胡萝卜光自养型愈伤组织的诱导培养及其光合特性

经诱导得到胡萝卜光自养型愈伤组织。以叶绿素为单位计算,获得的光自养型愈伤组织的光合活力达到甚至超过了整体植株叶片水平。同时测定愈伤组织光自养过程中光合特性的变化,结果表明其叶绿素含量逐渐上升、暗呼吸速率和Chl a/Chl b比值逐渐下降。并且用电子显微镜观察到愈伤组织中叶绿体结构逐渐发育的过程。     

2,4—D对野生稻未成熟胚离体培养的影响及其其再生植株的田间表现（简报）

２,４－Ｄ浓度的高低同时影响野生稻未成熟胚愈伤组织的诱导率和其内在质量。２－８ｍｇ／Ｌ２,４－Ｄ适于稻种中未成熟胚Ｈ型与Ｋ型愈伤组织的形成,并能最大程度地减少Ｓ型愈伤组织的发生。Ｈ型愈伤组织再生个体的性状变异较Ｋ型的大,且与种子植株有显著差异。     

石刁柏愈伤组织形态发生能力及器官发生的研究

石刁柏愈伤组织可分为4种类型。淡绿色、紧实、块状的愈伤组织(A)为典型的器官发生型愈伤组织,根和芽分化率高;绿白色、紧实、瘤状的愈伤组织(B)形态发生能力低;淡黄色、松散、颗粒状的愈伤组织(C)为典型的胚胎发生型愈伤组织,胚状体分化率高;而黄褐色、较松散、团块状的愈伤组织(D)无形态发生能力。器官原基起源于愈伤组织中具单极性的分生细胞团。芽的发生多为外起源,亦有内起源;根的发生多为内起源,亦有外起源。     

柚木无性系愈伤组织诱导及植株再生

以柚木优良无性系71-14组培苗节间茎段为材料,MS 为基本培养基,采用正交设计对6-BA、IBA、TDZ、NAA 等4个生长调节剂各4水平进行愈伤组织诱导,并以最佳组合使用不同浓度的 TDZ 进行柚木愈伤组织再生.结果表明：TDZ 对形成具再生能力的致密型愈伤组织影响最大,低浓度水平的 TDZ 和6-BA 更易形成致密型愈伤组织;以愈伤组织大小、诱导率和致密型所占比例采用隶属函数法评定得出最优的愈伤组织诱导培养基为 MS＋0．9 mg·L-16-BA＋0．04 mg·L-1 IBA＋0．02 mg·L-1 TDZ＋0．8 mg·L-1 NAA,愈伤组织诱导率达80．78％、平均直径1．65 cm,获致密型愈伤组织83．0％;得出优化的再生培养基为 MS＋0．132 mg·L-1 TDZ,分化率为34．22％;初步建立了以茎段为外植体的柚木优良无性系71-14的再生体系,为柚木转基因技术的研究提供技术支撑.     

安祖花组织培养及其细胞和叶绿体发育过程的电镜观察

取安祖花的幼嫩叶片在添加适当浓度植物激素的ＭＳ培养基上,诱导愈伤组织并发化出试管苗,分别取疏松型和致密型的愈伤组织以及小苗幼嫩叶片进行电镜观察。结果显示,三者在细胞超微结构上有很显著的差异;疏松型愈伤组织的细胞细胞质稀薄,液泡大,细胞器的个烽少,观察不到典型的质体或前质体;而致密型愈伤组织细胞和幼嫩叶的细胞,细胞质浓,液泡小,并可清楚地观察到叶绿体和线粒体的内部结构及其发育过程。由此可以推断,经长     

安祖花组织培养及其细胞和叶绿体发育过程的电镜观察

取安祖花的幼嫩叶片在添加适当浓度植物激素的MS培养基上,诱导愈伤组织并分化出试管苗。分别取疏松型和致密型的愈伤组织以及小苗幼嫩叶片进行电镜观察。结果显示,三者在细胞超微结构上有很显著的差异：疏松型愈伤组织的细胞细胞质稀薄,液泡大,细胞器的个数少,观察不到典型的质体或前质体;而致密型愈伤组织细胞和幼嫩叶的细胞,细胞质浓,液泡小,并可清楚地观察到叶绿体和线粒体的内部结构及其发育过程。由此可以推断,经长期培养的愈伤组织细胞不能分化的原因之一是由于叶绿体过度退化,丧失其再生功能所造成的。     

