Effects of Temperature Acclimation Pretreatment on the Ultrastructure of Mesophyll Cells in Young Grape Plants (Vitis vinifera L. cv. Jingxiu) Under Cross-Temperature Stresses

Abstract

Leaves from annual young grape plants (Vitis vinifera L. cv. Jingxiu) were used as experimental materials. The ultrastructural characteristics of mesophyll cells in chilling-treated plants after heat acclimation (HA) and in heat-treated plants after cold acclimation (CA) were observed and compared using transmission electron microscopy. The results showed that slight injury appeared in the ultrastructure of mesophyll cells after either HA (38 °C for 10 h) or CA (8 °C for 2.5 d), but the tolerance to subsequent extreme temperature stress was remarkably improved by HA or CA pretreatment. The increases in membrane permeability and malondialdehyde concentration under chilling (0 °C) or heat (45 °C) stress were markedly inhibited by HA or CA pretreatment. The mesophyll cells of plants not pretreated with HA were markedly damaged following chilling stress. The chloroplasts appeared irregular in shape, the arrangement of the stroma lamellae was disordered, and no starch granules were present. The cristae of the mitochondria were disrupted and became empty. The nucleus became irregular in shape and the nuclear membrane was digested. In contrast, the mesophyll cells of HA-pretreated plants maintained an intact ultrastructure under chilling stress. The mesophyll cells of control plants were also severely damaged under heat stress. The chloroplast became round in shape, the stroma lamellae became swollen, and the contents of vacuoles formed clumps. In the case of mitochondria of control plants subjected to heat stress, the outer envelope was digested and the cristae were disrupted and became many small vesicles. Compared with cellular organelles in control plants, those in CA plant cells always maintained an integrated state during whole heat stress, except for the chloroplasts, which became round in shape after 10 h heat stress. From these data, we suggest that the stability of mesophyll cells under chilling stress can be increased by HA pretreatment. Similarly, CA pretreatment can protect chloroplasts, mitochondria, and the nucleus against subsequent heat stress; thus, the thermoresistance of grape seedlings was improved. The results obtained in the present study are the first, to our knowledge, to offered cytological evidence of cross-adaptation to temperature stresses in grape plants.

Growth of Indian mustard (Brassica juncea L.) in response to salicylic acid under high-temperature stress

“…Studies have revealed that specific effects of high temperature on the plant photosynthetic membrane results in the loss of grana stacking or its swelling. In response to heat stress, chloroplasts in the mesophyll cells of grape plants become round in shape, the stroma lamellae become swollen, and the contents of the vacuole form clumps, whilst the cristae were disrupted and mitochondria became empty (Zhang et al, 2005). Such changes result in the formation of antenna-depleted photosystem-II (PS-II) and hence reduced photosynthetic and respiratory activities (Zhang et al, 2005).…”

The plasma membrane H+-ATPase is related to the development of salicylic acid-induced thermotolerance in pea leaves

“…Membrane fluidity, which is defined as the motion of phospholipid molecules within the lipid bilayer, is influenced by factors such as the interactions of proteins and lipids and ion environments (Huang and Yang 1996). Activation of lipid peroxidation is one of the earliest and nonspecific plasma responses brought by any stress agent, including heat shock (Coote et al 1994;Zhang et al 2005;Liu et al 2006a, b). Interestingly, the MDA assay response obviously decreased in the SA pre-treated leaves, which implies that SA plays an active part in protecting the membrane under heat stress (Fig.…”

“…Recently, our studies showed that the PM-located phosphatidylinositol-4, 5-bisphosphate (PIP 2 )-specific phospholipase C (PLC) was involved in the SA-mediated signal pathway that leads to the acquisition of heat acclimation-induced thermotolerance and functioned downstream of free SA in cell response to heat acclimation treatment (Liu et al 2006a, b), and the changes in PM H ? -ATPase activities and amounts during the cross adaptation to temperature stresses were also detected using electron microscopic cytochemical assay (Zhang et al 2005). And in pea leaves, the enhanced lipid peroxidation could be one of the causes for the H ?…”

Transcriptional profiling in pearl millet (Pennisetum glaucum L.R. Br.) for identification of differentially expressed drought responsive genes

“…SSH has successfully been used to identify genes responsive to various biotic and abiotic stresses in various plant species such as Saccharum (Watt 2003); Festuca (Zhang et al 2005); Pennisetum (Mishra et al 2007); Agrostis (Xu et al 2009); Triticum (Chauhan et al 2011). Thus in the current study we focus on identifying, validating and establishing the putative functions of the major differentially expressed genes in P. glaucum during drought stress response using SSH, real-time quantitative qRT-PCR and homology searches.…”