesicles isolated from soybean(Glycine max L.) seedlings

The effects of NaCl stress on the H +-ATPase, H +-PPase activity and lipid composition of plasma membrane(PM) and tonoplast(TP) vesicles isolated from roots and leaves of two soybean cultivars(Glycine max L.) differing in salt tolerance(Wenfeng7, salt-tolerant; Union, salt-sensitive) were investigated. When Wenfeng7 was treated with 0.3%(W/V) NaCl for 3 d, the H +-ATPase activities in PM and TP from roots and leaves exhibited a reduction and an enhancement, respectively. The H +-PPase activity in TP from roots also increased. Similar effects were not observed in roots of Union. In addition, the increases of phospholipid content and ratios of phospholipid to galactolipid in PM and TP from roots and leaves of Wenfeng7 may also change membrane permeability and hence affect salt tolerance.

A Preliminary Study on Dynamics and Models of N,P,K Absorption for High-Yield Cotton

The field experiments were carried out to investigate the dynamics and models of N, P and K absorption for the cotton plants with a lint of 3 000 kg ha-1 in Xinjiang. The main results were as follows: The contents of N, P2O5, K2O in cotton leaves, stems, squares and bolls decreased obviously with the time over the whole growth duration and the falling extent was greater in high-yield cotton than in CK. Contents of N in leaves, squares and bolls, in particular in the leaves of fruit-bearing shoot was higher in high-yield cotton than in CK. Contents of P2O5 in squares and bolls and that of K2O in stems were higher in high-yield cotton than in CK during the whole growing period. The accumulations of N, P2O5 and K2O in the cotton plants could be described with a logistic curve equation. There was the fastest nutrient uptake at about 90 d for N, 92 d for P2O5 and 85 d for K2O after emergence, respectively. Total nutrient accumulation of N, P2O5 and K2O was 385.8, 244. 7 and 340.3 kg ha-1, respectively. Approximately 12. 5 kg N, 8. 0 kg P2O5 and 11.1 kg K2O were needed for producing 100 kg lint with the leaves and stems under the super high yield condition of 3 000 kg ha-1 in Xinjiang.

Differential Response of Grain Quality to Cold Water Irrigation in Cold Tolerant and Sensitive Lines of Rice

Three rice varieties and several F3 lines with high and low cold tolerance, selected from F3 segregation lines of two crossesMilyang 23/Tong 88-7 and Milyang 23/TR22183 were used to analyze the effects of cold tolerance on the response of grainquality to cold water irrigation. The result showed that cold water irrigation led to the decrease of rice grain size. Thelength, length-width ratio and weight of brown rice grain were more sensitively affected by cold water irrigation than thewidth and thickness. The shape of brown rice grain was not significantly affected by the selection for cold tolerance at theseedling stage (CTS). The gel consistency, amylose content, peak viscosity, cool viscosity, breakdown viscosity andconsistency viscosity were decreased, while alkali digestibility value and protein content were increased by cold waterirrigation. Under normal irrigation condition the physicochemical properties of milled rice and viscogram components ofmilled rice flour were not significantly different between lines with high and low cold tolerance. Under cold water irrigationthe amylose content, peak viscosity, hot viscosity, final viscosity of rice lines with high CTS or high cold tolerance at thebooting stage (CTB) were higher, while the protein content, setback viscosity, breakdown ratio and setback ratio werelower, than those of rice lines with low cold tolerance. This implied that the cold water response of rice grain quality wasless sensitive in the lines with high cold tolerance than in the lines with low cold tolerance, and the varietal improvementfor cold tolerance would be important for grain quality improvement at the same time.

