The dynamics of nutrient utilization and growth of apple root stock ‘M9 EMLA’ in temporary versus continuous immersion bioreactors

The present study investigated the dynamics of nutrient utilization and various growth and physiological parameters during in vitro proliferation of apple root stock ‘M9 EMLA’ in two different bioreactor systems, i.e. temporary and continuous immersions. Individual shoots obtained from temporary immersion system had higher dry mass and were of better quality than those obtained from continuous immersion. In continuous immersion bioreactor, apple shoots appeared to utilize more nutrients from liquid culture medium than that from temporary immersion. The shoot growth was limited by the availability of phosphate and nitrogen in continuous immersion system. The shoots produced in temporary immersion bioreactor showed higher photosynthetic rate, maximum quantum yield of photosystem-II and slow but steady rate of nutrient absorption, indicating the occurrence of higher photomixotrophic metabolism. The study also showed that high level of antioxidant scavenging enzymes in shoots grown in continuous immersion system induced physiological changes to foster adaptation to stresses.     

Fitness of resprouters versus seeders in relation to nutrient availability in two Plantago species

Two contrasting strategies of plants from disturbed areas are reported to depend on nutrient availability. Resprouters, investing into storage and capable of vegetative regeneration after disturbance, are predicted to be enhanced in nutrient poor environments. This contrasts to seeders, which invest preferentially into seed production and regenerating only from seeds, and are thought to prevail in nutrient rich environments. To test such predicted dichotomy, we set up an experiment with two facultative resprouters with contrasting nutrient demands and assessed the fitness of individuals regenerated from seeds and root fragments in differently productive environments. We hypothesized that 1) plants with higher nutrient demands have a higher fitness as seeders irrespectable of nutrient availability and/or 2) both species will have a higher fitness as resprouters under lower nutrient availability and as seeders when nutrient availability is higher. Nutrient availability was also manipulated prior to and after disturbance to evaluate the impact of changing nutrient availability on the strategy of resprouting. The results of our pot experiment with Plantago lanceolata and Plantago media supported the first but not the second hypothesis. Moreover, high nutrient availability prior to disturbance negatively affected resprouting success, but the growth and fitness of successfully regenerated individuals were enhanced under higher nutrient availability. We concluded that resprouting from roots after disturbance is affected by nutrient availability, but this effect considerably differs between individual life-history stages.     

Kinetics of ammonium, nitrate and phosphorus uptake by Canna indica and Schoenoplectus validus

Canna indica L. is an upright perennial rhizomatous herb, and Schoenoplectus validus (Vahl) A. Löve and D. Löve is a tall, perennial, herbaceous sedge. The nutrient uptake kinetics of C. indica and S. validus were investigated using the modified depletion method after plants were grown for 4 weeks in simulated secondary-treated wastewater. The maximum uptake rate (I_max) and Michaelis–Menten constant (K_m) were estimated by iterative curve fitting. The I_max for NH₄N (623 μmol g⁻¹ dry root weight h⁻¹) was significantly higher than that for NO₃N (338 μmol g⁻¹ dry root weight h⁻¹) in S. validus. In contrast, no difference was observed in C. indica. The I_max values for NO₃N and NH₄N were higher in S. validus than in C. indica. A significantly lower K_m was detected for NO₃N uptake in C. indica (385 μmol L⁻¹) compared to that in S. validus (1908 μmol L⁻¹). The I_max for PO₄P did not differ between the plant species. The K_m for PO₄P was significantly higher in C. indica (157 μmol L⁻¹) than in S. validus (60 μmol L⁻¹). In conclusion, we found that S. validus preferred NH₄N over NO₃N, had greater capacity for N uptake and higher affinity for PO₄P, but C. indica had greater affinity for NO₃N. Nutrient uptake capacity is likely related to habitat preference, and is influenced by the structure of roots and rhizomes.     

