دور المركبات الثانوية (Secondary products) لنبات الآس Myrtus communis L في تثبيط نشاط إنزيم اليوريز في التربة Role of secondary products of myrtus (Myrtus communis L) as urease inhibitors in soil

Abstract

A study was conducted to evaluate the effect of secondary products (essential oil resins saponins alkaloids and phenolics) extracted from myrtus (Myrtus communis L) leaves on urease inhibition in soil Soil samples were collected from Al–Zubair region (Basrah province south of Iraq) Soil classified as Entisol ; Typic quartizpsamment Soil samples were treated with urea at levels of 1000 mg N \ Kg soil and solutions of each secondary product were added at rates of 05 50 and 100 % w w of urea and incubated at 30 C ± 2 for 40 days Samples from incubated soil were withdrown after 5 10 20 and 40 days and urease activity was assayed then inhibition percentage was calculated Results of the study showed that Treated soils with different concentrations of resins saponins or alkaloids did not significantly affect urease activity in soil at all incubation periods However phenolics or essential oils extracts added to soil significantly inhibited urease activity in soil The inhibition percentage was 51 and 27 % for phenolics and essential oils respectively Results also revealed that significant inhibition effects of phenolics extract continued for 40 days while those of essential oils lasted for 10 days only This study suggests that the inhibition effect of myrtus leaves on urease activity in soil attributed mainly to phenolics compound of plant leaves

أجريت هذه الدراسة لبيان تأثير المركبات الثانوية (Secondary products) والتي تشمل الزيوت الطيارة (Essential oils) والراتنجات (Resins) والصابونيات (Saponines) والقلوانات (Alkaloids) والفينولات (Phenolics) المستخلصة من نبات الآس Myrtus Communis L في تثبيط نشاط إنزيم اليوريز في تربة أخذت من منطقة الزبير محافظة البصرة العراق والمصنفة تحت رتبة Entisol وضمن مجموعة الترب العظمى Typic quartzipsamment تم اختبار كفاءة هذه المركبات من خلال حضنها كل على حدة بثلاثة تراكيز هي 05 و50 و100 % من وزن اليوريا (المضافة بمستوى 1000 ملجم N كجم تربة) مع 5 جم تربة لمدة 40 يوما على درجة حرارة 30 م ± 2، ثم أخذت عينات لكل معاملة بعد 5 و10 و20 و40 يوما من الحضن وقدر فيها نشاط إنزيم اليوريز ومن ثم حسبت النسبة المئوية لتثبيط نشاط الإنزيم