Effect of ABA and sucrose on germination of encapsulated somatic embryos of guava (Psidium guajava L.)

Present study demonstrates the effect of sucrose and ABA on germination of encapsulated somatic embryos of guava (Psidium guajava L.). Sucrose and ABA at different concentrations were also evaluated for their effects on maturation and germination of somatic embryos. Mature somatic embryos developed on MS medium containing high concentration of sucrose (10%) or ABA (1.0 mg l⁻¹) showed inhibition in germination if they continued to be in same medium for 4 weeks. With increasing concentrations of sucrose (3–9%) or ABA (0.01–1.0 mg l⁻¹) in medium, percent germination of encapsulated somatic embryos decreased significantly. Encapsulated somatic embryos after storage on MS medium supplemented with 9% sucrose or 1 mg l⁻¹ ABA for different duration (0–60 days) germinated when they were transferred to medium containing 3% sucrose. About 20.8% and 37.5% encapsulated somatic embryos germinated after storage on ABA (1 mg l⁻¹) or sucrose (9%) for 60 days, respectively. Temporarily suppression in germination of encapsulated somatic embryos by high concentration of sucrose or ABA may be important for short-term conservation of elite genotype of guava.     

Studies on some physico-chemical changes associated with fruit ripening in tomato (Lycopersicon esculentum mill.)

The fruits of two tomato varieties were analysed at five stages of maturity, viz. mature green, turning, pink, red and red ripe, for some physico-chemical changes associated with fruit ripening. Fruit weight and size, pericarp thickness, drymatter, ascorbic acid, sugars, protein, N, P, Zn, Fe, Mn and Cu contents were observed to increase with maturity and reached maximum or near maximum at red stage. The acidity was maximum at turning or pink stage and then decreased to a minimum level at red ripe stage. Varietal differences were present.     

Responses of maize × teosinte derived backcross inbred lines (BILs) to maydis leaf blight (MLB) disease

Euphytica - Rice growth and productivity are greatly affected by cold stress, which is likely to become more of a hindrance for high and stable rice yields. To identify cold tolerance at the...     

Human dioxin-inducible cytochrome P1-450: complementary DNA and amino acid sequence

Induction of cytochrome P1-450 has been linked to susceptibility to certain chemically induced cancers in mouse and man. Treatment of the human cell line MCF-7 with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) results in high levels of aryl hydrocarbon (benzo[a]pyrene) hydroxylase (P1-450) activity. This cell line was used to isolate a human P1-450 full-length complementary DNA (cDNA) clone. The cDNA is 2566 nucleotides in length, encodes a polyadenylated messenger RNA (2.8 kilobases in length), and has a continuous reading frame producing a protein with 512 residues (molecular weight, 58,151). The human P1-450 cDNA and protein are 63 percent and 80 percent similar to mouse P1-450 cDNA and protein, respectively. Whereas the mouse TCDD-inducible P-450 gene subfamily has two members (P1-450 and P3-450), the human TCDD-inducible gene subfamily appears to have only one gene (P1-450).     

Guar genes to genome and meta-analysis of SSR markers in sequencing studies

Genetic Resources and Crop Evolution - Guar (Cyamopsis tetragonoloba (L.) Taub.), or cluster bean, traditionally grown for vegetable and fodder, has gained commercial importance across the globe...     

Elemental accumulation in mango (Mangifera indica L.) as a function of maturity stage and variety

Information about the nutritional status of a plant is a basic prerequisite for its adequate nutrition and is crucial to achieve high-yield productivity. Assessing the annual amount of nutrient that a tree needs to absorb in order to successfully complete a vegetative and reproductive growth is a fundamental step for developing rational fertilization in orchards. We are unaware of any report describing macro- and micronutrient dynamics in fruit at different growth stages of mango. Seven cultivars of mango (Dashehari, Langra, Mahmood Bahar, Menka, Sabri, Sundar Langra and Zardalu) were selected for the study. Different macronutrients such as nitrogen, phosphorus, potassium, calcium and magnesium (N,P, K, Ca, and Mg) and micronutrients such as iron, manganese, zinc and copper (Fe, Mn, Zn, and Cu) were analyzed at four growth stages, namelymarble stage, prestone formation stage, stone hardening stage and harvest stage. There was a significant variation in nutrient content of fruits throughout the developmental stages irrespective of cultivars. There was no definite trend of nutrient variation among cultivars but in general, most of the nutrients like N, P, K, Mg, Mn, Zn, and Cu were the highest at the marble stage, and Ca and Fe at the stone hardening stage.     

Barley grain constituents, starch composition, and structure affect starch in vitro enzymatic hydrolysis

The relationship between starch physical properties and enzymatic hydrolysis was determined using ten different hulless barley genotypes with variable carbohydrate composition. The ten barley genotypes included one normal starch (CDC McGwire), three increased amylose starches (SH99250, SH99073, and SB94893), and six waxy starches (CDC Alamo, CDC Fibar, CDC Candle, Waxy Betzes, CDC Rattan, and SB94912). Total starch concentration positively influenced thousand grain weight (TGW) (r(2) = 0.70, p < 0.05). Increase in grain protein concentration was not only related to total starch concentration (r(2) = -0.80, p < 0.01) but also affected enzymatic hydrolysis of pure starch (r(2) = -0.67, p < 0.01). However, an increase in amylopectin unit chain length between DP 12-18 (F-II) was detrimental to starch concentration (r(2) = 0.46, p < 0.01). Amylose concentration influenced granule size distribution with increased amylose genotypes showing highly reduced volume percentage of very small C-granules (<5 μm diameter) and significantly increased (r(2) = 0.83, p < 0.01) medium sized B granules (5-15 μm diameter). Amylose affected smaller (F-I) and larger (F-III) amylopectin chains in opposite ways. Increased amylose concentration positively influenced the F-III (DP 19-36) fraction of longer DP amylopectin chains (DP 19-36) which was associated with resistant starch (RS) in meal and pure starch samples. The rate of starch hydrolysis was high in pure starch samples as compared to meal samples. Enzymatic hydrolysis rate both in meal and pure starch samples followed the order waxy > normal > increased amylose. Rapidly digestible starch (RDS) increased with a decrease in amylose concentration. Atomic force microscopy (AFM) analysis revealed a higher polydispersity index of amylose in CDC McGwire and increased amylose genotypes which could contribute to their reduced enzymatic hydrolysis, compared to waxy starch genotypes. Increased β-glucan and dietary fiber concentration also reduced the enzymatic hydrolysis of meal samples. An average linkage cluster analysis dendrogram revealed that variation in amylose concentration significantly (p < 0.01) influenced resistant starch concentration in meal and pure starch samples. RS is also associated with B-type granules (5-15 μm) and the amylopectin F-III (19-36 DP) fraction. In conclusion, the results suggest that barley genotype SH99250 with less decrease in grain weight in comparison to that of other increased amylose genotypes (SH99073 and SH94893) could be a promising genotype to develop cultivars with increased amylose grain starch without compromising grain weight and yield.