影响谷子原生质体看护培养的一些因素

研究了谷子原生质体看护培养中一些问题。结果表明：不同种植物愈伤组织做看护细胞对谷子原生质体培养植板率有不同的影响。用光头稗草愈伤组织对谷子胚性、非胚性或中间型愈伤组织的原生质体进行看护培养,以对胚性愈伤组织原生质体的效果最好。看护培养主要是作用于原生质体形成完整细胞后的生长发育,试验没有观察到明显的看护细胞数量效应。     

早熟棉体细胞胚胎发生和植株再生体系的建立

以8个早熟或特早熟棉花为材料,通过不同激素组合(1.0 mg/L IBA+0.5 mg/L KT;0.1 mg/L 2,4-D+0.1 mg/L KT)诱导其愈伤组织,为早熟棉花的遗传转化以及基因功能研究奠定基础.结果表明,2种激素组合均能诱导产生4种主要类型的愈伤组织:淡黄色颗粒状愈伤组织,褐化的愈伤组织,翠绿致密的愈伤组织,疯长型愈伤组织.4种愈伤组织转入增殖培养基中前2种愈伤组织能够分化出胚性愈伤组织,胚性愈伤组织再转到分化培养基上培养能够产生胚状体,即体细胞胚;体细胞胚进一步发育成为再生小苗.用该组织培养再生系统,成功地使晋棉5号、中棉27号和辽棉10号等3个早熟棉品种在5～7个月内通过体细胞胚胎分化获得再生小苗.     

集胞藻Synechocystissp.PCC6803利用葡萄糖生长与光合能量转化的关系

用PAM叶绿素荧光仪测定了饥饿细胞、光自养细胞和混合营养细胞的叶绿素荧光 ,并对 3种类型细胞的荧光参数 :PSⅡ实际光化学效率 φⅡ和还原型质醌Q-A 进行了比较。用双重转盘磷光机测定了光自养细胞和混合营养细胞的毫秒延迟发光。根据叶绿素荧光动力学分析和毫秒延迟发光的结果及光合电子传递抑制剂 3,4_二氯苯基二甲脲 (DCMU)、二溴百里香醌 (DBMIB)对集胞藻 6 80 3(Synechocystissp .PCC 6 80 3)混合营养生长影响进行了分析 ,集胞藻 6 80 3混合营养培养的生长速率显著高于光自养培养的原因可能在于一是外源葡萄糖没有抑制反而是促进了混合营养细胞的光自养生长 ,二是呼吸基质向质醌库提供电子 ,使光合机构的能量转化加强 ,从而促进了集胞藻6 80 3细胞的利用葡萄糖的合成代谢。     

从棒头草(Polypogon fugax Nees ex Steud)幼穗培养获得体细胞胚和再生植株

棒头草幼穗在含2,4-D的MS培养基上诱导出了胚性、非胚性和中间型愈伤组织。根据形态、淀粉粒等指标可将组成这些愈伤组织的细胞分为三类。改变培养基中2,4-D的浓度,能诱导三类愈伤组织相互转变。从胚性愈伤组织中诱导形成了大量体细胞胚;体细胞胚是从单个原胚细胞直接发育而来,它们能正常萌发、再生小植株。这种再生能力现已保持了34个月。小植株移植在土壤中可以正常生长、分蘖、开花和结实。     

Photosynthesis and photoprotection in Nicotiana tabacum L. in vitro-grown plantlets

