Drought Stress Impairs Grain Yield and Quality of Rice Genotypes by Impaired Photosynthetic Attributes and K Nutrition

正Drought is one of the most prevalent abiotic stresses that adversely affect rice productivity(Petrozza et al, 2014). Rice is very sensitive to drought stress and drought can cause 50% reduction in rice production globally(Yang et al, 2008). To meet the food needs for global population, 63% more agricultural production will be required by the year 2050 than     

Zur Morphologie und Entwicklung von Bracon instabilis Marsh. (Hym., Braconidae), eines Parasiten der Kartoffelmotte,Phthorimaea operculella Zell. (Lep., Gelechiidae) in Ägypten

Bracon instabilis Marshal is an ectoparasite attacking the larvae ofP. operculella in Egypt. According to available literatures, this is the first study onB. instabilis. The laboratory rearing of this parasite was undertaken on the third and fourth larval instars ofP. operculella and the method was mentioned in details. Certain aspects of the morphology of the immature and adult stages were given. The durations of the immature stages of the parasite were estimated at 15 and 25°C and 60±5% R.H. The total durations of the immature stages (from egg to adult) were 39.62 and 11.19 days at 15 and 25°C, respectively.     

Determining suitability of thermal development models to estimate temperature parameters for embryonic development of <Emphasis Type="Italic">Sitona lepidus</Emphasis> Gyll. (Coleoptera: Curculionidae)

The clover root weevil, Sitona lepidus Gyll. is a pest of clovers (Trifolium spp.), particularly white clover (T. repens). Larva feeding severely impairs the capacity of white clover to fix atmospheric nitrogen, by attacking the nitrogen-fixing root nodules. Development of the egg stage was studied at six different constant temperatures ranging from 9 to 30°C to improve the basis for phenological forecasts. Development occurred over the entire range of temperatures, although hatching percentage at 30°C was only 24.4% compared to 90.1% at 28.5°C. Developmental time decreased with increase in temperature from 9 to 28.5°C but increased markedly at 30°C. At 28.5°C, the embryo development period was the shortest (10.35 days); whereas at 9°C, this parameter was the longest (55.08 days). Using linear regression, the lower threshold temperature was calculated 4.38°C and the thermal constant was 236.45 degree-days. The relationship between constant temperature and developmental rate was evaluated using nine models. The suitability of the models was evaluated based on eight indicators (R ², RSS, R _adj², AIC, BIC, AICC, W _j , and Z _i ). Of the nonlinear models, the Logan-6, Sharpe and DeMichele, and Lactin models were the most accurate at calculating t _opt of 27, 27.50, and 28°C, respectively. The results suggest that of the three models (Lactin, Briere, and Hilbert and Logan), that estimated critical temperatures, (t _min, t _opt, and t _max), Lactin gave the most suitable fit of data. This response of S. lepidus to temperature can be used for developing phonological models to predict the timing of egg hatch which are important for management programs targeting the weevil.     

Determining milk isolated and conjugated trans-unsaturated fatty acids using fourier transform Raman spectroscopy

The feasibility of Raman spectroscopy in combination with partial least-squares (PLS) regression for the determination of individual or grouped trans-monounsaturated fatty acids (trans-MUFA) and conjugated linoleic acids (CLA) in milk fat is demonstrated using spectra obtained at two temperature conditions: room temperature and after freezing at -80 °C. The PLS results displayed capability for direct semiroutine quantification of several individual CLA (cis-9,trans-11 and trans-10,cis-12 C18:2) and trans-MUFA (trans-4-15 C18:1) in minor concentrations (below 1.0 g/100 g of milk fat). Calibration models were based on reference data cross-correlation or determined by specific scattering signals in the Raman spectra. Distinct bands for trans-MUFA (1674 cm(-1)) and CLA (1653 cm(-1)) from the trans isolated and cis,trans conjugated C ═ C bonds were identified, as well as original evidence for the temperature effect (new bands, peak shifts, and higher intensities) on the Raman spectra of fatty acid methyl ester and triacylglyceride standards, are supplied.     

Chemical Manipulation of Reproductive Efficiency of Chickpea (Cicer arietinnum L.) by Triadimefon in Relation to Changes in Ethylene

Reproductive efficiency was successfully manipulated by the application of different concentrations of triadimefon at pre‐flowering, flowering and post‐flowering stages in chickpea (Cicer arietinum L.). Triadimefon improved the parameters determining reproductive efficiency. Yield was significantly improved due to reductions in flower and pod abscission by the application of triadimefon, which also lowered the ethylene levels in leaves, flowers and pods and delayed senescence. These findings suggest a relationship between ethylene level and reproductive efficiency in chickpea. Further, they indicate that triadimefon can be used for chemical manipulation of the reproductive efficiency of chickpea under field conditions.     

