Physiological integration among ramets of Lathyrus sylvestris L.

Summary Lathyrus sylvestris is a pioneer legume often found in disturbed habitats. Mainly reproduced through vegetative propagation, this clonal species presents a system of ramets that remain connected for several years. The existence of carbon transfer among ramets within a clone has been studied using ¹⁴C in situ. Assimilate translocation from primary to secondary ramets was observed in all clones when the primary ramet was exposed to ¹⁴CO₂. The amount of transfer ranged from trace up to 90% of the total ¹⁴C incorporated. However, in only half of the clones there was consistent enrichment of the secondary ramet (5 to 89%) suggesting that interramets transfer of carbon may be facultative. Furthermore, when significant export occurred from the primary ramet, it was always principally towards only one ramet even when the clone included more than one. The transfer of ¹⁴C from secondary to primary ramets was shown to be significant only when photosynthesis of the latter was decreased by shading. In this case import of carbon was never more than 60% of the incorporated ¹⁴C.No correlation was found between age or size of the ramets and the intensity of transfer. The shading effect let suppose that transfers are mainly driven by carbon limitation due to changing environmental conditions and not to the state of ramet maturity. The adaptative advantage of such facultative physiological integration between ramets of a clone is discussed.     

Chromosomal instability in Lathyrus sativus L.

Summary In Lathyrus sativus (2n=14), variety LSD-1 shows an instability of somatic chromosome number which can be observed in root tip and shoot tip mitoses. In this variety, approximately 54% of the seedlings showed intra-individual variation in chromosome number ranging from 2n=14–3. This variability in chromosome number was recorded in approximately 60% of the dividing cells. Two seedlings were triploid with 21 chromosomes. Variation in chromosome number in somatic cells within individual plants is possibly controlled by genetic factors, which result in spindle abnormalities, chromosome degradation and minute chromosomes. The variation in chromosome number is probably responsible for the pollen polymorphism noted in this particular strain. The possible mechanism of intra-individual variability and the occurrence of the phenomenon vis-a-vis its applications are discussed.     

胁迫处理对林生山黧豆蛋白质多肽及其含量的影响

应用二维电泳技术,分析了经水分胁迫（ＰＥＧ）、盐分胁迫（ＮａＣｌ）和热激（４０℃）处理后林生山黧豆（ＬａｔｈｙｒｕｓｓｙｌｖｅｓｔｒｉｓＬ．）体内蛋白质多肽及其含量的变化。有些蛋白质经ＰＥＧ、ＮａＣｌ和热激处理后可以产生相同的变化。两种不同的胁迫因子对某些蛋白质的影响有一定的共同性。特定的胁迫条件可以造成特定的影响。不同胁迫因子对同一蛋白质多肽可以造成不同的影响。胁迫下蛋白质的变化可能与林生山黧豆抵抗和适应胁迫条件的能力以及体内非蛋白质氨基酸的代谢有关     

Transgenic grasspea (Lathyrus sativus L.): Factors influencing Agrobacterium-mediated transformation and regeneration

A reproducible procedure was developed for genetic transformation of grasspea using epicotyl segment co-cultivation with Agrobacterium. Two disarmed Agrobacterium tumefaciens strains, EHA 105 and LBA 4404, both carrying the binary plasmid p35SGUSINT with the neomycin phosphotransferase II (nptII) gene and the -glucuronidase (gus)-intron, were studied as vector systems. The latter was found to have a higher transforming ability. Several key factors modifying the transformation rate were optimized. The highest transformation rate was achieved using hand-pricked explants for infection with an Agrobacterium culture corresponding to OD₆₀₀0.6 and diluted to a cell density of 10⁹ cells ml^–1 for 10 min, followed by co-cultivation for 4 days in a medium maintained at pH 5.6. Putative transformed explants capable of forming shoots were selected on regeneration medium containing kanamycin (100 g ml^–1). We achieved up to 36% transient expression based on the GUS histochemical assay. Southern hybridization of genomic DNA of the kanamycin-resistant GUS-expressive shoots to a gus-intron probe substantiated the integration of the transgene. Transformed shoots were rooted on half-strength MS containing 0.5 mg l^–1 indole-3-acetic acid, acclimated in vermi-compost and established in the experimental field. Germ-line transformation was evident through progeny analysis. Among T₁ seedlings of most transgenic plant lines, kanamycin-resistant and -sensitive plants segregated in a ratio close to 3:1.     