Nicotiana tabacum L. plantlets were cultured in vitro photoautotrophically (0% sucrose) and photomixotrophically (3% or 5% sucrose) at two irradiances (80 or 380 mumol m-2 s-1) with the aim of investigating the effect of these culture conditions on photosynthetic parameters and on protective systems against excess excitation energy. In plantlets grown photoautotrophically under higher irradiance photoinhibition was demonstrated. These plantlets had a decreased chlorophyll (Chl) a + b content and Chl a/b ratio, an increased content of xanthrophyll cycle pigments and a higher deepoxidation state, a decreased maximum photochemical efficiency of photosystem II (PS II) and actual photochemical efficiency of PS II, and an increased non-photochemical quenching. In the photoautotrophically grown plantlets and those photomixotrophically grown with 3% sucrose, the increase of growth irradiance from 80 to 380 mumol m-2 s-1 stimulated the activities of ascorbate-glutathione cycle enzymes with the exception of ascorbate peroxidase. Ascorbate peroxidase activity was not affected by the increase in growth irradiance but a significant decrease with increasing sucrose concentration was evident. The higher concentration of sucrose in the medium (5%) in combination with the higher irradiance inhibited photosynthesis (decrease in Chl a + b content and net photosynthetic rate) but no significant changes in activities of ascorbate-glutathione cycle enzymes were found. These results suggest that exogenous sucrose added to the medium improved high irradiance and oxidative stress resistance of the plantlets but the effect of sucrose is concentration dependent.     

Promoting root induction and growth of in vitro macadamia (<Emphasis Type="Italic">Macadamia tetraphylla</Emphasis> L. ‘Keaau’) plantlets using CO<Subscript>2</Subscript>-enriched photoautotrophic conditions

In this study, a rooting protocol was developed for macadamia plantlets with healthy roots and enhanced growth performance, along with enhanced photosynthetic capability. In vitro-grown shoots rooted in vented vessels containing vermiculite as the supporting material exhibited 100% frequency of root induction, whereas when shoots were grown in non-vented vessels containing a solidified Murashige and Skoog (MS) medium, the frequency of root induction was less than 30%. The formation of root with callus, hyperhydricity, and leaf necrosis was observed in this photomixotrophic closed system. The modification of the vented photoautotrophic system with different concentrations of CO₂ and sucrose were investigated using vermiculite as the supporter. The number of roots, root length, root surface area, fresh weight, and dry weight were significantly higher in plantlets grown in CO₂-enriched (1,000 μmol CO₂ mol⁻¹) photoautotrophic conditions. The water content in both root and shoot tissues of plantlets cultured under photoautotrophic conditions was maximized. In addition, shoot and leaf performances were enhanced in plantlets cultured under CO₂-enriched photoautotrophic conditions. The supplementation of sucrose (29–88 mM) to culture media in both ambient and elevated CO₂ conditions affected a reduction in the shoot and root performance of in vitro plantlets. Chlorophyll a, chlorophyll b, and total carotenoids in the leaf tissues of plantlets acclimatized in CO₂-enriched photoautotrophic conditions were enriched, leading to increasing photosynthetic abilities, including chlorophyll fluorescence and net photosynthetic rate. From this investigation, a root induction protocol was established and the production of healthy macadamia plantlets was successfully implemented using CO₂-enriched photoautotrophic conditions.     

Photoautotrophic potato cells: Transition from heterotrophic to autotrophic growth

Cells of potato (Solanum tuberosum L.) were obtained which were capable of photoautotrophic growth in liquid suspension culture under a photon flux density of 90–110 μmol m^?2 s^?1 PAR and in an atmosphere enriched with 2% CO₂. These photoautotrophic cells contained between 100 to 200 μg Chl (g fresh weight)^?1 and fixed CO₂ at a maximum rate of 16 μmol CO₂ (g fresh weight)^?1h^?1. In order to obtain cells capable of photoautotrophic growth it was necessary to adapt highly chlorophyllous heterotrophic cells (>50 μg Chl (g fresh weight)^?1) for growth in medium with 2.5 g sucrose 1^?1 (photomixotrophic cells). The photomixotropic cells had a Chl content of ca 100 μg Chl (g fresh weight)^?1 and were capable of photosynthetic activity which allowed them to survive after sugars had been depleted from the medium. It was from the photomixotrophic cells that cells capable of photoautotrophic growth were obtained. Heterotrophic cells initially established in liquid medium with 25 g sucrose I^?1 from chlorophyllous callus contained about 50 to 150 μg Chl (g fresh weight)^?1. However, after 5 to 10 passages the Chl content decreased to a maximum of 15 μg Chl (g fresh weight)^?1. These cells could not be adapted to photomixotrophic or photoautotrophic growth. These cells also were not able to regain Chl or initiate high rates of CO₂ fixation during the stationary phase of growth as did photomixotrophic cells or chlorophyllous heterotrophic cells. The loss of Chl exhibited by the cells during adaption to heterotrophic growth could be attributed at least in part to unbalanced growth (when cell division and growth exceeds Chl accumulation). Sucrose appeared to have an inhibitory effect directly on photosynthesis independent of Chl accumulation.     

