植物生理与分子生物学学报最新文献

Self-incompatibility (SI) is an important intraspecific reproductive barrier in flowering plants. To identify the S-alleles of Chinese pear species (Pyrus pyrifolia, P. bretschneideri, P. ussuriensis and P. sinkiangenis etc.), S-RNase-specific PCR amplification, sequence analyses and field pollination tests were performed using two cultivars 'Jingxiang' and 'Esu' of P. bretschneideri as materials. Two new S-RNase genes were identified from the two cultivars. They were 1,122 bp and 1,058 bp in length, and designated as S37-RNase (GenBank accession no. DQ839238) and S38-RNase (GenBank accession no. DQ839239). By comparison of their deduced amino acid sequences with those of S1-to S36-alleles of Oriental pear, it can be seen that both the two new S-alleles had their conserved regions C1 and C2, but their hypervariable regions (HV) were quite different from those of the others. S37 showed a higher similarity (96%) to S38 in the amino acid sequences deduced from them, whereas both of them displayed the highest similarity (98%) to S15 and the lowest (63%) to S32. The two S-alleles had introns of 786 bp and 723 bp, respectively, similar in size to that of S15 (777 bp). Finally, the S-genotypes of 'Jinxiang' and 'Esu' were unambiguously determined as S34S37 and S15S38, respectively.

ISSR (inter-simple sequence repeat) and RAPD (random-amplified polymorphic DNA) markers were used to detect genetic diversity of 4 different ecotypes of reed (Phragmites communis Trin.) growing in Hexi Corridor, Gansu province. Nine effective primers were screened from 30 ISSR arbitrary primers, and a total of 99 DNA bands were amplified, among which 51 (51.5%) were polymorphic. Thirteen effective primers were screened from 45 RAPD 10-oligonucleotide arbitrary primers, and a total of 195 DNA bands were amplified, among which 87 (44.6%) were polymorphic. Genetic identity based on ISSR and RAPD data showed a positive correlation (r=0.845, P<0.05). Based on unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis on DNA bands amplified, together with the correlation analysis between genetic distance and soil water contents and soluble salt contents as well, the present results suggest that the genetic diversity occurs among the four ecotypes of reed in adaptation to long term natural drought and salinity, showing an obvious evolutional tendency from swamp reed via salt meadow reed to dune reed.

The seedlings of the F4 hybrid strain 'JB185' selected for salt tolerance generation by generation, their parents Glycine max cv. Jackson and Glycine soja population 'BB52' were treated with different NaCl concentrations and iso-osmotic (-0.53 MPa) PEG-6000, NaCl, Na+ (without Cl-) and Cl- (without Na+) solutions for 6 d. The results showed that: (1) The relative electrolyte leakage and malondialdehyde (MDA) content in leaves of the above three soybean seedlings showed an increase trend when the NaCl concentration was elevated, but chlorophyll contents decreased except the significant increase in 'BB52' and 'JB185' under NaCl 50 mmol/L stress. The change in 'JB185' was between its parents. (2) Under different iso-osmotic stresses, the relative electrolyte leakage and MDA contents in leaves of three soybean seedlings also increased mostly, the changes in 'BB52' and 'JB185' under Na+ (without Cl-) stress were more than those under Cl- (without Na+) stress. The free and bound Put, Spd and Spm contents in leaves all increased when compared with the control, the ratios of free (Spd+Spm)/Put and total bound polyamines in 'BB52' and 'JB185' seedlings under Na+ (without Cl-) treatment were the lowest one among three iso-osmotic salt stresses. The results indicate that the F4 hybrid strain 'JB185' is more sensitive to Na+ than Cl- as its wild parent 'BB52' population.

Y-shaped adaptor dependent extension (YADE) method is a useful tool to amplify the flanking sequence of a known DNA sequence, but its efficiency is frequently limited by the restriction sites around the known sequence. In this paper, we demonstrated that using multiple templates derived from several restrictions and ligations could dramatically increase the efficiency of YADE method and render it suitable for sequential amplification of flanking sequences. With templates originating from 7 digestions, a 2,228-bp 5'-upstream sequence of a cotton small GTPase gene was obtained by two rounds of sequential YADE amplifications. The results demonstrated that the YADE method with multiple templates may be a useful tool for sequential PCR walking in complex genomes.

In this study, the pitted peel and non-pitted peel of 'Fengjie' navel orange fruits were used as experimental materials to construct and screen the peel pitting related genes by suppression subtractive hybridization (SSH). The results showed that suppression subtractive hybridization was very effective. A cDNA library of differentially expressed genes was constructed. The library included about 200 clones with an average insert size of around 300 bp. Part of the positive clones were picked up randomly and sequenced. Six of the 50 clones had no homologous sequences being found and three had unknown functions in GenBank. According to the analysis of the homology, four homologous (Ca2+ binding protein, cysteine proteinase, NAC-domain protein and expansin) genes were chosen to examine their expressions through semi-quantitative RT-PCR analysis in pitted and non-pitted navel orange fruits. The expression of four genes were all higher in pitted peel than that in non-pitted peel. It suggests that these genes in the SSH cDNA library may be involved with peel pitting and can be subject of future investigation to explore the molecular biological mechanism of the pitting of citrus fruit.

