An alternative method of flax retting during dry weather

During exceptionally dry and hot weather undesiccated flax (Linum usitatissi-murri) and flax desiccated with glyphosate that was pulled and laid on the ground to dew-ret, retted 1–2 wk before flax that was desiccated and left as a standing crop. This was because dew-retted flax was colonised by fungi faster than that left standing. Cladosporium herbarum, Epicocum nigrum and yeast, including Aureoba-sidium pullulans, appeared first; they were followed by Alternaria alternata, Fusarium culmorum and Phoma, Mucor and Rhizopus species. The standing crop retted more slowly despite the presence of greater concentrations of cell-wall degrading enzymes. However, the fibres of flax retted as a standing crop retained more of their strength than those of flax retted on the ground. Thus dew-retting provides means of retting when the weather is dry and hot.     

Relationship between pectin content of stems of flax cultivars, fungal cell wall-degrading enzymes and pre-harvest retting

Of five flax cultivars suitable for fibre production Ariane retted most rapidly and Belinka and Hera were the slowest to ret after treatment with the herbicide glyphosate. Prematurely senescing stems of the different cultivars bore the same populations of saprophytic, filamentous fungi. More polygalacturonase (PG) activity was detected in retting, naturally-colonised stems of Belinka, Hera and Regina than in stems of Ariane or Natajsa but pectin-lyase (PL) activities were not significantly different. The pectic substance content of stem cell walls varied between cultivars; Hera and Belinka contained significantly the greatest amount, 34-0 and 32-5% w/w respectively and Ariane contained the least, 26-3% w/w. Significant differences in xylan content of cell walls were not obtained but the highest levels of xylanase activity were detected in colonised stem tissues of Belinka. Fibres of this cultivar were found to be slightly weaker than those of the other cultivars but also the finest.     

Nutrients-mediated shift in temporal expression of phytochrome controlled β-amylase synthesis in mustard (Sinapis alba L.) cotyledons

Abstract. In cotyledons of mustard ( Sinapis alba L.) seedlings grown with distilled water (DW) phytochrome controlled increase in β-amylase (E.C. 3.2.1.2) level takes place at about 42 h after sowing (starting point), while the photoresponse escapes from photoreversibility at 30 h after sowing. The temporal onset of starting point is presumed to be determined by innate process of developmental homeostasis, which is not amenable to influence of environmental factors such as light and nutrients. However, the temporal appearance of onset of phytochrome controlled increase in β-amylase level (starting point) in seedlings grown with Hoagland's nutrient solution (HS) is delayed by 9 h as compared to DW-grown seedlings. Concomitantly, the temporal appearance of the loss of photoreversibility of phytochrome mediated increase in β-amylase level (coupling point) is also delayed by 9 h in HS-grown seedlings. HS does not influence the primary action of phytochrome, the lifetime of components involved in signal chain of above photoresponse and the turnover of β-amylase enzyme. These results indicate that HS-induced temporal shift in onset of starting point of above photoresponse is caused by interaction of nutrients with the process of developmental homeostasis.     

On the Structure of the Seeds of Williamsonia Collected from the Middle Jurassic Rocks of Amarjola in the Rajmahal Hills, India

Seeds of Williamsonia collected from Amarjola in the RajmahalHills, Bihar, are described. Mature seeds are found in ripe,naked, bractless fructifications. Seeds are oblong or ovate,stalked, dicotyledonous, partially endospermic, and have longmicropyles. The seed coat is differentiated into an outer coveringof tubular cells, middle parenchymatous true integument, andan inner vascularized layer which forms after fertilizationand as a result of modification of the peripheral portion ofnucellus.     