In vivo measurement of shoulder joint loads during activities of daily living

Until recently the contact loads acting in the glenohumeral joint have been calculated using musculoskeletal models or measured in vitro. Now, contact forces and moments are measured in vivo using telemeterized shoulder implants. Mean total contact forces from four patients during eight activities of daily living are reported here.Lifting a coffee pot (1.5 kg) with straight arm caused an average force of 105.0%BW (%body weight) (range: 90–124.6%BW), while setting down the coffee pot in the same position led to higher forces of 122.9%BW on the average (105.3–153.4%BW). The highest joint contact forces were measured when the straight arm was abducted or elevated by 90° or more, with a weight in the hand. Lifting up 2 kg from a board up to head height caused a contact force of 98.3%BW (93–103.6%BW); again, setting it down on the board led to higher forces of 131.5%BW (118.8–144.1%BW). In contrast to previously calculated high loads, the contact force during passive holding of a 10 kg weight laterally was only 12.3%BW (9.2–17.9%BW), but when lifting it up to belt height it increased to 91.5%BW (87–95%BW).The moments transferred inside the joint at our patients varied much more than did the forces both inter and intra-individually.Our data suggest that patients with shoulder problems or during the first post-operative weeks after shoulder fractures or joint replacements should avoid certain activities encountered during daily living e.g. lifting or holding a weight with an outstretched arm. Some energy-related optimization criteria used in the literature for analytical musculoskeletal shoulder models must now be reconsidered.     

Parasitism of an insect Manduca sexta L. alters feeding behaviour and nutrient utilization to influence developmental success of a parasitoid

The effects of macronutrient balance on nutrient intake and utilization were examined in Manduca sexta larvae parasitized by Cotesia congregata. Insects fed an artificial diet having constant total macronutrient, but with varied ratios of protein and carbohydrate, with altered diet consumption in response to excesses and deficiencies of the individual macronutrients. Bivariate plots of protein and carbohydrate consumption for non-parasitized larvae demonstrated a curvilinear relationship between points of nutrient intake for the various diets, and the larvae grew best on carbohydrate-biased diets. The relationship was linear for parasitized larvae with the growth uniform across diets. On protein-biased diets, the larvae regulated the nitrogen content, containing similar amounts of nitrogen regardless of consumption. Efficiency of nitrogen conversion in non-parasitized larvae was greatest on carbohydrate-biased diets, while nitrogen conversion by parasitized larvae was greatest with intermediate nutrient ratios. Accounting for carbohydrate consumption, the lipid content decreased as dietary carbohydrate increased, but parasitized larvae contained significantly less lipid. The total biomass of parasites developing in individual host larvae was positively correlated with host protein consumption, but the individual parasites were similar in size. Parasitism influences host nutrient consumption in a manner that achieves uniform host growth under diverse nutritional regimes, thereby constraining blood nutrient concentrations within limits suitable for parasite growth and development.     

Free and conjugated polyamines during de novo floral and vegetative bud formation in thin cell layers of tobacco

The concentrations of three classes of polyamines, trichloroacetic acid-soluble (free), TCA-soluble conjugated (to small molecules) and TCA-insoluble conjugated (to macromolecules), was examined during de novo floral and vegetative bud formation in thin cell layers of Nicotiana tabacum L. cv. Samsun. Explants (consisting of 5–6 layers of epidermal, subepidermal and parenchyma cells) were excised either from floral pedicels or from stem internodes at the unripe fruit stage and cultured on the same medium. In the former, the first de novo formed flower buds appeared on day 8 of culture, while in the latter the first vegetative domes appeared on day 10. In both cases the number of floral and vegetative buds increased up to day 12 and 15, respectively. Changes in dry weight were determined throughout the culture period. Free and conjugated putrescine titer increased 5–60 times in both types of culture and in the three classes of polyamines examined; spermidine content also increased, while spermine, when present, did not show significant changes. TCA-soluble conjugated polyamines were most abundant, being about 2-fold the TCA-insoluble conjugated ones and 10-fold the free ones. The major increment in putrescine and spermidine content occurred in stem internode explants developing vegetative buds. In pedicel explants the maximum putrescine level was reached before or on day 8 in culture (emergence of the first flower buds with calyx initials), while in stem internode explants the maximum level was reached on day 12, at the emergence of the first vegetative buds with leaf primordia. While spermidine prevailed on day 0, putrescine was the most abundant polyamine during both differentiation processes. The putrescine content rapidly increased immediately after the onset of culture. Thus conjugated polyamines, especially putrescine, and not only the free ones, seem to be involved in both the reproductive and vegetative phases of tobacco growth and development.     