山黧豆幼苗对干旱胁迫的生理响应

用PEG6000模拟干旱对山黧豆进行胁迫。结果发现,胁迫初期（0~48 h）,突然的水分亏缺使气孔导度（Sc）和蒸腾速率（Tr）迅速下降,而净光合速率（Pn）和水分有效利用率（WUE）基本维持稳定。胁迫后期（48~108 h）,上述四个光合指标均不同程度地向对照水平恢复;脯氨酸和相对电导率（REC）受胁迫强度影响较小,但与胁迫时间呈明显正相关,分别在48和60 h增幅最大,而且当REC上升至对照的50%左右时,脯氨酸含量已达对照的14倍之多。由此认为,山黧豆可能主要通过迅速减小Sc和Tr以及大量而急剧的积累脯氨酸来减轻干旱所造成的伤害。     

林生山黧豆幼苗2,4—二氨基丁酸的合成及其与胁迫条件的关系

林生山黧豆幼苗用［3H］－天门冬氨酸标记后,高丝氨酸在6h内迅速增加。高丝氨酸合成速率降低后,2,4－二氨基丁酸的合成量上升,于18h达到高峰。赖氨酸和苏氨酸与二氨基丁酸的合成表现有协同反馈机制。结果支持了天门冬半醛转氨生成二氨基丁酸的假说。盐胁迫、渗透胁迫和热激增加了二氨基丁酸的合成,可能是因为不同胁迫条件都造成了细胞脱水,从而促进了二氨基丁酸的合成。     

Effects of europium ions (Eu3+) on the distribution and related biological activities of elements in Lathyrus sativus L. roots

Scanning electron microscopic and energy-dispersive X-ray analyses were used to study the distributions of different types of elements in the epidermis, exodermis, endodermis, and vascular cylinder of the fracture face in the Lathyrus sativus L. roots in the presence or absence of Eu³⁺. Some index of the biological activity related to the elements binding with protein were determined also. The results showed that the tissular distributions of elements in the fracture face are different in the presence and absence of Eu³⁺. The atomic percentages of P, S, Ca, and Mn were influenced more than those of other elements. Eu³⁺ promoted the biological activities of various kinds of element. The one possible mechanism changing the biological activities was that the reaction of Eu³⁺ Eu²⁺ would influence the electron capture or transport in elements of binding protein. Another mechanism was that CaM-Ca²⁺ becoming CaM-Eu³⁺ through Eu³⁺ instead of Ca²⁺ would affect the biological activity of elements by regulating the Ca²⁺ level in the plant cell.     

Shoot elongation in Lathyrus odoratus L.: Gibberellin levels in light- and dark-grown tall and dwarf seedlings

The levels of gibberellin A₁ (GA₁), GA₂₀, GA₁₉, GA₈, GA₂₉ and GA₈₁ (2-epiGA₂₉) were measured in tall (L-) and dwarf (ll) sweet-pea plants grown in darkness and in light. In both environments the apical portions of dwarf plants contained less GA₁; GA₈ and GA₁₉, but more GA₂₀, GA₂₉, and GA₈₁ than did those of tall plants. It is concluded that the partial block in 3β-hydroxylation of GA₂₀ to GA₁ is imposed by allele l in darkness as well as in the light. Furthermore, darkness does not appear to enhance elongation in sweet pea by increasing GA₁ levels. The reduction of the pool size of GA₁₉ in dwarf plants supports recent theories on the regulation of GA biosynthesis, formulated on the basis of observations in monocotyledonous species. Darkness results in decreased GA₂₀, GA₂₉, and GA₈₁ levels in the apical portions of tall and dwarf plants and possible reasons for this are discussed.     

