Structural and functional damage caused by boron deficiency in sunflower leaves

Title:

Structural and functional damage caused by boron deficiency in sunflower leaves

Creator:

El-Shintinawy, F.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:5365a385-f0f1-49d9-be90-eaef0e2f9ea8
uuid:5365a385-f0f1-49d9-be90-eaef0e2f9ea8
issn:0300-3604
doi:10.1023/A:1007096105491

Subject:

chlorophyll, dry mass of roots and shoots, fluorescence, Hill reaction, lipoxygenase, malondialdehyde, peroxidase, photosystem 2, potassium, and saccharose

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

Boron deficiency induced a dramatic inhibition in sunflower plant growth, shown by a reduction in dry mass of roots and shoots of plants grown for 10 d in nutrient solution supplied with 0.02 µM B. This low B supply facilitated the appearance of brown purple pigmentation on the plant leaves over the entire growth period. Compared to B-sufficient (BS) leaves, leakage from B-deficient (BD) leaves was 20 fold higher for potassium, 38 fold for sucrose, and 6 fold for phenolic compounds. High level of membrane peroxidation was detected by measuring peroxidase activities as well as peroxidative products in BD sunflower plants. Soluble and bound peroxidase activities measured in BD thylakoid membranes were accelerated two fold compared to those detected in BS-membranes. No detectable change in soluble peroxidase activity in roots whereas a 4 fold stimulation in bound peroxidase activity was detected. Thylakoid membranes subjected to low B supply showed enhancement in lipoxygenase activity and malondialdehyde (MDA) content in parallel with 40 and 30 % decrease of linoleic and linolenic acid contents (related to total unsaturated fatty acids). A slower rate of Hill reaction activity (40 %) and a suppressed flow of electron transfer of the whole chain (30 %) were detected in BD thylakoid membranes. This reduction was accompanied with a decline in the activity of photosystem 2 shown by a diminished rate of oxygen evolution (42 %) coupled with a quenching (27.5 %) in chlorophyll a fluorescence emission spectra at 685 nm (F685). Thus B is an important element for membrane maintenance, protection, and function by minimizing or limiting production of free oxygen radicals in thylakoid membranes of sunflower leaves.

Language:

Multiple languages

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Coverage:

565-573

Source:

Photosynthetica | 1999 Volume:36 | Number:4

Harvested from:

CDK

Metadata only:

false