5种杀虫剂对西花蓟马和花蓟马的毒力及其生理酶活性的影响

【目的】探究不同杀虫剂对重要入侵害虫西花蓟马及其本地近缘种花蓟马的毒力及对保护酶和解毒酶活性的影响,为进一步研究2种害虫的抗性管理提供依据。【方法】采用浸渍法测定5种田间常用杀虫剂对西花蓟马和花蓟马的毒力,并测定杀虫剂亚致死浓度(LC25)下2种蓟马体内保护酶和解毒酶活性的差异。【结果】不同杀虫剂对2种蓟马的毒力依次为:乙基多杀菌素甲维盐阿维菌素吡虫啉噻虫嗪,乙基多杀菌素对西花蓟马和花蓟马的LC_(50)分别为0.28和0.03 mg·L~(-1)。不同药剂的亚致死剂量(LC_(25))对西花蓟马和花蓟马体内保护酶和解毒酶活性普遍具有诱导作用。其中,阿维菌素对西花蓟马超氧化物歧化酶(SOD)活性诱导作用最强,为326.40 U·mg~(-1),是对照的9.37倍,而乙基多杀菌素对花蓟马SOD活性诱导作用最强,为245.35 U·mg~(-1),是对照的9.32倍;吡虫啉对西花蓟马和花蓟马过氧化物酶(POD)诱导作用最强,分别为298.67和246.79 U·mg~(-1),是对照的37.10和20.57倍;阿维菌素对西花蓟马和花蓟马过氧化氢酶(CAT)和羧酸酯酶(CarE)诱导作用最强,分别为298.67、246.79 U·mg~(-1)(CAT活性)和12.53、11.99 U·mg~(-1)(CarE活性);乙基多杀菌素对西花蓟马和花蓟马谷胱甘肽转移酶(GST)和乙酰胆碱酯酶(AChE)诱导作用最强,分别为77527.59、66927.39 U·mg~(-1)(GST活性)和2.34、2.22 U·mg~(-1)(AChE活性)。【结论】5种杀虫剂中,乙基多杀菌素对2种蓟马的毒力最强;西花蓟马对杀虫剂的解毒代谢能力强于花蓟马。     

新疆野杏开花物候与花器官对海拔的响应

新疆野杏(Prunus armeniaca Lam.)是天山野果林的优势种,具有重要的生态与资源价值。野果林的生境条件与其分布及生长密切相关。为了明确新疆野杏在不同海拔下的开花物候与花器官变化规律,于2021年3月—4月,选择新疆新源县吐尔根杏花沟野杏林为研究区,在野杏集中分布的1000—1500m的山地,由低到高划分Ⅰ—Ⅴ级海拔梯度设置样地,监测环境条件,对野杏群体开花物候期与花器官发育特征进行调查。结果表明：(1)新疆野杏群体开花物候期历时32d左右,各海拔梯度最长相差2d,第Ⅰ级与第Ⅱ级海拔的开花物候期差异不明显,其他海拔梯度间均存在显著差异,开花最晚的第Ⅴ级比最早的第Ⅰ级晚9d,但群体开花期长4d,海拔梯度与开花物候期呈显著正相关,而温度与开花物候期呈显著负相关;(2)新疆野杏的花萼长度和宽度、子房高度和宽度均是第Ⅱ级海拔的最大;花冠直径、花瓣纵径和横径均是第Ⅰ级的最大,花药长度和宽度均是第Ⅳ级的最大;花柱长度是第Ⅴ级的最大。海拔与花的外部器官、雌蕊呈显著负相关,与雄蕊呈显著正相关;光照强度与花的外部器官、雌蕊呈显著负相关;(3)新疆野杏开花期气候因子,第Ⅳ级、第Ⅴ级与第Ⅰ级存...     