Effects of Eu3+ on the metabolism of amino acid and protein in xerophytic Lathyrus sativus L.

The contents of amino acids and proteins and the activity of Na⁺, K⁺-ATPase were determined in roots, stems, and leaves of Eu³⁺-treated Lathyrus sativus L. The results showed that the treatment of Eu³⁺ made the contents of amino acid and protein and the activity of Na⁺, K⁺-ATPase change. The first possible mechanism was that Eu³⁺ directly made the electric potential of −NH₂ or −COOH of amino acid change. The second possible mechanism was that Eu³⁺ played a role in metallic-activated factors of certain enzymes, which catalyze the catabolism and anabolism of protein. Then, the contents of amino acids and proteins were relatively changed. The third possible mechanism was that Eu³⁺ regulated the activity of ATPase through changing the Na⁺/K⁺ ratio. The energy released by ATPase was the driving force for the translocation of amino acids and proteins in the plant cell. Because of the changeability of its valence, Eu played an, important role in regulating certain physiological reactions to increase the adaptability of L. sativus in arid environment. These authors contributed equally to this work.     

In vivo and in vitro flowering response of chicory (Cichorium intybus L.): influence of plant age and vernalization

Chicory plants (Cichorium intybus L. var foliosum cv Flash) were tested with and without a 4-week-long cold treatment for in vivo and in vitro flowering potential every 2 weeks during the growing season. One hundred percent of the plants harvested 112 days or later after sowing and then vernalized flowered in vivo. In vitro, no vernalization was needed to initiate flowering-stems on chicory explants taken from roots of 100 days old and older. 5-Azacytidine, a DNA demethylation agent, increased the flowering percentage on explants from young, vernalized roots but could not induce more than 15% flowering on young, nonvernalized roots. The greater flowering potential of chicory root explants in vitro when compared to plants of the same age tested in vivo was clearly established. This result suggests that some negative control on flowering was removed when root explants were excised and the main plant body discarded. Received: 31 August 1998 / Revision received: 27 October 1998 / Accepted: 10 November 1998     

Mapping loci controlling vernalization requirement in Brassica rapa

Brassica cultivars are classified as biennial or annual based on their requirement for a period of cold treatment (vernalization) to induce flowering. Genes controlling the vernalization requirement were identified in a Brassica rapa F₂ population derived from a cross between an annual and a biennial oilseed cultivar by using an RFLP linkage map and quantitative trait locus (QTL) analysis of flowering time in F₃ lines. Two genomic regions were strongly associated with variation for flowering time of unvernalized plants and alleles from the biennial parent in these regions delayed flowering. These QTLs had no significant effect on flowering time after plants were vernalized for 6 weeks, suggesting that they control flowering time through the requirement for vernalization. The two B. rapa linkage groups containing these QTLs had RFLP loci in common with two B. napus linkage groups that were shown previously to contain QTLs for flowering time. An RFLP locus detected by the cold-induced gene COR6.6 cloned from Arabidopsis thaliana mapped very near to one of the B. rapa QTLs for flowering time.     

Gibberellic-acid causes flowering in the short-day plants Panicum miliaceum L., P. miliare lamk., and Setaria italica (L.) P. Beauv.

Treatment with gibberellic acid (GA₃) causes formation of flowers in Panicum ciliaceum and Panicum miliare, two short-day plants, under long days (continuous light), and hastens the emergence of ears in Setaria italica, a quantitative short-day plant, under both inductive and non-inductive photoperiods. The GA₃-induced inflorescences, however, remain short and bear only few spikelets; in the two Panicum species, the spikelets also remain sterile.     

