“伊丽沙白”甜瓜子叶组织培养研究

以甜瓜品种伊丽沙白为试材,研究了甜瓜子叶外植体在不同激素组合的诱导分化培养基中的分化频率,旨在建立适于遗传转化的甜瓜子叶快速高频再生系统,为遗传转化的研究及生物技术育种提供理论依据。

黄萎病菌毒素诱导棉苗子叶组织磷素外渗规律初探

本研究采用黄萎病菌毒素处理棉苗子叶圆片,结果表明毒素处理后的棉苗子叶组织的磷素外渗量明显提高,随着毒素处理浓度的提高,磷素外渗量总体上有逐渐提高的趋势。相关分析明表明:磷素相对外渗率与黄萎病指呈显著正相关,相关系数R为0 949、决定系数R2为0 901。文章最后讨论了采用毒素处理棉苗子叶组织,建立黄萎病病指室内鉴定方法的可行性。

钙对黄瓜子叶愈伤组织中硝酸还原酶(NR)活性的影响

本文采用黄瓜子叶愈伤组织,研究了不同钙培养下,对愈伤组织生长、硝酸盐吸收,NR活性以及组织中钙、镁含量的影响。结果表明,缺钙后,愈伤组织生长、硝酸盐吸收、NR活性等都比正常钙培养下的愈伤组织降低。这与用整株植物所得结果基本一致,对此结果进行了讨论。

Determination of Emodin and Chrysophanol Contents in Callus of Cassia tora L. Leaf

[ Objective] Through inductive culture, emodin and chrysophanol contents in cassia seed were increased. [ Method ] MS culture medium was used to bourgeon seedlings of cassia seed and to induce cotyledon callus of cassia seed while HPLC method was adopted to determine emodin and ehrysophanol eontents.[ Result] Emedin and chrysophanol contents in cotyledon callus were 0. 099% and 0. 312%, respectively, while they were 0.029% and 0. 190% respectively in cassia seed. [ Conclusion] The method of inducing cotyledon callus was helpful for increasing emodin coment in cassia seed.

Histological Study on Soybean Somatic Embryogenesis

Soybean somatic cell could induce the development of embryoid which was similar to embryo morphologically and structurally. Somatic embryogenesis system of soybean was used to conduct genetic transformation of soybean because of its several advantages such as higher transformational efficiency, beetter synchronism and fewer plant chimeras among transgenic plants. After infected with agrobacterium tumefaciens,the initiation, differentiation and development of young cotyledon embryogenic cell of soybean which was cultured on selective culture medium with kanamycin were investigated through histological study. The result showed that somatic embryo was differentiated in non-bud differentiation way. The embryogenic cells were differentiated from epidermis of explant or cells in 1 layer or 2 layers, with the division of embryogenic cells and degradation and disorganization of surrounding cells, the embryogenic cells would form embryoid with analogous suspensor structure. Later, globular embryoid would extrude from epidermis then developed into heart-shape embryo. The experiment was expected to provide theoretical reference for the construction of high transformational system of using plant somatic embryogenesis induced by young cotyledon of soybean.

Preliminary Study on Tissue Culture Technique of Brassica campestris L. ssp. chinensis (L.) Makino var. utilis

In order to establish a rapid propagation system for Brassica campestris L. ssp. chinensis var. utilis, the anther and cotyledon-cotyledonary petioles were used as explants to conduct tissue culture research. The results showed that not bloomed flower buds with higher styles than petals were appropriate for anther cul- ture. Moreover, most microspores were at the mid-late uninucleate stage at that time. The pollen germination rates of Brassica campestris L. ssp. chinensis var. u- tills were low and the germination rates in autumn and winter were higher than that in summer. The induction medium of anther callus of Brassica campestris L. ssp. chinensis var. utilis was MS＋1.0 mg/L KT＋1.0 mg/L 2, 4-D＋3% sugar＋6 g/L agar＋ 8% coconut milk and the induction media of adventitious bud were MS＋2.0 mg/L 6-BA＋ 0.5 mg/L NAA＋I.0 g/L activated carbon＋2% sugar＋6 g/L agar or MS＋2.0 mg/L ZT＋ 0.5 mg/L IAA＋0.5 g/L AgNO3＋1.0 g/L activated carbon＋2% sugar＋6 g/L agar. The induction percentage of adventitious bud by anther culture was 36.7%. Browning phenomenon appeared during the culture of adventitious bud and regeneration plant could not be formed. The plant regeneration rate reached 80% when cotyledon- cotyledonary petioles were used as explant.