Thioredoxin h is closely related to germination of cereal seeds. The mechanism of transgenic wheat seeds with antisense trxs gene, which is responsible for low germination rate was studied through analyzing the changes in proteins of wheat seeds during germination. The antisense trxs could weaken the metabolism of wheat seeds by decreasing the quantity of proteins involved in metabolism, while chloroform-methanol (CM) protein fraction consisted mostly of some low molecular weight proteins (<20 kD). Compared with wild-type wheat seeds, the folding of glutenin in transgenic wheat ones was affected during the wheat maturating. Big glutenin macropolymers could be formed more easily in transgenic wheat seeds than in wild-type wheat ones. Therefore, the degradation speed of glutenin in transgenic wheat seeds was slower than that in wild-type wheat ones during seed germination. In addition, the degradation of some proteins in transgenic wheat embryos was also delayed during germination.

L-arginine is an important and unique amino acid in plants. It serves not only as an important nitrogen reserve and recycling, but also as a precursor of the biosynthesis of polyamines, nitric oxide and so on. Polyamines and nitric oxide are important messengers involved in almost all physiological and biochemical processes, growth & development, and adaptation of plants to stress. Arginine decarboxylase, arginase and nitric oxide synthase are the key enzymes in L-arginine catabolism, in which polyamines are formed through ADC or arginase-ODC pathway while nitric oxide is formed through the NOS pathway. The relative activity of these three enzymes can control the direction of arginine metabolism. Arginine content keeps higher level in roots during overwinter period. The arginine metabolism plays important role in perception and adaptation of plant to environmental disturbances.

Immature zygotic embryos of Quercus variabilis Bl. were excised and cultured on MS basal medium containing 0.25 mg/L 2,4-dichlorophenoxyacetic acid and 0.5 mg/L 6-benzyl aminopurine. Callus was initiated from these embryos within 6 weeks. Two types of embryogenic calluses were formed: one was the white mucilaginous callus and the other was light yellow to translucent, glossy, mucilaginous. Histological examination showed that the non-embryogenic cells derived from zygotic embryos were large in size, with small nuclei, thin cytoplasm, and the embryogenic cells were small in size, with large nuclei, thick cytoplasm and denser arrangement. Somatic embryos were induced from embryogenic masses (EMS) cultured on a medium not containing plant growth regulators (PGRs). The histological origin of somatic embryos was single epidermal or subepidermal cells. Somatic embryos displayed a standard development pattern, from globular ones to heart-like and torpedo-shaped ones and finally to embryo with two cotyledons, which was similar to the development of zygotic embryo in vivo. Secondary proembryos were formed on the axis and cotyledon of existing embryos and originated from single, densely stained cells of the epidermis at all stages.

Potassium pyroantimonate precipitation method was used for investigating calcium distribution and cell ultrastructure change during development of pistils of litchi male and female flower. The results showed that at the megasporocyte stage of female flowers, calcium precipitates was located mainly at cell wall and intercellular space of inner integument near the micropyle and style cells, and to a lesser extent in vacuoles. Vascular tissues also contained much calcium precipitates. In inner integument cells near the micropyle of male flowers, the vacuole contained most of the calcium precipitates. Calcium precipitates in style cell and vascular tissues of male flowers was sparse and seldom seen. After meiosis of megasporocyte, pistils of female flowers continued to grow and those of male flowers aborted. In female flowers, calcium precipitates concentration became lower and calcium precipitates was probably transported to the places for future pollen bourgeoning and fertilization. Cell wall calcium precipitates concentration increased in the inner integument cells near the micropyle. Calcium precipitates concentration increased from topper style cells to lower ones. In male flowers, inner integument cells near the micropyle underwent the programmed cell death (PCD): flow of calcium from vacuoles into nucleus might had triggered the PCD process. A continuous channel was formed between perinuclear space and cytoplasm membrane lumen, and calcium flowed freely between nuclear membrane and plasma membrane. At certain time and locations, calcium precipitates was newly appeared at some organelles like endoplasimic reticulum, mitochondria and peroxisomes. This calcium redistribution in cells might trigger and regulate the process of PCD. In male flowers, style cells containing no calcium precipitation soon began to degenerate.

We studied the growth state of tomato seedlings and the adaptive changes in activity of tonoplast H(+)-ATPase on different days (5 d, 7 d, 9 d, 11 d, 13 d) sampling from the roots of tomato seedlings under phosphorus starvation. The results indicated that the average height of the seedlings decreased under phosphorus starvation, while the main roots of the seedlings were significantly longer than those of the control. The phosphorus uptake rates of tomato seedlings under phosphorus starvation significantly increased and were much higher than those of controls and reached maximum values under the starvation for 7 days. The tonoplast H(+)-ATPase activity in the roots of tomato seedlings increased under phosphorus starvation and reached maximum values under the starvation for 7 days, while the activity of the control changed little. Kinetic analysis of tonoplast H(+)-ATPase showed that phosphorus starvation significantly lowered the K(m) value, but had no significant effect on the V(max) value of the enzyme. The results showed that phosphorus starvation increased the affinity of the enzyme to its substrate. In addition, phosphorus starvation did not alter the optimum pH (7.5) of the ATPase activity.