光周期对穗花狐尾藻生长、开花与种子形成的影响

通过人工补光和遮光处理,初步研究了光周期对狐尾藻生长和开花的影响。研究发现:8h短日照条件不利于狐尾藻的生长和花序形成,导致狐尾藻不能正常开花和结实;与自然日照长度(平均日照14h)条件下相比,16h长光照条件可以增加植株的高度和分枝数,形成更大的生物量;但24h全光照条件对生长有抑制作用。长光照条件下,狐尾藻花序形成时间和开花时间均比自然条件下延迟,形成花序的数目也显著较自然条件下的少,但长光照条件下形成的种子比自然条件下形成的种子具有更高的萌发率。     

Plant regeneration from stem-derived callus of the seed legume Lathyrus sativus L.

Callus cultures from stem explants of six Lathyrus sativus L. cultivars were tested for their morphogenic capacity. Shoot-buds were formed in calli of only one cultivar. Maximum response was observed in the medium containing 10^-8 M picloram and 10^-6 M benzylaminopurin. Supplementation with adenine sulphate was required for shoot-bud formation. The greatest frequency of shoot-bud formation was detected at the second passage and complete lack of regeneration capacity was observed after the 8th passage. Cell regenerates were diploid.     

Mutant dn Influences Dry Matter Distribution, Assimilate Partitioning and Flowering in Lathyrus odoratus L.

The flowering mutant dn in sweet pea was used as a tool to study¹⁴C-assimilate and dry matter partitioning with respect to nutrientdiversion theories on the control of flower initiation. Wildtype plants (Dn^h) are photoperiodic and exhibit late floweringand profuse basal branching in short days while mutant plants(dn) are day neutral, early flowering and devoid of basal laterals.In short days, dn plants exported a significantly greater proportionof assimilate acropetally than (Dn^h) plants and the upper portionof dn plants had a greater dry weight. These differences werereduced dramatically when basal laterals were excised regularlyfrom the (Dn^h) plants although the difference in flowering remained.However, the effect of dn on resource allocation within theapical region may be more important in regard to flowering thanthe effect on acropetal versus basipetal movement. In shortdays, the dn plants partitioned significantly more resourcesinto their internodes and petioles, and less into their leaflets,than Dn^h plants as shown by dry weight and ¹⁴C-assimilate measurements.These differences were apparent from as early as node 7 up tothe node of flower initiation in dn plants (node 30) and theywere not eliminated by removal of basal laterals from Dn^h plants.Differences between dn and Dn^h plants in partitioning and floweringwere largely eliminated under long days. The fact that in thisspecies a single gene influences both resource allocation andflower initiation lends further support to nutrient diversionhypotheses on the control of flowering. Key words: Assimilate partitioning, branching, flowering, mutant, sweet pea     

A Comparison of the Flowering and Branching Control Systems in Lathyrus odoratus L. and Pisum sativum L.

In the sweet pea (Lathyrus odoratus L.) the difference in floweringbehaviourbetween photoperiodic (long-day) and day-neutral cultivars appearsto be due to a difference in their ability to produce a graft-transmissiblefloral inhibitor. The flowering control systems in the sweetpea and the garden pea (Pisum sativum L.) appear to be verysimilar on the basis of inter-generic graft results. It is suggestedthat the major flowering genes Dn* in L. odoratus and Sn andDne in P. sativum control steps in a biochemical pathway commonto these two species (which are related at the tribal level)and that the product of this pathway inhibits flowering andpromotes outgrowth of basal laterals in both species.     

History and traditional cultivation ofLathyrus sativus L. andLathyrus citera L. in the Iberian peninsula

Recent ethnographic research carried out in Spain has allowed the cultivation ofLathyrus sativus L. andL. cicera L. to be documented. Both species already appear in the Spanish archaeological record. Grown under traditional farming systems,L. sativus L. andL. cicera L. are still used for human consumption (onlyL. sativus L.) and both are used for fodder. Data on cultivation history, fanning practices, crop processing sequence and uses are here presented, which will enable a better understanding of their possible roles in prehistoric times.     