Detection of RAPD Markers Linked to Gene lx_1 in Soybeans

Near-isogenic lines of soybean lipoxygenase, which contain genes Lox, lx1, lx2, lx3, lx1.3, lx2.3,respectively, were used for polymorphic analysis by RAPD technique.520 10-mer-oligonucleotideprimers were screened, and thirteen primers showed polymorphism among near-isogenic lines.There were six primers showed special polymorphic bands among lines lx1 and lx1.3. Especially,primer S352 presented the stable results in which a 900 bp band was found in the lines lx1 andlx1.3, and primer S352900 was detected with F2 generation of cross 96P11×Century-1, indicatedprimer S352900 could be identified as a RAPD marker linked to gene lx1 in soybeans, the distanceof linkage was 7.6 cM.

Characterization of RAPD Markers,and the RFLP Marker Linked to Powdery Mildew Resistance Gene Derived from Different Accessions of H.villosa

The analysis was carried out on performance of the resistance gene from Haynaldia villosa accession of the former Soviet Union to different isolates of Bluemerie graminis. Polymorphisms were revealed between 6D/6V substitution line Pm930640 and its pedigree parents using five RAPD markers of OPAN031700, OPAI01700, OPAL03750, OPAD07480 and OPAG15580 screened out from 120 random 10-mers primers. Three RAPD markers of OPAN03, OPAI01 and OPAL03 were linked with the resistance gene by analysis of F2 population of Chancellor×Pm930640. Analysis of 29 wheat lines including part of lines conferring the known genes from Pm1 to Pm20 respectively, lines conferring resistance gene from two H. villosa accessions and the related wheat parents, were analyzed and the results showed that these markers not only linked to the gene resistant to powdery mildew from H. villosa, but also detected different genetic backgrounds. OPAL03750 can be used as the marker to distinguish the different resistant lines from two H. villosa accessions because it was only observed in the materials from H. villosa of the former Soviet Union. RFLP analysis also showed the polymorphisms between two H. villosa accessions and their derived resistant lines.

Effect of Different Norms of Under-Mulch-Drip Irrigation on Diurnal Changes of Photosynthesis and Chlorophyll Fluorescence Parameter in High Yield Cotton of Xinjiang

Under-mulch-drip irrigation is an advanced irrigation technique, which combines plastic-film-covered cultivation with drip irrigation. The influence of different norms of under-mulch-drip irrigation on diurnal changes of photosynthetic rates and chlorophyll fluorescence parameters of cotton was studied, in order to understand the physiological mechanisms of water-saving and high-yielding farming in Xinjiang. Results indicated that limited drip irrigation, which supplies 2/3 of 375 m3 ha-1, the widely-used irrigation norm in cotton cultivation in Xinjiang, caused a water deficit in cotton field. Compared with the proper drip irrigation, the leaf photosynthetic rate under limited drip irrigation decreased during 9:00 to 11:00 a. m. , and was significantly suppressed at midday, and then recovered afterwards. Using the chlorophyll fluorescence method, the absorption, transfer and transformation features of solar radiation by cotton leaf were investigated. Under limited drip irrigation, the variable fluorescence (Fv) and primary light transfer efficiency of PSII (Fv/Fm) in cotton leaves were reduced because of the high light intensities and high temperatures at noon, and the decrease in XinluzaoS was greater than that in Xinluzao6. Therefore, it could be concluded that Xinluzao6 has a higher drought-tolerance, and the Fv/Fm ratio could be used as a drought-resistance index for cotton.

Individual Cotton Boll Weight as Influenced by Different Production Eco-Regions and Meteorological Factors

In order to explore systematically the physiological mechanism of high yield cotton ( Gossypium hirsutum L.) in Xinjiang, and further improve yield, the yield components were compared between three ecological regions. Boll number per plant was lower in South and North Xinjiang, but the harvested plant population were nearly 1.5 times higher than that in Nangong, so total boll numbers per unit area were greater in South and North Xinjiang. Weight per boll in south and north of Xinjiang was 5.896.50 g and 5.43 6.12 g respectively, 24 to 51% heavier than that in Nangong. The diurnal temperature difference between day and night was relatively greater in Xinjiang than in Nangong, benefitting the accumulation of photosynthetic product in bolls. The temperature difference and total hours of sunshine in boll period are the main reasons for cottons higher boll weight and yield in Xinjiang than in Nangong.

