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2005  Vol. 23  No. 2

Abstract:
During the development of the anthers,potassium antimonite was used to locate Ca2+ in fertile and sterile anthers of purple cytoplasmic male sterile rice(Oryza sativa L.ssp.indica).In the fertile anthers,there was abundant Ca2+ precipitates on the surface of early microspore,but not in cytoplasm;In the tapetum,there were little calcium precipitates in cytoplasm in the early stage,in the later stage,tapetum cells suffered programmed cell death and a great quantity of calcium was precipitated.In the sterile anthers,the pollen mother cell aborted at the meiosis stage and abundant calcium was precipitated in vacuolated cytoplasm.There were abundant Ca2+ preci-(pitates)between tapetum and pollen mother cells or between tapetum and microspores,but not in the tapetum cells.The results indicate that abnormalities in the distribution of calcium between tapetum and pollen mother cells,which is the same between tapetum and microspore,are correlate with cytoplasmic male sterility.
Abstract:
Genomic exchange and rearrangement of the amphidiploid species Cucumis hytivus and its effect on fertility of male gametophyte were cytologically studied through making slides.Cytolo-(gical)evidences for genomic exchange and rearrangement were found,such as"8"and"cross"configu-(rations)at prophase,chain and ring multivalents at metaphase Ⅰ,as well as various abnormal chro-(mosome)structure including chromosome bridges,lagging,genomic separation,micronuclei etc,which probably resulted in unequivalent distribution of genetic germplasm.Such an extensive geno-(mic)exchange and rearrangement led to 93% polyads and some abnormal tetrads.Abnormal micro-(spores)in polyads and microspores with unbalance germplasm could not develop into normal male gametophytes,which is responsible for the low fertility of male gametophyte in Cucumis hytivus.
Abstract:
Honglian-type CMS(CMS-HL)is one of the most extensively used cytoplasms in hybrid rice of China.In order to map both major and minor QTL controlling fertility restoration for CMS-HL,a Honglian-type male sterility line(YTA)was test-crossed to the RILs derived from a cross between Lemont and Teqing.Composite interval mapping was conducted based on the data of spikelet fertility and pollen fertility in the test-cross population of YTA/RILs.Significant difference between the two parents Lemont and Teqing in fertility restoration was observed and Teqing showed a much stronger fertility restoration than Lemont.Totally,four QTL for spikelet fertility and pollen fertility were mapped to chromosomes 1,2 and 10 of all the twelve rice chromosomes,each explaining 5%-24% of the trait variation.Among these QTL,three QTL with their positive alleles were from the parent Teqing.QTL qRF-10-1,mapped onto the interval RM258-C16 of chromosome 10,produced the largest effects on both the two traits,accounting for 24% of the spikelet fertility variation and 17% of the pollen fertility variation.Comparatively,the other three QTL produced much small effects on the traits,each explaining less than 10% of the trait variation.These results indicated that the fertility restoration of the RILs was mainly controlled by the major QTL qRF-10-1 and was also modified by the other three minor QTL.This suggestion was further confirmed by the continuous binary frequency distribution of spikelet fertility in the test-cross population of YTA/RILs.QTL qRF-10-1 with the most closely linked SSR marker of RM258 could be used as a target to be manipulated in breeding restoration lines for HL-CMS.
Abstract:
Cold stress is one of the major restraints for stable stand establishment at the early seedling stage of rice(Oryza sativa L.)for much of the production area.A recombinant inbred line population derived from a japonica/indica cross were assessed for cold tolerance at early seedling stage by the paper-roll tests at 10°C.Main-effect QTL for the trait were mapped via composite interval mapping using a linkage map with 198 marker loci.Four putative QTL for the trait were identified,which were mapped to chromosomes 1,3,7 and 11,respectively.Among these QTL,qSCT-11 showed a large additive effect on the trait,explaining 26%-30% of the phenotypic variation in the treatment of 13 d at 10℃ with a LOD of 16-19.This QTL was closely linked to SSR marker RM202 and its positive allele came from the parent Lemont.This allele would be useful for the improvement of rice cold tolerance via marker-assisted selection.
