Effectiveness of some management procedures for seed regeneration of plant genetic resources accessions

Procedures for seed regeneration of plant genetic resource accessions were investigated in terms of their effect on the variance effective population size and the probability that the initial allelic diversity is maintained after 10 and 20 cycles of regeneration. Four regeneration systems were compared: a bulk system (BL) where seeds are collected and treated in bulk, a partial sampling system (PS) where seeds are collected from not all, but some plants in the population with an equal number of offspring being raised from each sampled plant, a single seed system (SS) where accessions are regenerated so that each plant leaves one progeny, and the biparental mating system (BP) of Gale & Lawrence (1984) where plants are pollinated in pairs with one offspring being raised from each of the paired plants, or two offspring from one of the paired plants. It was shown that the relative efficiency of the four systems largely depends on the rate of selfing and that differences in the effective population size of the systems increase with increasing rates of selfing. The SS system gave by far the largest effective population size in regenerating the seed of moderately or highly selfing species. Although the BP system gave the largest effective size for outcrossing species, the SS system, when combined with selfing, gave a much larger effective size. The BL and PS systems were in no case the most effective. Of these two, PS system with a sampling fraction of 50% was as effective as BL, but less effective with a sampling fraction smaller than 50%. Calculations of the maintenance of the allelic diversity, however, revealed that differences between the systems are not appreciably large unless the accessions are regenerated over 10 or more cycles with 50 or fewer plants.     

Spatial and temporal patterns of vegetation recovery following sequences of forest fires in a Mediterranean landscape,Mt. Carmel Israel

The Mediterranean ecosystem of Mt. Carmel is subjected to increasing number of forest fires at various extents and severities due to increasing human activities. Accordingly, we tested whether in areas exposed to different fire histories vegetation regeneration is different in north versus south facing slopes, and the potential impact on erosion processes. Using remote sensing techniques we evaluated the Enhanced Vegetation Index (EVI) to monitor vegetation recovery following a single fire and three successive fires, using a series of Landsat images taken between 1985–2002. Following a single fire, vegetation cover reached pre-disturbance values within less than 5 years. Repeated fires caused further reduction of EVI values, especially at south facing slopes (SFS). The effects of three successive fires within 10 years, followed by a three year recovery period, however, are negligible when considering vegetation cover values. This was deduced as north facing slope EVI values returned to pre-disturbance conditions at the end of the 3 years and SFS EVI values to 80% of the pre-disturbance conditions. Our results indicate that Mediterranean eco-geomorphic systems are quite resilient, showing quick response, at least in terms of return to pre-disturbance states of vegetation cover, and hence of soil erosion rates. This is true not only in response to a disturbance caused by a single fire, but also for repetitive fire incidents.     

The relative use of abandoned farm clearings and old forest habitats by primates and a forest antelope at Tiwai, Sierra leone, West Africa

West Africa's high canopy forests have largely been replaced by a mosaic of active and abandoned agricultural fields. Use of the regenerating habitats by local fauna has not been well documented. I investigated the relative value of young successional forests, aged 5–12 years, and high forest, to primates and ungulates at Tiwai in West Africa. Four primates, Cercopithecus campbelli, Cercopithecus petaurista, Cercocebus atys, and Pan troglodytes, selected regrowth habitats more often than expected, and three primates, Cercopithecus diana, Colobus polykomos, and Procolobus badius, selected high forest habitat. The Maxwell's duiker Cephalophus monticola used both habitats equally.

The Cercopithecus spp. exhibited seasonal fluctuations in abundance in the two habitats, presumably in response to different fruit availabilities. The old forest supported a greater diversity and biomass of primates per unit area compared to regrowth habitats. The high forest was more valuable to the primate community, but young forests were also used by resident fauna, suggesting potential for management as wildlife habitat.     

甘薯（Ipomoea batatas (L.) Lam.）及其近缘野生种原生质体的植株再生

对甘薯品种高系14号及其近缘野生种I.triloba L、和I.lacunosa L,进行原生质体植株再生研究。从离体培养植株的叶柄分离出原生质体,将其培养在含有0.05mg/L 2,4-D和0.5mg/L激动素(KT)的MS培养基中,从原生质体获得了高频率的愈伤组织。培养8-12周后,将直径达2—3mm的小愈伤组织转移到添加0.05mg/L 2,4-D的MS培养基上。转移3-6周后,将愈伤组织进一步转移到添加吲哚乙酸(IAA)和6-苄基嘌呤(BAP)的MS培养基上,一些愈伤组织再生出植株。未再生植株的愈伤组织进一步在MS基本培养基上培养,它们也再生出植株。本研究从I.triloba原生质体获得高频率的植株再生;首次从I.lacunosa原生质体再生出植株;从高系14号原生质体也再生出完整植株。     

