Limitation of the Cavitron technique by conifer pit aspiration.
نویسندگان
چکیده
The Cavitron technique facilitates time and material saving for vulnerability analysis. The use of rotors with small diameters leads to high water pressure gradients (DeltaP) across samples, which may cause pit aspiration in conifers. In this study, the effect of pit aspiration on Cavitron measurements was analysed and a modified 'conifer method' was tested which avoids critical (i.e. pit aspiration inducing) DeltaP. Four conifer species were used (Juniperus communis, Picea abies, Pinus sylvestris, and Larix decidua) for vulnerability analysis based on the standard Cavitron technique and the conifer method. In addition, DeltaP thresholds for pit aspiration were determined and water extraction curves were constructed. Vulnerability curves obtained with the standard method showed generally a less negative P for the induction of embolism than curves of the conifer method. Differences were species-specific with the smallest effects in Juniperus. Larix showed the most pronounced shifts in P(50) (pressure at 50% loss of conductivity) between the standard (-1.5 MPa) and the conifer (-3.5 MPa) methods. Pit aspiration occurred at the lowest DeltaP in Larix and at the highest in Juniperus. Accordingly, at a spinning velocity inducing P(50), DeltaP caused only a 4% loss of conductivity induced by pit aspiration in Juniperus, but about 60% in Larix. Water extraction curves were similar to vulnerability curves indicating that spinning itself did not affect pits. Conifer pit aspiration can have major influences on Cavitron measurements and lead to an overestimation of vulnerability thresholds when a small rotor is used. Thus, the conifer method presented here enables correct vulnerability analysis by avoiding artificial conductivity losses.
منابع مشابه
Embolism resistance of three boreal conifer species varies with pit structure.
While tracheid size of conifers is often a good proxy of water transport efficiency, correlations between conifer wood structure and transport safety remain poorly understood. It is hypothesized that at least some of the variation in bordered pit and tracheid structure is associated with both transport efficiency and embolism resistance. Stem and root samples from three boreal Pinaceae species ...
متن کاملEffect of Distraction Technique and Hypnosis in Pain of Bone Marrow Aspiration in Children: a Narrative Review
BackgroundThe present review study provides specific evidence to assess the impact of distraction techniques and hypnosis on the pain of bone marrow aspiration in children.Materials and MethodsThis review study aimed to determine the effects of distraction techniques and hypnosis on the controlling pain of bone marrow aspiration in children. Internal databases (SID, Magiran, IranMedex and Irand...
متن کاملAnesthetic Efficacy of Inferior Alveolar Nerve Block: Conventional versus Akinosi Technique
Objective: Anesthetic techniques like the Akinosi technique were introduced to surmount the problems of the conventional inferior alveolar nerve block (IANB) technique. This study aimed to compare the local anesthetic efficacy of IANB via the conventional and Akinosi techniques in patients presenting to the Maxillofacial Surgery Department of School of Dentistry, Shahid Beheshti University. Me...
متن کاملPlasmodesmatal pores in the torus of bordered pit membranes affect cavitation resistance of conifer xylem.
The pit membrane in bordered pits of conifer tracheids is characterized by a porous margo and central thickening (torus), which is traditionally considered to function as an impermeable safety valve against air-seeding. However, electron microscopy based on 33 conifer species, including five families and 19 genera, reveals that pores occur in the torus of 13 of the species studied. The pores ha...
متن کاملThe Treatment of Brain Abscess of Children in Loghman-E-Hakim Medical Center
SUMMARY In this study the result of the treatment of 41 patients from one month to 15 years old during 1984 to 1994 in neurosurgical department of Loghman -eHakim Medical Center is evaluated. All patients have been managed into 2 groups; The first, including of 36 patients that have been operated by aspiration technique and the second group including of 7 patients were operated by resection S...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of experimental botany
دوره 61 12 شماره
صفحات -
تاریخ انتشار 2010