桉树与红锥混交对土壤水解酶活性及其化学计量特征的影响

为从土壤酶活性及其化学计量特征的角度,揭示桉树与珍贵乡土树种混交后土壤养分的响应机制,该文以广西凭祥热林中心青山实验场的桉树纯林、红锥纯林和桉树×红锥混交林为研究对象,采用随机区组试验设计,通过测定土壤碳(C)、氮(N)、磷(P)水解酶[β-1,4-葡萄糖苷酶(BG)、β-1,4-N-乙酰葡糖氨糖苷酶(NAG)、亮氨酸氨基肽酶(LAP)和酸性磷酸酶(ACP)]的活性及土壤理化性质,分析桉树与红锥混交对土壤养分状况的影响。结果表明：(1)桉树与红锥混交在0～10 cm和10～20 cm土层均显著提高pH值、有效氮(AN)和有效磷(AP)的含量以及LAP酶活性,显著降低BG和ACP酶活性,但对NAG酶活性影响不显著。(2)SOC和TN与除酶C∶N外的其他土壤水解酶活性及其化学计量比呈现不同程度的显著正相关。(3)在0～10 cm和10～20 cm土层,三种林分间土壤水解酶活性均具有显著差异,SOC和AN含量是土壤水解酶活性产生差异的驱动因子。(4)桉树纯林、桉树×红锥混交林和红锥纯林在0～20 cm土层土壤酶C∶N∶P分别为1∶1.08∶1.37、1∶1.16∶1.34和1∶1.07∶1....     

The mechanism of sex-specific splicing at the doublesex gene is different between Drosophila melanogaster and Bombyx mori

We have previously reported that Bmdsx, a homologue of the sex-determining gene, doublesex (dsx), was found to be sex-specifically expressed in various tissues at larval, pupal, and adult stages in the silkworm, Bombyx mori, and was alternatively spliced to yield male- and female-specific mRNAs. To reveal sex-specific differences in splicing patterns of Bmdsx pre-mRNA, the genomic sequence was determined and compared with male- and female-specific Bmdsx cDNA sequences. The open reading frame (ORF) consisted of five exons. Exons 3 and 4 were specifically incorporated into the female type of Bmdsx mRNA. On the other hand, exon 2 was spliced to exon 5 to produce the male type mRNA of Bmdsx. As in the case of Drosophila dsx, the OD2 domain was separated by a female-specific intron into sex-independent and sex-dependent regions. Sex-specific splicing occurred in equivalent positions in the Drosophila dsx gene. However, unlike Drosophila dsx, the female-specific introns showed no weak 3′ splice sites, and the TRA/TRA-2 binding site related sequences were not found in the female-specific exon, nor even in any other regions of the Bmdsx gene. Moreover, an in vitro splicing reaction consisting of HeLa cell nuclear extracts showed that the female-type of Bmdsx mRNA represented the default splicing. These findings suggest that the structural features of the sex-specific splicing patterns of Bmdsx pre-mRNA are similar to those of Drosophila dsx but the regulation of sex-specific alternative splicing of Bmdsx pre-mRNA is different.     