Abstract:
A recombinant inbred line population of rice(Oryza sativa L.)was directly seeded in plastic pots in a randomized complete block with two treatments,control(normal fertilizer level)and no fertilizer.Seedling height was measured at stages Ⅰ(25 days after seeding)and Ⅱ(50 days after seeding),respectively.Composite interval mapping was carried out using a high density linkage map based on the same population,leading to the identification of 8 main-effect QTL for seedling height,each explaining 4%-12% of the phenotypic variation.Comparing the QTL identified under two fertilizer levels resulted in a finding that most of the QTL showed effects on the trait only under one fertilizer level,indicating presence of significant QTL by fertilizer level interactions.Only one QTL(qSH-3-2)was found to produce consistent additive effect on the trait under two fertilizer levels.This QTL was located to the interval RM156-RM16 of chromosome 3 and its positive allele contributed by the parent Lemont.In addition.There were three QTL(qSH-1,qSH-3-3 and qSH-5)showing consistent additive effects at stages Ⅰ and Ⅱ.Breeding strategies for improvement of tolerance to low fertilizer stress in rice via marker-aided selection were discussed.
Abstract:
To investigate genotype×environmental temperature interactions for seed vitality QTL,a set of 282 F13 recombinant inbred lines(RILs)derived from a japonica/indica rice cross were assessed for four seed vitality traits,i.e.germination rate,radical length,plumule length and plumule dry weight,at three temperatures of 25,20 and 15℃,respectively.Using a linkage map with 198 marker loci,the main-effect QTL for the traits were mapped by composite interval mapping.A total of 34 QTL for the four seed vitality traits were identified.The majority(82%)of these QTL were clustered within five genomic regions designated as QTLqSV-3-1,qSV-3-2,qSV-5,qSV-8-1 and qSV-8-2,respectively.All of these five QTL had small individual effects on the traits,explaining only 3.1% to 15.8% of the phenotypic variation with a mean of 7.3%.QTL qSV-3-1,qSV-3-2 and qSV-8-1 showed almost consistent effects on the traits across all three temperatures while qSV-5 and qSV-8-2 had effects mainly at the normal temperatures of 20 and 25℃.This result indicated that there were significant genotype×environmental temperature interactions controlling seed vitality and these interactions appeared to be QTL-specific.All the five QTL identified showed effects on plumule length,suggesting that plumule length could be used as a good indicator to evaluate the level of seed vitality in rice.
Abstract:
Ammopiptanthus nanus is a rare and endangered species,native to desert habitats in Northern China.Allozyme diversity and population differentiation were evaluated for six natural populations using isoelectric focusing in thin-layer polyacrylamide slab gels.A total of 19 loci from eight enzyme systems were detected.An extreme low level of genetic variation was revealed both at the species level(A=1.21,P=21.05%,He=0.040)and at population level(P=14.04%,A=1.14(0.04),He=0.036(0.018)),which were lower than those of long-lived perennial woody and narrowly distributed species.Wright’s F-statistics analysis indicated a deficit of heterozygote both at population level(FIS=0.129)and at the total population level(FIT=0.202).A low level of genetic differentiation among populations detected(FST=0.085)was consistent with a high level of genetic identity among the populations(I=0.997).The history of bottleneck effect was speculated to be the main course for the current genetic structure in A.nanus.Consequently,conservation concerns of this species were discussed and conservation recommendations are suggested based on the results obtained from the study.Consequently,conservation of Keyieryongker(KE)population which maintained high genetic variability is recommended and this population could act as a source of transplant.
Abstract:
Aichi Hakusai(C1),which was a Chinese cabbage cultivar(Brassicarapa ssp.pekinensis(L.)Olsson)introduced from Japan,was used as plant material in this experiment.Investigations were carried out on histological and physiological changes during the process of in vitro shoot regeneration from cotyledonary explants.Histological observations showed that,(adventitious)shoots were induced through the pathway of direct organogenesis during the process of explants culture.Before adventitious shoots initiated,soluble protein content and activities of POD and SOD showed the trend to increase.As the cells were dedifferentiated,metabolism activity of cells gradually became stronger;enzymes activity and the soluble protein content were elevated.These results demonstrated that,morphological changes were strongly associated with physiological changes during the process of adventitious shoot induction.Addition of AgNO3 to the medium increased the activity of enzymes and promoted the differentiation percentage of(adventitious)shoots.
Abstract:
Histochemistry technique and phytochemistry methods were applied in the studies on the relationship between the structure where ginsenosides accumulated and the contents of total gypenosides in stem and leaf of medicinal plant Gynostemma pentaphyllum in different developmental stages.The results indicated that ginsenosides appeared color reaction from purple to light red when met special chromogenic agent,and the shade of color showed a positive correlation to the contents of ginsenosides in vegetative organs.In terms of leaf,ginsenosides distributed mainly in mesophyll tissue,the contents was higher in undifferentiated mesophyll than that in mature(tissue),while the effete leaf contained no ginsenosides.As to stem,ginsenosides distributed mainly in the external phloem parenchyma cells,much less in epidermis,assimilating tissue,(collenchyma)and phelloderm,and no coloration in xylem and pith parenchyma.The younger stem had a higher content of total gypenosides than that of mature and older stem,while rhizome,the storage organ,had the highest content.Within a plant,the accumulation of total gypinosides in the leaf occupied first place,the stem came second,and the current rhizome the highest in the same developmental stage.The idea that gypenosides accumulated in leaf,translocated in stem and storaged in rhizome and the suggestion of harvest were put forward in this paper.