Autoradiographic Studies of Uridine-5-H3 Uptake in Entamoeba histolytica in the CLG Medium1

SYNOPSIS. Using uridine-5-H³, “long-term” labeling experiments over a 72 hr growth cycle were done with E. histolytica strain K9 grown in CLG medium with penicillin-inhibited Bacteroides. Autoradiographic analysis revealed that tritium occurs primarily in cytoplasm and rarely the nucleus of amebae. The most extensive cytoplasmic activity was observed during the initial 0–24 hr growth period of amebae as compared to later labeling periods. RNase or RNase followed by DNase extracted a large amount but not all label from amebae. These nucleases were least effective during the initial 24 hr period of growth. Thus it appears that tritium from uridine-5-H³ is not highly specific for RNA in amebae. However, the possibility that such label is associated with RNase-resistant RNA cannot be ruled out. More recent cytochemical studies do indicate the presence of RNase-resistant RNA in the cytoplasm of amebae. The activity found in penicillin-inhibited Bacteroides after uridine-5-H³ labeling and their reaction to the various digestive procedures was similar to amebae at corresponding labeling periods. Therefore at least some of the RNase-resistant material present in the cytoplasm of amebae may be derived from the ingested bacteria; this has been further found by appropriate experiments in which amebae were fed prelabeled bacteria. Nuclear activity when observed (always after 24 hrs growth) was associated either with the periphery of the nucleus and/or the endosome. It was not seen in the nuclear stroma. Some of this activity is RNase-resistant, perhaps representing double or multi-stranded RNA. It therefore appears that RNA is not distributed in the nuclear stroma in “long-term” labeling experiments.     

Egg-float ridge number in Anopheles stephensi: ecological variation and genetic analysis

Eight Indian laboratory stocks of Anopheles stephensi Liston could be grouped into three categories with, respectively, 14-22, 12-17 and 9-15 ridges on the egg-floats. The mode number of ridges among the eggs laid by individual females in these stocks was 16-19, 13-16 and 10-14, respectively. The category with the highest egg-float ridge number corresponded with the type-form and the lowest with var. mysorensis Sweet and Rao; the new egg-float category with ridge number modes of thirteen to sixteen was designated as 'intermediate'. All three forms, i.e. type-form, intermediate and myosorensis were observed in semi-urban areas while only intermediate and mysorensis were seen in rural areas. Breeding experiments indicated no post-copulatory barriers between the populations. Likelihood analysis of the results of crosses and back crosses indicated that variation in ridge number is controlled by more than one genetic factor. The stocks with different ridge numbers are best considered as 'ecological variants'.     

Uptake, Cellular Distribution, and Metabolism of 14C-picloram by Excised Plant Tissues

Excised soybean (Glycine max (L.) Merr.) hypocotyls, barley (Hordeum vulgare L.) coleoptiles, barley leaf sections, and Canada thistle (Cirsium arvense (L.) Scop.) leaf discs continuously absorbed ¹⁴C-picloram from a buffered solution over a 24 h period. After an 8 h uptake period excised sections released up to 30 % of the absorbed picloram into ‘clean’ buffer solution in a 4 h period. Leaf sections released less than did the other tissues. Uptake of ¹⁴C-picloram by soybean hypocotyl and barley coleoptile sections increased with an increase in temperature from 5 to 35°C. Uptake was promoted by added ATP and sucrose but inhibited by actinomycin D, cycloheximide, and DNP. After differential centrifugation of aqueous extracts of ¹⁴C-picloram-treated excised tissues more than 95 % of the radioactivity was in the soluble fraction. In excised barley and Canada thistle leaf tissues, 3 days after treatment, part of the ¹⁴C-picloram was conjugated with plant constituents, largely with sugar(s). After acid hydrolysis of ethanol extracts of such tissues only unaltered picloram was detected. In barley coleoptile and soybean hypocotyl sections no conjugation products of ¹⁴C-picloram were detected.     

Pollen Diffusates of Crotalaria retusa and their Role in pH Regulation

Details of the release of proteins and amino acids from culturedpollen grains and the role of the leached metabolites in pollengermination, pollen tube growth and regulation of pH of theculture medium in Crotalaria retusa have been investigated.In unbuffered media, satisfactory pollen germination and tubegrowth occurred over a wide range of pH values 4.0–9.0.This was related to the ability of pollen diffusates to shiftthe pH to 6.25 in all these media. Similar pollen germinationand pH shift was observed when the pollen was eluted twice beforeculturing. When the pH shift was reduced by using buffered media,optimal germination and tube growth occurred only at pH 6.0.Pollen diffusates had a strong buffering capacity. Proteinsand amino acids released from pollen do not seem to have a directrole in pH regulation. The components involved in pH regulationmay originate from the pollen wall as well as from the cytoplasm. Crotalaria retusa L, pH regulation, pollen diffusates, pollen germination