Survival of Brevibacterium linens during nutrient starvation and intracellular changes

The present work reports the survival capacity of a strain of Brevibacterium linens isolated from a French camembert cheese and the ensuing changes in cell composition. Exponentially growing cells were harvested, washed and resuspended with shaking in pH 8.0 buffer at 21°C in the absence of a carbon source. The viability of this strain, assessed with slide cultures, is much less than that of coryneform bacteria isolated from soil samples, even though no cell lysis was detected. Intracellular RNA was rapidly consumed during the first few days although magnesium levels remained high. The quantity of DNA initially increased by 17% within 24 h and then remained stable during the 30 days of the experiment. During the same period, absorbance of the medium at 260 nm reached 2 absorbance units. Reserve polysaccharides in this strain are less abundant than in Arthrobacter and were rapidly consumed. Proteolysis was regular and thus maintained a pool of free amino acids which was greater than 60% of the initial value. There was a parallel accumulation of ammonia in the medium. Catalase activity decreased regularly during the first 80 h whereas the quantity of Adenosine-5-triphosphate (ATP) dropped by 47% in 10 h, stabilizing at less than 10% of its initial value. Cell respiration declined very rapidly and was very low after 24 h.     

Nitrogen utilization by the raphidophyte Heterosigma akashiwo: Growth and uptake kinetics in laboratory cultures

The nitrogen uptake and growth capabilities of the potentially harmful, raphidophycean flagellate Heterosigma akashiwo (Hada) Sournia were examined in unialgal batch cultures (strain CCMP 1912). Growth rates as a function of three nitrogen substrates (ammonium, nitrate and urea) were determined at saturating and sub-saturating photosynthetic photon flux densities (PPFDs). At saturating PPFD (110 μE m⁻² s⁻¹), the growth rate of H. akashiwo was slightly greater for cells grown on NH₄⁺ (0.89 d⁻¹) compared to cells grown on NO₃⁻ or urea, which had identical growth rates (0.82 d⁻¹). At sub-saturating PPFD (40 μE m⁻² s⁻¹), both urea- and NH₄⁺-grown cells grew faster than NO₃⁻-grown cells (0.61, 0.57 and 0.46 d⁻¹, respectively). The N uptake kinetic parameters were investigated using exponentially growing batch cultures of H. akashiwo and the ¹⁵N-tracer technique. Maximum specific uptake rates (V_max) for unialgal cultures grown at 15 °C and saturating PPFD (110 μE m⁻² s⁻¹) were 28.0, 18.0 and 2.89 × 10⁻³ h⁻¹ for NH₄⁺, NO₃⁻ and urea, respectively. The traditional measure of nutrient affinity—the half saturation constants (K_s) were similar for NH₄⁺ and NO₃⁻ (1.44 and 1.47 μg-at N L⁻¹), but substantially lower for urea (0.42 μg-at N L⁻¹). Whereas the α parameter (α = V_max/K_s), which is considered a more robust indicator for substrate affinity when substrate concentrations are low (<K_s), were 19.4, 12.2 and 6.88 × 10⁻³ h⁻¹/(μg-at N L⁻¹) for NH₄⁺, NO₃⁻ and urea, respectively. These laboratory results demonstrate that at both saturating and sub-saturating N concentrations, N uptake preference follows the order: NH₄⁺ > NO₃⁻ > urea, and suggests that natural blooms of H. akashiwo may be initiated or maintained by any of the three nitrogen substrates examined.     

Improvement of xylose utilization in Clostridium acetobutylicum via expression of the talA gene encoding transaldolase from Escherichia coli

Clostridium acetobutylicum ATCC 824 was metabolically engineered for improved xylose utilization. The gene talA, which encodes transaldolase from Escherichia coli K-12, was cloned and overexpressed in C. acetobutylicum ATCC 824. Compared with C. acetobutylicum ATCC 824 (824-WT), the transformant bearing the E. coli talA gene (824-TAL) showed improved ability on xylose utilization and solvents production using xylose as the sole carbon source. During the fermentation of xylose and glucose mixtures with three xylose/glucose ratios (approximately 1:2, 1:1 and 2:1), the rate of xylose consumption and final solvents titers of 824-TAL were all higher than those of 824-WT, despite glucose repression on xylose uptake still existing. These results suggest that the insufficiency of transaldolase in the pentose phosphate pathway (PPP) of C. acetobutylicum is one of the bottlenecks for xylose metabolism and therefore, overexpressing the gene encoding transaldolase is able to improve xylose utilization and solvent production.     