Abstract:
The wood anatomy of Thuja sutchuenensis,an endangered plant endemic to China,is observed for the first time under optical and scanning electron microscopes.Growth rings are delineated by a narrow darker band of thick-walled latewood tracheids with abrupt transition from earlywood(EW)to latewood(LW).Longitudinal tracheids are relatively short with an average value of 1.61±0.22 mm in EW tracheids and 1.74±0.26 mm in LW tracheids.The bordered pits are mostly uniseriate,warty layer occasionally occurred on the pit margo.Cross fields are predominantly taxodioid with 2-6(8)pits.Xylem rays are mostly uniseriate with 1-11(2-5)cells in height and 65-70 rays per mm2 in density,among which nodular and indenture structure is apparent.The observation shows that the main characters of T.sutchuenensis wood are similar to those in other four species of this genus,providing evidence for the further investigation of T.sutchuenensis.
Abstract:
Holcoglossum auriculatum Z.J.Liu,S.C.Chen et X.H.Jin,a new species of Orchidaceae from Yunnan,is described and illustrated.This is a remarkable new species quite distinct from those known to us,including its ally H.subulifolium(Rchb.f.)Christenson,by having long-clawed sepals and petals,irregularly denticulate- or erose-margined petals and a peculiar lip which is elliptic-orbicular,shortly fimbriate or erose-fimbriate on the margins and clawed and auriculate at the base.
Abstract:
Larix chinensis,listed in Chinese Plant Red Data Book,is a typical endemic species in Qinling Mountain.It is the only tree species that structures the pure forest locates 2600-(3600 m),which has special functions to conserve water,firm mountain stone and maintain water and soil at the timberline area.We present a model for predicting the diameter at breast height(DBH)growth of L.chinensis.Data for this study were collected in Taibai Mountain Natural(Reserve),Shaanxi Province,China.Four samples of 40 m×40 m were investigated and every plant was stem-mapped.Species,DBH,total height,and crown length were recorded for each tree that had reached a diameter of 5 cm at breast height.Area potentially available index(APA),reflecting objectively the competition and growth pattern of L.chinensis,was selected in this paper.Taking subjective DBH and competition index as independent variables and the two yearly DBH relative growth rate as dependent variable,the growth model was established with good regression result.The r-value was 0.916 and the P value was less than 0.05.The model can simulate and predict the growth for L.chinensis efficiently.
Abstract:
Flowering phenology characteristic of Populus euphratica and Populus pruinosa in different populations was studied.The results showed that:flowering phenology of male trees was earlier than that of female ones in all populations of P.euphratica and P.pruinosa.Generally,the beginning of female bud burst time was 1-4 days later and the end was 2-5 days later than those of male bud burst time,respectively.The overlap period of male and female bud burst time was longer.In the same population,the inconsistency of inflorescence were relatively high among same gender of P.euphratica or P.pruinosa.Compared P.euphratica with P.pruinosa,flowering time of P.euphratica population was 2-5 days earlier than that of P.pruinosa.According to cumulative distribution of flowering individuals each day,the male and female bud burst time of P.euphratica was bimodal type,and that of P.pruinosa was unimodal type.
Abstract:
This paper reports natural growth course of Valeriana officinalis L.var.latifolia Miq.,an important medicinal plant and the statistic analysis results of pollination experiment.There are prominent difference on the kilo grain weight of the achenia between wild and tame fields under the same pollination circumstance.While in the same background of planting and running,there are prominent difference on the burgeon rates of the achenia between beekeeping and no-bees plots,even the former is about 4 size higher than the latter.By artificially culturing and increasing the number of pollination medium,the problem that the low burgeon rates and the tinpot quality of the achenia will be settled.Thereby it is possible to culture this plant in large-scale and realize the sustainable usage of its resource.