光敏核不育水稻（31301s）原生质体培养再生成株

从光敏核不育水稻３１３０１ｓ胚性细胞悬浮系分离培养原生质体，成功地实现了植株再生，原生质体在ＫＰＲ培养基中植板率达２．４％，在ＳＫＰＲ（除去ＫＰＲ中复杂的有机成分，以及葡萄糖以外的糖类）中获得了较高的植板率（１．８％），在高压灭菌取代过滤除菌的ＳＫＰＲ中也能培养成功。３１３０１ｓ原生质体再生细胞团直接分化的分化率达１０％，再生细胞团在含３％蔗糖和５００ｍｇ／Ｌ脯氨酸的Ｎ６培养基上增殖后再分化，可明     

Isolation and culture of grape vine cv. Chardonnay leaf protoplasts

Summary Experimental conditions were established that resulted in high yields and good viability of the protoplasts obtained from leaves of Vitis vinifera, cv. Chardonnay regenerated in vitro by somatic embryogenesis. The effect of factors of the culture medium and various environmental conditions upon the frequency of cell division has been examined, and a method of culture is described by which protoplasts were induced to begin division. Most protoplasts obtained in this way regenerated cell walls within the first few days and cell division occurred after 10 days of culture in a liquid medium. Some cells have divided two or even three times. Nevertheless, the cells did not continue dividing beyond this stage.     

Plant Regeneration and Genetic Variability from Tissue Cultures of Sunflower (Helianthus annuus L.)

Adventitious buds were induced from in vitro culture of sunflower (Helianthus annuus L.) cotyledons. Four inbred lines (G1, G2, G3 and HA89), an open pollinated variety (‘Argentario’) and two hybrids with specific genetic markers were used. Cotyledons were cultured in vitro on MS medium (Murashlge and Skoog 1962) containing various concentrations of kinetin and indole 3-acetic acid (IAA). The quantitative interactions between auxin and cytokinin, the age of the cotyledons and the 2,3,5-triiodobenzoic acid (TIBA) treatments have been found to influence shoot regeneration. The plantlets, after rooting, were successfully established on soil. Qualitative variation was noted in self-pollinated progeny of plants regenerated from culture of two inbreds. Chimerism in regenerated plants was indicated by sectoring of the genetic markers. Some culture-induced variant phenotypes were similar to known spontaneous mutation in sunflower but others have been not yet described. Preliminary data indicate that most of them may have single-gene recessive inheritance.     

Plant regeneration from protoplasts isolated from primary calli using mature embryos of two Brazilian rice cultivars

A plant regeneration system from rice protoplasts using calli derived from mature embryos was established for the two Brazilian modern rice cultivars IAC-201 and IAC-165. After 30 to 40 days of in vitro culture it was possible to obtain on average 6 million protoplasts per gram of callus. Microscopic selection of embryogenic calli was a key step for protoplast isolation. The production of embryogenic calli increased when L-proline and casein hydrolysate were used in the callus induction medium. The Oc or IR52 nurse cell lines were essential for protoplast division. Different regeneration media were studied and 139 plants were regenerated which set seed. Some of the regenerated plants showed morphological variation such as the presence of awns in spite of the short time of the in vitro culture. This revised version was published online in July 2006 with corrections to the Cover Date.     

Coffee biotechnology and its application in genetic transformation

The most important advances obtained on in vitro coffee regeneration systems and in coffee genetic transformation, drawing perspectives and scopes to further studies in these fields are presented and discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

棉花组织培养高效植株再生体系的建立

通过对影响棉花体细胞胚胎发生和植株再生关键因素的研究,建立了适用于广泛基因型的棉花组织培养高效胚胎发生与植株再生体系。从中棉所12、中棉所19、泗棉3号等20余个主栽品种诱导获得了胚胎发生和植株再生,有效地突破了棉花组织培养植株再生的基因型控制,使占我国棉田面积50%以上的品种均能诱导获得胚胎发生和再生植株。首次诱导获得直接胚胎发生,使棉花组织培养的周期由180d缩短到120d左右,减少了培养过程中变异的发生。该结果的获得必将大大促进植物细胞工程和基因工程在棉花遗传改良上的应用。