利用TUNEL检测、细胞学及细胞化学方法，对毛竹茎秆纤维细胞发育过程中的细胞程序性死亡进行了研究。在次生壁形成的早期，纤维细胞出现染色质凝聚、细胞器膨胀、液泡膜解体和细胞质泡状化等典型的细胞程序性死亡形态学特征；TUNEL检测反应呈阳性，显示此时的纤维细胞核DNA发生了片段化。此时，在纤维细胞裂解的液泡膜、降解的细胞质和凝聚的染色质上具有ATPase活性。纤维细胞质的Ca2+水平会随着次生壁的形成而逐渐升高，随后Ca2+聚集成块状。在初生壁形成后期，纤维细胞染色质上的酸性磷酸酶（APase）活性增强。随着纤维次生壁的持续增厚，ATPase、酸性磷酸酶和Ca2+将在裂解的细胞质和凝聚的染色质上持续存在多年。结果表明，毛竹茎秆纤维细胞的次生壁形成过程是一个主动自溶的细胞程序性死亡过程。初生壁形成后期染色质上酸性磷酸酶活性增强及次生壁形成期胞质Ca2+的聚集，与纤维细胞的程序性死亡密切相关。ATPase, Ca2+和 APase参与了纤维细胞程序性死亡过程中原生质体的降解。
The floral organogenesis of Reineckia carnea (Convallariaceae) was observed under scanning electron microscope. The tepal and stamen primordia of Rcarnea initiated in a reversed unidirection type. The tepals, partly fused with filaments, formed a short tube at the late stage. Carpel primordia initiated, which overlapped by tepal and stamen primordia, by the same pattern, then fused into a syncarpous gynoecium. The flowers on the tip of inflorescences were prone to vary in floral organ numbers. Considering the floral organogenesis traits of Rcarnea in early stages and floral organ number variation, tepals and stamens should differentiate from common primordia. Characters of the floral organogenesis pattern and perianth tube formation time of Reineckia, Speirantha and Convallaria, revealed that Convallaria was more derived among them, and Speirantha was more primitive than Reineckia.
The ultrastructural research reveals that the spermatogenesis of the fern Pteris fauriei undergoes the de novo occurrence of the motile organelles, including the blepharoplast, multilayered structure and flagella, the formation of the coiled mitochondrion and nuclear shaping, and finally forms a spiral spermatozoid, which resemble other homosporous ferns described. Some new phenomenon or details during spermatid differentiation in present study including: Spermatids show polar differentiation in the early stage, the nucleus lies in the proximal end (the end of cell plate formation in mitosis), and the blepharoplast, mitochondria and plastids mainly located in the distal end. Abundant microtubules extend from the blepharoplast and plenty of radial mitochondria surround the blepharoplast. The differentiation of the basal bodies undergoes 3 stages, ie. procentriole, centriole and basal body. Their internal structures show different patterns, which are the tubular pattern, cartwheel pattern, and stellate pattern respectively. The amorphous material in the blepharoplast is considered to be the microtubule organizer, from which the multilayered structure, the accessory microtubular ribbon and flagella are differentiated. Abundant membranous structures are produced in the course of spermatid differentiation, which may be used as envelope materials in nuclear shaping. This study reveals some details during spermatogenesis of the fern Pteris fauriei, which contributes to understand the mechanism of spermatogenesis.
Basidiospores of Agrocybe salicacola were collected from a mature fruiting body by ejection. 224 singlespore strains were isolated respectively by dilution separation method, 210 were identified as monocaryons. The result of mating test suggested that the sexinheritance of Asalicacola is tetrapolar heterothallism. Four different matingtype strains were acquired by mating test, and the ratio of AxBx∶AxBy∶AyBx∶AyBy of monocaryotic strains was 47∶59∶53∶51. The results showed that the number and distribution of its mating types was related with spore germination, growth rate of spore germination and mycelium growth. In four mating type strains, the growth rate of one mating type strains was more slow than other three, and only there were 3 and 5 slowgrowing strains in other two mating type strains. Especially, although the growth rates between the FastFast mating heterocaryotic strains and FastSlow mating heterocaryotic strains in YPD plate were primarily same, but the differences in cultivation bag were obvious. The growth rate genes may be linkaged with mating factors A and B. In breeding of mushroom, most scientists may select FastSlow mating heterocaryon, so distorted segregation of mating types may happen.
Viable egg cells, synergids, central cells and zygotes of lettuce (Lactuca sativa L.) were isolated using enzymatic digestion and mechanical dissection. The ovaries were digested in enzymatic solution for 40-50 min, and then transported into the isolation solution without enzymes to dissect. In the dissected embryo sacs, the outline of an egg cell, two synergids and a central cell could be observed. When dissected embryo sacs were sliced from the chalazal end, four cells could be released by gently pushing its micropylar end. In optimal condition, 29 embryo sacs and 11 egg cells could be isolated from 40 ovaries during 90 min. The isolated egg cells could be collected using micromanipulator for preparation of molecular biology of egg cell of lettuce. The isolation of egg cell of lettuce will make a great chance for in vitro fertilization in a dicot plant.
Petrocosmea shilinensis, a new species of Gesneriaceae, is described and illustrated. The new species was collected at Guishan region of Shilin County, Yunnan Province in 2008. It is different from its similar species Psericea , in its cordate base of leaf, retrorse indumentums on petioles and the abaxial surfaces of leaf, geniculate filaments with dense ca. 15 mm long beardlike indumentums in the middle.