The Relationship Between Temperature & Sunshine and Spring-Sown Wheat Quality

In order to study the relationship between temperature & sunshine and spring-sown wheat qua lity, a spring-sown experiment with 3 wheat varieties was conducted in Rikaze, Lasa, Linzhi, Beijing and Shenyang from 1998 to 2001. The results indicated that significant difference on some quality characteristics of experimental wheat varieties were observed from different locations and different years. The results also showed: protein content was positively correlated with wet gluten content, falling number, the average day temperature and sunshine hours from heading to maturation; and negatively correlated with the growing days and the average diurnal temperature difference from sowing to maturation; wet gluten content was positively correlated with the average day temperature and sunshine hours during the same period. Sedimentation value and falling number were positively correlated with the average sunshine hours from sowing to maturation. The basic way of wheat production in Tibet was as follows: mainly developing medium gluten wheat varieties, suitably planting weak gluten wheat varieties, introducing some inland excellent varieties.

Analysis of rice blast resistance genes by QTL mapping

Resistance to rice blast pathogen mostly shows a quantitative trait controlled by several minor genes. Its complexity and the mutable characteristic of rice blast iso-lates both hinder the development of the blast resistance re-search. The article here tried to explore the resistance gene distribution on rice chromosomes and the way of function. Totally 124 QTLs have been identified against 20 isolates using Cartographer software with a ZYQ8/JX17 DH popula-tion, which separately are at 100 loci of 72 marker intervals on 12 rice chromosomes. Of them, 16 QTLs were determined by the isolate HB-97-36-1. 82 QTLs (66.13%) are from the resistant parent alleles, ZYQ8, while 42 QTLs (33.87%) are from the susceptible parent alleles, JX17. In comparison of their positions on chromosome, most QTLs are clustered together and distributed nearby the major genes especially the regions on chromosomes 1, 2, 8, 10 and 12. Each QTL could account for the resistance variation between 3.52%—68.64%. And, a positional QTL might display the resistance to several different isolates with different contributions.

Identification of retrotransposon families and analysis of their transcriptional activation in wheat

Variations in the reverse transcriptase (RT) domain were analyzed to clarify retrotransposon family structure and their evolution in wheat genome. RT-PCR was conducted by using primers based on the conserved RT pep- tide motifs of plant retrotransposons to amplify the RT do- main of retrotransposons in the seedlings of wheat line Pm97034 treated with powdery mildew fungus. High level of heterogeneity was detected in 51 (RT1-51) clones randomly selected and the identity of nucleotide sequence among them ranged from 75.4% to 97.9%. These sequences, in combina- tion with previously identified seven representatives from wheat retrotransposon families (families 1―7), were used to construct a composite phylogenetic tree. Three new families, designated family 8 to family 10, were identified. Famliy 8 formed before divergence of the Pooideae subfamily and was regarged as an ancient retrotransposon family. Some mem- bers of family 4 and family 7 had transcriptional activativity, and were present with multiple copies in wheat and its re- lated species.

Identification and Characterization of Reverse Transcriptase Domain of Transcriptionally Active Retrotransposons in Wheat Genomes

To clarify activation characterization of wheat (Triticum aestivum L.) retrotransposons, transcriptionally active Ty1-copia retrotransposons were found in wheat by using RT-PCR to amplify the RT domain. Sequence analysis of random RT-PCR clones reveals that Ty1-copia retrotransposons are highly heterogeneous and can be divided into at least four groups, which are tentatively named TaRT-1 to TaRT-4.Dot blot hybridization indicates that TaRT- 1 exists in the wheat genome as multiple copies (at 30 000 copies/a hexaploid genome (ABD)). Northern blot hybridization showed that TaRT-1 is only expressed at a low level under normal conditions in seedlings, but at a high level when induced by powdery mildew fungus, jasmonic acid (JA) and salicylic acid (SA). These results suggest that the TaRT-1 expression is highly sensitive to biotic and abiotic stresses.