High-frequency plant regeneration by <Emphasis Type="Italic">in vitro</Emphasis> shoot proliferation in cotyledonary node explants of grasspea (<Emphasis Type="Italic">Lathyrus sativus</Emphasis> L.)

Summary Multiple shoots were induced from cotyledonary nodes of grasspea (Lathyrus sativus L.) derived from 7-d-old in vitro seedlings on Murashige and Skoog (MS) medium containing N⁶-benzyladenine (BA), kinetin, or thidiazuron, BA being the most effective. Among the five genotypes tested, shoot proliferation frequency was the highest (93.3%) for IC-120487, giving the maximum number of shoots (11.3 shoots per explant) on MS medium augmented with 2.0 mgl⁻¹ (8.87 μM) BA. Shoot cultures were established by repeatedly subculturing the original cotyledonary nodes on fresh medium after each harvest of the newly formed shoots. Thus 30–40 shoots were obtained in 2 mo. from a single cotyledonary node. Up to 81.8% of the shoots developed roots following transfer to half-strength MS medium containing 0.5 mgl⁻¹ (2.85 μM) indole-3-acetic acid. Plantlets were successfully acclimatized and established in soil.     

山黧豆毒素ODAP的生物合成及与抗逆性关系研究进展

有关山黧豆毒素ODAP的生物合成途径的前体物和合成程序已经证实,但其关键合成酶尚未分离与鉴定,因而无法克隆相应基因和利用反义RNA技术以控制其生物合成。研究表明,利用相应的抑制剂控制ODAP生物合成前体物可降低ODAP的积累量。山黧豆中ODAP含量与其抗逆性之间密切相关,这与其能有效地清除山黧豆中·OH自由基有关,外源ODAP处理获同样效果。此外,因ODAP既是含氮化合物,又是游离氨基酸,极易溶于水,可在逆境胁迫下与脯氨酸和多胺一样大量而迅速地积累,推测它也可能作为细胞渗透调节物质和防脱水剂,并在氮代谢和能量代谢方面起重要作用。对今后该领域的重点研究方向也进行了探讨。     

Low-temperature acclimation of barley cultivars used as parents in mapping populations: response to photoperiod,vernalization and phenological development

Six barley (Hordeum vulgare L.) accessions, previously used as parents of mapping populations, were evaluated for characters potentially affecting the location of low-temperature (LT) tolerance QTLs. Three were of winter growth habit (Kompolti Korai, Nure, and Strider), one was facultative (Dicktoo) and two were spring (Morex and Tremois). Final leaf number (FLN) and LT₅₀ were determined at weekly intervals from 0 to 98 days of LT acclimation/vernalization under both long day (LD) and short day (SD) photoperiods. The point of vegetative/reproductive transition was determined from measurements of double ridge (DR) formation and FLN. With the exception of Nure, SD delayed development by increasing leaf production. Dicktoo was extremely SD sensitive lengthening its vegetative phase by more than 63 days relative to the LD photoperiod. SD had the opposite effect on Nure, causing an accelerating of flowering exhibiting the characteristic of ‘short day vernalization’. All accessions except Dicktoo and Kompolti Korai acclimated rapidly in the first 7 days of LT exposure, approaching their maximum LT tolerance in 14–21 days. Dicktoo and Kompolti Korai continued to slowly acclimate until reproductive transition. The results emphasize two important points: (1) the location of QTLs for LT tolerance, and as a consequence the identification of putative candidate genes, will be a function of the genotypes sampled, the experimental conditions used, and the quality of the phenotypic data and (2) the barley LT tolerance pathway reaches an early impediment relative to closely related more hardy members of the Triticeae such as wheat and rye.