Structural Changes of Lignified Tissues from Sugarcane Leaves Induced by Smut （Sporisorium scitamineum） Virulence Factors

Sugarcane leaf shows the classical arrangement of cells, which defines a C4 species. Vascular bundles consist of xylem, phloem and fibres, surrounded by an outer layer ofsclereids and an inner ring of stone cells associated with the phloem. Some sclereids located below and above the vascular bundles act as docking cells and connect the vascular bundle to the internal surfaces of upper and lower layers of the epidermis. A compact mass ofsclereids occupies the total internal volume of the leaf edge. Neither docking cells nor the internal mass of sclereids in the edge were markedly coloured by phloroglucinol, indicating the absence of lignin in their cell walls. However, such staining indicated that fibres of the vascular bundle and the external layer of sclereids were strongly lignified. Incubation of leaf discs with an virulence factors produced by the pathogen Sporisorium scitamineum increased the thickness of the lignified cell walls of sclereids as well as the mid and small xylem vessels, as a possible mechanical defence response to the potential entry of the pathogen. This mechanism was mainly revealed for the resistant cv. Mayari 55-14, whereas lignification decreased for the susceptible cv. B 42231.

Induction and Characterization of Embryogenic Callus in Cotyledons Leaves of Tabebuia roseo-alba

Seeds from Tabebuia roseo-alba lose viability very fast. Moreover, the seed germination rate is very low, reaching approximately 40%. This study aimed at the in vitro induction of embryogenic callus. This technology allows subsequent plant regeneration as an alternative for the production of T. roseo-alba seedlings. Seeds were germinated in vitro and after 20 days, cotyledonary leaves, hypocotyls and root segments excised from these seedlings were used as explants. They were inoculated on MS medium supplemented with sucrose （30 g/L）, agar （5.0 g/L） and different auxins. The effect of 2,4-D, picloram and NAA at concentrations 0.0, 0.5, 1.0, 2.0 and 4.0 mg/L was evaluated. For the analysis of callus with embryogenic characteristics, ultra-structural study by scanning electron microscopy and cytochemical test with carmine were performed. The results showed that the culture medium supplemented with 4 mg/L NAA presented induction of callus with embryogenic characteristics in all explants used, with cotyledonary leaves showing the highest percentage （70% of explants with embryogenic characteristics）. The use of 2, 4-D and picloram was efficient for callus formation in different explants, but no embryogenic characteristics were observed. From the ultra-structural analysis of callus with embryogenic characteristics, it was found that cells from different explant sources had isodiametric format. This format is similar to somatic embryos in globular stage. The cytochemical analysis confirmed the presence of pro-embryogenic cells in callus mass. Callus induced from cotyledonary leaves presented 46% positive reaction to carmine acetic.

Preliminary Investigation on Somatic Embryogenesis from Immature Cotyledon Explants of Shea （Vitellaria paradoxa G,）

Long juvenile phase and lack of effective protocols for large scale vegetative propagation are limitations to domestication and improvement of the shea tree. The present study seeks to develop a protocol for plant regeneration of shea （Vitellaria paradoxa） from immature cotyledon explants. Embryogenic callus cultures were induced on Murashige and Skoog medium （MS） containing 3% sucrose, 0.24% Phytagel, and various concentrations of 2,4-Dichlorophenoxyacetic acid （2,4-D） after four weeks of culture in darkness. Rates of embryogenic callus induction were significantly affected by the addition of 2, 4-D to the medium. Within 28 days of culture, the highest percentage of embyogenic calli （77.61%） occurred on MS media containing 0.45 ~tM of 2,4-D in the dark. Somatic embryos were obtained by culturing embryogenic callus （in the dark） on MS medium fortified with 3% sucrose, 0.24% phytagel and devoid of growth regulators. Culturing at 16 h photoperiod restricted both the induction of embryogenic calli cultures and somatic embryos. Somatic embryos germinated, developed shoots and rooted vigorously on MS medium devoid of growth regulators. Germinated plantlets were acclimatized, successfully.