托木尔峰自然保护区地衣的补充研究

我们根据多年的研究并结合前人的工作进一步地整理了分布在新疆托木尔峰自然保护区的地衣种类。分析该地区的地衣种有１２０个，分别隶性于４９属，其中有１１个变种和４个变型。调查中我们还发现该地区地衣随着海拔高度的升高而有所不同，北坡和南坡也有明显的差异。     

Potassium distribution in root and non‐root zones of two cotton genotypes and its accumulation in their organs as affected by drought and potassium stress conditions

A rhizobox experiment was conducted to compare the differences of soil potassium (K) distribution and absorption between two cotton (Gossypium hirsutum L.) genotypes under drought and K‐deficit conditions. Treatments included two levels of water (drought and optimum soil moisture: 25% and 35% volumetric water content) and K fertilizer rates (0 and 0.48 g potash kg^?1 soil) applied to two cotton genotypes (namely HEG and LEG). Both the genotypes showed significant differences in total K accumulation without exogenous K addition. After absorption, soil content of the readily available potassium (RAK) decreased rapidly. This promoted the conversion of the mineral K into slowly available potassium (SAK). Drought significantly decreased the cotton growth and K use efficiency, and thereby reduced the effect of K fertilizer. Consequantly, the contents of RAK and SAK were greatly increased. However, K bioavailability was decreased under water stress conditions. Differences in root parameters and soil microorganisms between two cotton genotypes were significantly increased and had marked relations with available soil K contents. This study provides important information for understanding the mechanism of K use efficiency, especially under water and K stress.     

Influence of different microalgal diets on gonadal development of the carpet shell clam <Emphasis Type="Italic">Ruditapes decussatus</Emphasis> broodstock

Studies considering broodstock conditioning of Ruditapes decussatus mostly used flagellates and diatoms for feeding, mainly Isochrysis galbana and Chaetoceros calcitrans, respectively. The present study evaluated the effect of different microalgal diets on gonadic maturation of R. decussatus including three microalgae species (C. calcitrans, Tetraselmis suecica, and Nannochloropsis oculata) which were used to prepare six diets: three monospecific and three bispecific mixed diets at a proportion of 1:1. Clams were daily fed at a ratio of 1% dry weight of algae/live weight of clam and unfed treatment was used as control. Results showed that clams fed C. calcitrans alone or mixed with T. suecica attained earlier full maturity with the highest response to spawning induction (after 34 conditioning days) and largest proportion in the partial spawning phase for both, followed by T. suecica alone after 48 days. In contrast, N. oculata alone or mixed diets demonstrated poor performance for gonadal maturation. Unfed treatment did not show any sign of maturation. The results indicated that T. suecica has high conditioning potential like C. calcitrans and their mixture gave the highest benefit. Therefore, T. suecica can be recommended for R. decussatus broodstock conditioning.     

Can camels disperse seeds of the invasive tree Prosopis juliflora?

Endozoochory has been recognised as the most important dispersal mechanism in invasive Prosopis species, because their sugary, tasty pods attract animals and because some of their seeds remain intact after passing through some animals' digestive systems. In this study, we evaluated the role of the camel (Camelus dromedarius) as a potential disperser of the seeds of invasive tree Prosopis juliflora. Four camels of similar weight (ca. 400 kg) and age (ca. 2 years) were each fed with 70 fruits (1000 seeds approximately) of P. juliflora, which were retrieved from the camels' dung at 24‐h intervals for 4 days. The seeds retrieved were tested for germination and viability, along with seeds not eaten by the camels, with and without pericarp. Less than 3% of the seeds eaten were retrieved from the camels' dung. Most of the seeds (74%) were retrieved between 24 and 72 h after ingestion. The passage through the camel gut significantly accelerated and increased seed germination of P. juliflora in comparison with uneaten seeds covered with pericarp (48–75% and 15% respectively). While gut passage liberated P. juliflora seeds from the pericarp, increasing and accelerating their germination, the viability of seeds which had not germinated after germination trials were decreased (ca. ~20%) relative to uneaten seeds that had also not germinated. Our results show that, despite the low recorded seed recovery, camels can potentially disperse seeds of P. juliflora, which is in line with field observation showing P. juliflora expansion along the camels' routes in Gebel Elba National Park, south‐east Egypt.