不同生境中鬼针草(Bidens pilosa)碳氮磷化学计量特征及其营养利用策略

该研究通过野外采样和实验室测定的方法,研究了三种生境中鬼针草叶和根碳(C)、氮(N)、磷(P)化学计量特征及其与土壤养分的相关性。结果表明:(1)鬼针草的生境具有不同的资源水平。三种生境的土壤全氮(TN)和速效氮贫乏,有机碳(C)和全磷(TP)较充裕;生境Ⅰ土壤TN含量显著低于其它两个生境,生境II土壤TP含量显著低于其它两个生境,生境III土壤TN、TP含量均大于其它两个生境。(2)不同生境的鬼针草对磷(P)分配策略不同。低N生境的鬼针草叶片P含量根P含量,P较多地分配到植物体地上部分;N、P含量较高的生境中鬼针草根P含量叶P含量,P更多地分配到地下部分。(3)不同生境的鬼针草其地上部分和根的生长速率不同。低N生境的鬼针草叶片N/P和C/P值小,植物体具有较高的相对生长速率,具有地上生长竞争优势;低P生境的植物叶片N/P和C/P值大,植物体具有较慢的相对生长速率;高N、高P生境中根N/P和C/P值小,根具有较高的生长速率,保证了鬼针草的地下生长竞争优势。(4)鬼针草叶片N/P和根N/P之间呈现不显著的负相关关系,植物地上部分和地下部分为异速生长。不同生境的鬼针草具有不同的营养利用和分配策略,保证了植物强大的竞争力和入侵性。     

七叶一枝花种子萌发过程中内源激素含量及酶活性变化研究

为探究七叶一枝花的种子萌发生理机制,该文从种胚形态上对七叶一枝花种子萌发过程的时期进行了划分,并分析了不同时期种子内源激素含量及相关酶活性的变化规律。结果表明:(1)根据种胚形态可将种子萌发过程细分为8个时期,即种胚未萌动时期(S1期)、心形胚时期(S2期)、种胚膨大时期(S3期)、胚根未突破种皮时期(S4期)、子叶柄伸长和胚根突破种皮时期(S5期)、下胚轴突破种皮时期(S6期)、上胚轴伸长时期(S7期)、胚根伸长时期(S8期)。(2)不同萌发时期种子的α-淀粉酶活性均明显高于β-淀粉酶。(3)超氧化物歧化酶(SOD)活性在S5期最高,S1期最低; 过氧化物酶(POD)和过氧化氢酶(CAT)活性随种子萌发进程总体呈上升趋势,可溶性蛋白含量随种子萌发进程先下降后升高。(4)吲哚乙酸(IAA)、赤霉素(GA₃)、脱落酸(ABA)和水杨酸(SA)含量随种子萌发进程整体呈下降趋势; 1-氨基环丙烷羧酸(ACC)、茉莉酸(JA)、油菜素内酯(BRs)随种子萌发进程整体呈上升趋势; 细胞分裂素类(CTKs)含量无显著变化; IAA/ABA和GA₃/ABA随种子萌发进程呈先下降后上升趋势,而CTKs/ABA则不断升高。(5)ABA、IAA、GA₃含量与胚率呈负相关,而ACC、JA、BRs、POD、CAT、β-淀粉酶活性与胚率呈正相关。综上认为,七叶一枝花在不同时期种子内源激素含量及相关酶活性各不相同,其中α-淀粉酶活性、POD活性可能与种胚胚根伸长有关,GA₃可能影响种胚形成,而ABA则可能抑制种胚的生长发育。     