Improved growth and acclimatization of somatic embryo-derived Oplopanax elatus plantlets by ventilated photoautotrophic culture

To improve large-scale in vitro production of Oplopanax elatus Nakai, we cultured somatic embryo-derived plantlets under a heterotrophic condition (semi-solid culture with sucrose), photoautotrophic condition (semi-solid culture without sucrose), or modified photoautotrophic condition (liquid culture with forced ventilation). The plantlets grown under the modified photoautotrophic condition had more leaves as well as higher chlorophyll content, and higher net photosynthetic rate than those grown under the conventional conditions. Further, the photoautotrophically grown plantlets acclimatized better and sooner upon ex vitro transplantation than did the conventionally cultured plantlets. Consequently, a photoautotrophic culture method with forced ventilation is effective for enhancing the growth and acclimatization of O. elatus.     

Developmental and Photosynthetic Characteristics of a Photoautotrophic Chrysanthemum Culture

Chrysanthemum plantlets were cultivated in vitro on media with 2.0, 0.3, or 0 % sucrose, or photoautotrophically without an organic carbon source but with supplementation of the culture vessel atmosphere with 2 % CO₂. The photoautotrophically cultivated plantlets showed a better growth and multiplication, higher contents of chlorophyll (Chl) and carotenoids, higher Chl a/b ratio, net photosynthetic rate and ribulose-1,5-bisphosphate carboxylase/oxygenase and phosphoenolpyruvate carboxylase activities than plantlets grown on the medium with sucrose. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of salinity on photosynthetic characteristics in photomixotrophic cell-suspension cultures from Alternanthera philoxeroides

We studied the effect of NaCl salinity on the development of cellular photosynthesis using a green, photomixotrophic, cell-suspension culture of Alternanthera philoxeroides (Mart.) Griseb. For these cells, increasing the concentration of sucrose in the media produces a rapid drop in net photosynthetic rate, which recovers as sucrose is depleted from the media. This predictable recovery provides a simple system to examine cellular photosynthetic development. Cells, unadapted to high salinity, were transferred to nutrient media with 30 mM sucrose (Control) or nutrient media with 30 mM sucrose and 100 mM NaCl (Salt). A dramatic increase in the dark respiration rate of Control and Salt cells during the first 6 d of the experiment produced net oxygen consumption in the light. The high dark respiration rates during this period were accompanied by a decline in total Chl and the amounts of two photosynthetic proteins, the light harvesting Chl a/b binding protein of photosystem II (LHCP) and the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco SSU). The dark respiration rate of Salt cells was greater than that of Control cells on days 4–8. After day 4, dark respiration rates decreased and net photosynthesis increased to stable values in both treatments at day 11 after media sucrose concentration reached a minimum. As dark respiration rates decreased and net photosynthetic rates increased, total Chl and the amounts of LHCP and rubisco SSU increased in both Control and Salt cells. The slower development of photosynthetic capacity in salt cells was correlated with a fresh weight that was 20% lower than that of control cells at the end of the experiment.     