Based on fieldwork and specimen examination,Gastrochilus fuscopuntuatus and Oberonia pumila were treated as synonyms of Gastrochilus pseudodistichus and Oberonia insularis respectively. Gastrochilus somai was recognized as a distinct species, differing from Gastrochilus japonicus by the larger plant, subumbellate inflorescence, and slippershaped hypochile. Four species, Bulbophyllum gyrochilum, Dendrobium praecintum, Peristylus superanthus and Sunipia angustipetala, are represented as new records from China.
This work aimed to study the role of plant vitrification solution 2 (PVS2) on seed germination, and the effect of rapid freezing and vitrification treatment on seed cryopreservation of the wild mature seeds of Dendrobium chrysanthum, an endangered orchid species. The results indicated that the seeds germination decreased with increasing treatment time of PVS2. Cryotolerance of seeds was obviously increased by PVS2 pretreatment. When pretreatment time was below 45 min, seeds cryotolerance increased with increasing pretreatment time of PVS2, while it decreased after 60 min. The survival seeds could germinate and develop into normal seedling after storage in liquid nitrogen. In conclusion, mature Dchrysanthum seeds could be successfully cryopreserved after 45 min pretreatment with PVS2.
In this research, tuberlike galls which induced by thrip on ivy tree leaves were chosen as materials, and the physiological responses as well as partitioning of mineral nutrition, soluble protein and saccharide contents in galled and ungalled tissues were assayed. Results indicated that compared to the ungalled tissues, galling tissues decreased in many physiological indexes including hydrogen peroxide concentration, Peroxidase and phenylnine amonialase activities and the contents of malondialdehyde. Galling tissues decreased in photosynthetic rate but increased in respiratory rate. Galling tissues acted as a nutritive sink that accumulate more nutrition than surrounding ungalled tissues. Phytohormones and insects extracts alone can not induce the formation of galls, but cytokinins such as kinetin, 6BA and Zeatin can induce responses which are similar to the earlier response of thrip feeding.
The changes of molecular species in membrane lipids during coldacclimation (CA) in winter and spring cultivars of rapeseed (Brassica napus) were profiled with ESIMS/MS based lipidomics. The membrane fluidity, the critical properties for plants to tolerate freeing injuring, was examined with double bond index (DBI) and carbon number of the fatty acid of the glycrolipid. The results indicated that the molecular composition of membrane lipids in the two cultivars under both normal growth condition and CA were similar to that of Arabidopsis reported previously and that DBI in spring cultivar accumulation subtly more than that in winter cultivar. The results suggested that CA of rapeseeds needs more than 3 days and that spring cultivar were more sensitive to CA, which was confirmed by the CAinduced proline accumulation.
The floral homeotic gene APETALA1 (AP1) specifies floral meristem identity and sepal and petal identity in Arabidopsis. GUS staining showed that the expression of AP1 mainly focus on shoot apex, sepal and petal, floral meristem, junction of siliques and pedicels. Sequence analysis showed that numerous ciselements were found in the AP1 promoter, including the Wbox, which indicated the regulated expression of AP1 by certain transcriptional factors. 21 independent wrky single mutants did not affect the expression of AP1 in inflorescence, however, mutation of AP1 enhanced the basal expression of seven WRKY genes among the 10 genes checked. This result implied that AP1 may participate in the basal resistance of flower through controlling the development of both sepals and petals.
The effects of different drying rate on desiccation tolerance and ntioxidant enzyme activities of Baccaurea ramilfora seeds were studied in this paper. The initial water content(WC) of Bramilfora seeds was high 172 g H2O·g1DW, and germination was 8667%, respectively. When the seeds dehydrated to the same water content (0.90g H2O·g1DW), the germination of seeds increased with slwodehydrated method ( 9778%), while decreased with rapiddehydrated method ( 6444%). The germination of rapiddehydrated seeds with 076 g H2O·g1DW WC was 2167%, while that of slowdehydrated seeds with 068 g H2O·g1DW WC was 5556%. The Bramilfora seeds were recalcitrant seeds which showed higher tolerance to slow dehydration. Both of relative electrolyte leakage and lipid peroxidation increased following hedehydration, and the increase rate of slowdehydrated seeds were slower than rapiddehydrated seeds. Among these antioxidant enzymes, the activities of SOD, DHAR and APX were higher in rapiddehydrated seeds than slowdehydrated seeds, while CAT was lower, and GR was not found. These results indicated that CAT played more important role in desiccation tolerance of Bramilfora seeds than the other antioxidant enzymes.
In this paper, we described fruit and seed traits of 145 tree species from a 20 ha tropical seasonal rainforest dynamics plot. The fruiting of most tree species occurred in rainy season(7103%). Fewer species had fruit in dry season. Flesh fruits, such as drupes, capsules and berries, were very common in the plot and, fruits were mainly black, yellow and brown colored. Most species were animal dispersed(5655%). Species with large seeds(maximum seed length >10 mm)were predominate(5310%), followed by mediumsized seeds(2-10 mm), and small seeds(<2 mm in length). Seed mass varied from 23×105 to 2229 g, the majority of species(7655%) produced seeds with a mass ranged from 001 to 10 g. The mass of seeds collected exhibited a significant seasonal changes. Seeds collected in rainy season were heaver than seeds collected in dry season. Unassisted dispersal species tended to have large seed, and species dispersed by wind tended to have small seeds. A significant positive correlation was found between the seed mass and maximum DBH of the species.
A new iridoid, named plumieride B, was isolated from the leaves of Neolamarckia cadamba, together with a known iridoid. The new structure was determined to be Δ13,14plumieride by spectroscopic methods especially 2DNMR analysis.
