Ecology of endangered Prunus korshinskyi Hand.-Mazz. in Jabal Al-Lauz, Saudi Arabia: Plant associations, size structure, and nutritional screening.

The wild Prunus korshinskyi has a restricted distribution in small scattered areas of Jabal Al-Lauz (2580 m above sea level), a mountain in northwestern Saudi Arabia. Major objective of current study is to provide information about P. korshinskyi by analyzing its ecology in terms of floristic diversity, plant associations, environmental features, and its size structure and nutritional value. For this purpose, 12 stands of 20 m2 were selected along the Jabal Al-Lauz mountain ridge. Three plant associations and their environmental variables were identified and characterized after application of a two-way indicator species analysis (TWINSPAN), detrended correspondence analysis (DCA). And canonical correspondence analysis (CCA) as follows: VGI: P. korshinskyi-Astracantha echinus, VGII: Artemisia siberi-P. korshinskyi, and VGIII: Retama raetam-Artemisia sieberi. The edaphic factor affecting the distribution of the associations were pH, potassium and manganese content. The size class frequency distribution of P. korshinskyi shows a J-shape in spring and fall for the whole population; there was no regeneration via seed. Nutritional evaluation showed the fruits had a higher content of total carbohydrate, fats, crude protein, phosphorus, and potassium, and lower content of ash, Fe, Ca, Mn, Mg, and Zn than that in stems and leaves. This ecological knowledge gained through this study would be beneficial for managing and conserving of P. korshinskyi in a Jabal Al-Lauz area with its distinct and unique vegetation.

Analysis of the cuticular wax composition and ecophysiological studies in an arid plant - Ziziphus nummularia (Burm.f.) Wight & Arn.

Plants in arid regions are exposed to various abiotic stresses and the presence of the waxy cuticular layer acts as a defensive barrier, which consists mainly of long chain fatty acids, hydrocarbons and other derived compounds. Studies on the chemical composition and properties of cuticles of arid plants are scanty. The present study deals with the analysis of cuticular wax composition and effect of temperature on some ecophysiological parameters of an important arid plant Ziziphus nummularia. A total of 59 different wax compounds were detected from the leaf cuticle by capillary GC-MS. 4-Hydroxycyclohexanone, Heptacosane and 2,7-Dimethyloctane-3,5-dione were the dominant wax compounds in Z. nummularia. The variation of photosynthetic rate varied from 0.70 to 7.70 µmol CO2 m-2s-1 against the studied temperature range of 15-55 °C. The transpiration rate varies from 1.80 to 8.40 mmol H2O m-2s-1 within the temperature range of 15-55 °C. The quantum yield of photosystem II (Fv/Fm) also exhibited much variation due to the variation of temperature. The results clearly shows that Z. nummularia is highly adapted to restrict water loss and can tolerate high temperatures and can be considered as an appropriate species for vegetating the arid areas.

Threatened Prunus arabica in an ancient volcanic protected area of Saudi Arabia: Floristic diversity and plant associations.

Prunus arabica (Oliv.) Meikle is an endangered shrub with a restricted distribution, which inhabits banks of flood flow channels in small sites of ancient volcanic activity dominated by black basaltic boulders within the Harrat Al-Harrah protectorate, Northern Saudi Arabia. It is with limited information about its ecology and hence, the present study is focusing on its phytosociological behavior and ecological features. The multi-methodological approach comprised species description, vegetation sampling and soil composition of 9 study sites at Harrat Al-Harrah protectorate. The application of TWINSPAN, DCA and CCA multivariate analyses led to identify 3 vegetation groups (VGI: Pulicaria undulata-Prunus arabica, VGII: Prunus arabica-Artemisia seiberi, VGIII: Artemisia seiberi-Achillea fragrantissima) associated with the distribution of P. arabica. The environmental variables that affect P. arabica and its main ecological features had been estimated and discussed. The present study concludes that the main reasons for its threatened and endangerment are seemingly due to overgrazing, poor rainfall, drought, shifting and destruction of its suitable habitat area.

Birth anthropometric parameters in high and low altitude areas of Southwest Saudi Arabia.

OBJECTIVES: To study the anthropometric parameters of Southwestern Saudi newborns in Abha (a high altitude area) and Baish (a sea level area of Southwestern Saudi Arabia); to compare these parameters with those of the United States Center for Disease Control 2000 growth charts and to estimate the incidence of low birth weight (LBW) among the study population. METHODS: The study sample included all births from Abha Central Hospital (N=4300), and all births from Baish General Hospital (N=1200), Kingdom of Saudi Arabia during the period from January 2001 to January 2003. Only term births (>37-42 weeks gestation) were included. The anthropometric measurements included birthweight, crown-heel length and head circumference. The head circumference (occipitofrontal) was measured to the nearest 5 mm with an inelastic tape. Babies of LBW were identified. Low birth weight was defined as <2,500 gms at birth. Ponderal index (PI) was calculated using the formula of birthweight (in grams) x 100/length3. RESULTS: Saudi newborns are lighter and shorter than those of National Center for Health Statistics newborns. The same finding was evident for head circumference. Newborns from Abha are lighter (p<0.001) and shorter (p<0.001) than from Baish. However, this difference was not significant for head circumference (p=0.53). Abha newborns showed significantly lower mean weight (2845.4 gms versus 2951.8 gms, t=58, p<0.001), and lower mean length (48.1 cm versus 48.5 cm, t=4.65, p<0.001). Low birth weight was prevalent among 24.6% of all newborns. This figure was significantly higher among newborns from Abha (25.7%) than its counterpart in Baish (20.7%), p<0.001. A strong positive correlation between the PI and birthweight (p<0.0001, R2=0.52), after adjusting for the place of birth was evident. CONCLUSION: Neonates of Southwestern Saudi Arabia are significantly lighter and shorter than those of the reference population, as well as neonates in other areas of the Kingdom, with prevalent LBW especially in high altitude area, possibly due to intra-uterine growth retardation of secondary type. Ponderal index is significantly associated with birth weight even after adjusting for gender and place of birth. This might encourage the use of PI as an alternative to birth weight especially when gestational age is not available.