Culture on sugar medium enhances photosynthetic capacity and high light resistance of plantlets grown in vitro

The significance of photosynthetic photon flux (PPF) and sugar feeding for the production of plants in vitro is only poorly understood. Nicotiana tabacum L. plantlets were grown photoautotrophically and photomixotrophically (3% sucrose) at two different PPFs (60 µmol m⁻² s⁻¹ and 200 µmol m⁻² s⁻¹) to investigate the effect of these culture parameters on photosynthetic performance and growth. Photomixotrophically‐grown plantlets showed an increase in carbohydrate content, mainly in glucose and fructose. Plant growth, dry matter accumulation and total leaf area were higher under photomixotrophic than photoautotrophic conditions. Not only biomass formation but also photosynthesis was positively affected by exogenous sucrose; the chlorophyll (Chl) content and the light‐saturated rate of photosynthetic oxygen evolution were higher in photomixotrophic plantlets. Photoinhibition occurred in plantlets that were grown photoautotrophically at the higher PPF. It became apparent as a loss in Chl content and photochemical efficiency. Photoinhibited plantlets showed a decrease in the D2/LHCII and CP47/LHCII ratios, suggesting a preferential loss of proteins from the photosystem II (PSII) core. The increased content of xanthophyll cycle pigments in photoinhibited plantlets indicated that also protective mechanisms were activated. Photomixotrophic growth of the plantlets prevented the occurrence of photoinhibitory symptoms. Therefore, we conclude that culture on sugar medium increases not only the photosynthetic potential but also the high light resistance of plantlets grown in vitro.     

Establishment and physiological analyses of photoautotrophic callus cultures of the fern Platycerium coronarium (Koenig) Desv. under CO2 enrichmen

Gametophyte-derived callus cultures of Platycerium coronariumcould be maintained under photoautotrophic conditions on Murashigeand Skoog medium supplemented with 2µM 2,4-dichlorophenoxyaceticacid (2,4-D) and with CO₂ enrichment. Progressive reductionof sucrose from the medium resulted in a reduction in growth,but an increase in total chlorophyll content. When subculturingwas delayed beyond 2 weeks, callus cells differentiated intogametophytes on the medium with 0.2 sucrose and no CO₂ enrichment.Enriching the photoautotrophic cultures on 2µM 2, 4-Dwith 1% CO₂ resulted in about 1.7-fold increase in fresh weightwithin 42 d. Total chlorophyll content was generally higherwith 1% CO₂ enrichment than with 10%. F_v/F_m ratio was higherfor callus on low levels of sucrose (>0.5%) than that onsucrose 1.0%. An increase in autofluorescence of chloroplasts,but not the size, was observed with decreasing sucrose levelsin the medium. Autofluorescence decreased with increase in CO₂from 0.03%. Our data are in agreement with the view that long-termexposure to high levels of decrease in photosynthetic capacity. Key words: Platycerium coronarium, stag's horn fern, autofluorescence of chloroplasts, confocal laser scanning microscope, F_v/F_m ratio, photoautotrophic callus     

A comparative study on growth and morphology of wasabi plantlets under the influence of the micro-environment in shoot and root zones during photoautotrophic and photomixotrophic micropropagation

The growth of wasabi (Wasabia japonica Matsumura) plantlets under different micro-environments inside culture vessels in photoautotrophic micropropagation (PA) and photomixotrophic micropropagation (PM) conditions were compared. After 28 days of culture, dry weight, relative growth rate, leaf area, and leaf chlorophyll contents of plantlets in PA were greater than those in PM. The number of leaves did not differ significantly between PA and PM conditions. PA promoted root growth and development with a greater number of roots, root length, root diameter, root fresh weight, root dry weight, and root xylem vessel system. Dissolved oxygen concentration in PA culture medium sharply decreased after 7 days of culture and then recovered. In PM culture medium, no significant fluctuation of dissolved oxygen concentration was apparent. The net photosynthetic rates of plantlets in PA were much higher than those in PM and increased with culture time. In contrast, the net photosynthetic rates of wasabi plantlets in PM kept a low and constant value during the culture period. With the presence of gas exchange membranes attached to the vessel lids, the detected vapor pressure deficit was higher in PA than in PM conditions. Higher stomatal density and larger stomatal aperture on the abaxial and adaxial surfaces of the leaves in PM medium promoted leaf water loss following ex vitro conditions. Thus, PA is applicable for producing healthy wasabi transplants.