Wavelength-specific photosynthetic responses of Halophila johnsonii from marine-influenced versus river-influenced habitats

The seagrass Halophila johnsonii Eiseman grows from the upper intertidal to 3 m depths in habitats ranging from near-marine inlets to tidal riverine. These habitats have distinct optical characteristics, primarily due to variable concentrations of watershed-derived chromophoric dissolved organic matter (CDOM), which increases the attenuation of short-wavelength (blue and UV) light. H. johnsonii contains a suite of flavonoids that are thought to serve as UV-protective pigments (UVP). In this study, photosynthetic responses at specific wavelengths were compared between plants from a river-influenced high-CDOM habitat (Oleta River) and those from an adjacent marine, low-CDOM environment (Haulover Inlet) in Florida. Oxygen flux was used to measure dark respiration and photosynthesis under near-constant radiant energy at nine specific wavelengths from 340 to 730 nm. Riverine plants had higher gross photosynthetic rates and quantum efficiencies than inlet plants at the shortest wavelengths (350, 400 and 450 nm), while inlet plant photosynthetic rates and quantum efficiencies were higher at the two longest wavelengths measured (694 and 730 nm). Riverine plants also exhibited greater variation in photosynthetic responses across the spectrum and more variable pigment levels among replicates. Chlorophyll a and b concentrations were significantly greater in riverine plants suggesting that they were more shade-acclimated compared to the marine populations. Differences in wavelength-specific photosynthetic responses and chlorophyll levels indicate that the riverine plants were blue-shade acclimated. The higher and more variable UVP levels in the riverine population were not consistent with shade acclimation; however, these flavonoid pigments may protect chloroplasts from photodamage during short-term, high intensity irradiance conditions that occur over the course of tidal cycles at this highly fluctuating riverine site.     

Plantlet differentiation in leaf and root cultures of birch (Betula Pendula roth.)

The newly-formed leaves on plantlets differentiated from shoot bud cultures of Betula pendula, when excised and grown on a fresh medium produced callus from the margins or regenerated leafy shoots, roots and plantlets. After 4 weeks, upon transfer to murashige and Skoog (MS) medium supplemented with 3-indoleacetic acid (IAA) + 6-(4-hydroxy-3-methyl-trans-2-enyl)aminopurine (zeatin) + 6-aminopurine (adenine), 15–20 plantlets were produced from each explant. Likewise, the roots also showed meristematic activity at several sites, and produced nodulated callus on MS + α-naphthaleneacetic acid (NAA) + 6-(3-methyl-2-butenyl-amino)purine (2-iP) + adenine, and ultimately differentiated plantlets. Anatomical studies showed that initiation of callus takes place by meristematic activity in epidermal cells of leaves, and cortical cells of roots. Cytological investigations revealed no change in chromosomal complement.     

Improved guggulsterone production from sugars, precursors, and morphactin in cell cultures of Commiphora wightii grown in shake flasks and a bioreactor

Cell cultures of Commiphora wightii (Arnott.) Bhandari were grown in shake flasks and a bioreactor and an increase in guggulsterone accumulation up to 18 μg l⁻¹ was recorded in cells grown in the production medium containing a combination of sucrose:glucose (4% total), precursors (phenylalanine, pyruvic acid, xylose, and sodium acetate), morphactin, and 2iP. A yield of 10 g l⁻¹ biomass and ∼200 μg l⁻¹ guggulsterone was recorded in a 3-l flask and in a 2-l stirred tank bioreactor compared with 6.6 g biomass and 67 μg l⁻¹ guggulsterone in 250-ml flasks. Increased vessel size was correlated with increased biomass and guggulsterone accumulation. 2iP alone was not effective for biomass and guggulsterone accumulation in cell cultures of C. wightii.