Abstract:
To find out the optimum harvest time for wild Isodon rubenscens in Qi County of Henan Province and introduced in Wuhan ,Guangshui of Hubei Province,we evaluated the yield and quality of I.rubenscens by the number of ramification,weight of leaves and content of rubescensine A of per-bundle plant.In addition,the effects of climate factors on yield and quality of I.rubenscens were analyzed.The results indicate that the effect of climate factors on the quality of I.rubenscens is not prominent,the content of rubescensine A in leaves of I.rubenscens in June reach approximate peak value in three areas.But climate factors have an effect on the yield of I.rubenscens,some of these factors can lead to the number of ramification on the plant in introduction areas is upwards to 2-4 times than the original area.To analysis all research results of the quality and yield of I.rubenscens,the optimum harvest time of I.rubenscens should be fixed ahead florescence.Therefore,the optimum harvest time of I.rubenscens is fixed from June to July in the introduced area-Guangshui of Hubei Province,and from June to August in the original area-Qi County of Henan Province.The studies can provide scientific basis for the Good Agriculture Practice of I.rubenscens.
Abstract:
Potamogeton malaianus is a dominant submersed aquatic macrophyte that has colonized the lakes across the middle and lower reaches of the Changjiang River.Vegetative reproduction is prevalent in P.malaianus and is highly visible,because of the extraordinary capacity of this plant to spread by fragmentation.Because of this,sexual reproduction has been considered of limited importance and little is known about the seed germination of this species.Laboratory studies were conducted on seeds of P.malaianus to determine the substrate,temperature and light requirements necessary for maximum seed germination.Seed germination was also examined in different duration of cold storage.The results showed that few 3-month-old whole seeds germinated in all treatments,but rose after the seed coats were cracked.Optimum germination occurred in a temperature of 25℃ and water substrate.Photoperiod significantly effected the seed germination.Seed retain viability for a short period in the cold storage condition,the highest germination occurred in 6-month storage seeds.The ecological implications of such behavior are discussed.
Abstract:
Using polyacrylamide gel electrophoresis(PAGE)to anlysis seed protein ingredients of 12 cultivars from four cultivated species in genus Cucurbita:C.moschato Duch,C.maxima Duch,C.pepo L.,C.ficifolia.The results showed:Among seed proteins extracted with water,0.5 mol·L-1 NaCl,0.1 mol·L-1 Lacetic acid and 70% Ethanol,most of them are salt-soluble proteins in C.ficifolia;In the other three cultivated species,most of them are water-soluble proteins,with little salt-soluble proteins;All of the four species have very little acid-soluble proteins;In the examination,no alcohol-soluble protein bandings were obtained.The maps of water-soluble proteins,salt-soluble proteins,acid-soluble proteins showed great difference among the four species,but there were almost no difference among the cultivars of the same specie.
Abstract:
Among various abiotic stresses,the salt stress is one of the most severe environmental factors responsible for the reduction of crop yield.With the development of molecular biology,the research of salt stress made great progress in gene cloning,analysis of its structure and gene expression.This paper reviewed small molecular osmotic substances,Late embryogensis abundant proteins,channel proteins,salt stress-related genes,signal transduction genes,transcriptional factors.Meanwhile prospects for the research are provided.
Abstract:
The vessel elements in rachis of Pteris vittata are observed and studied in this paper.The result shows that all of the vessel elements are very long.The scalariform perforation plates which are very long and gradient are in the either of end wall of vessel elements,there are a lot of perforations without pit membrane in these plates.The scalariform perforation plate in the P.vittata differs greatly from the scalariform pitting in side wall in conformation and structure.It is discussed that the vessel elements and the scalariform perforation plate in P.vittata.
Abstract:
This paper offers a method to measure leaf’s fractal dimension(FD)by introducing the box-counting dimension, one method the fractal theory provided.The scanned photos of mature leaves are treated according to the box-counting dimension.We use this method to measure the leaf’s FD of Osmanthus fragrans Lour.By analyzing the result, we find that:(1)The goodness of linear fit of double-logarithmic plot of the number of boxes to box size is significantly great:all the absolute values of coefficient of correlation are grcatcr than 0.999 1 that is very close to 1,the expectation.So we conclude that leases have typical fractal characteristics,which can be studied by fractal theory.(2)The FDs of all leaves of Tree 0.1 from the sample are between 1.7258 and 1.8880,with an average of 1.8065,a standard deviation of 0.0393 and a coefficient of variation(CV)of 2.7180%,which imply the low discreteness.A,nd all the data are normally distrilauted as vsrell.Other trees in the sample share the same case,so we conclude that the mature leaves of the same tree have the same FD statistically.(3)The ANOVA using rite completely randnm model shows that the differences between the 10 sample trees are not significant:F=0.706Osmanthus fragrans Lour share the same FD statistically.Therefore we presume that the mature leaves(or other mndule)of the same species share the same FD statistically.Finally we prnpnse an idea a, founding plant fractal taxonnmy.