[Application of non-invasive microelectrode ion flux estimation technique in crop stress physiology.] / éžæŸä¼¤ç¦»å­æµæ£€æµ‹æŠ€æœ¯åœ¨ä½œç‰©é€†å¢ƒç ”ç©¶ä¸­çš„åº”ç”¨.

Non-invasive microsensing technique has been widely used in evaluating the adaptive responses of plant cells and tissues to abiotic stresses. One of the representative techniques is the microelectrode ion flux estimation (MIFE), which allows concurrent quantification of net fluxes with high spatial and temporal resolution. More importantly, this technique permits simultaneous recording of ion concentration and mobility with less intervention to the in situ physiological status. With the availability of such advanced technique, the last three decades have seen a significant progress towards the role of ion signaling in a variety of abiotic stresses including salinity, extreme temperature, osmotic stress, hypoxia, and drought. In this review, we gave a brief introduction of the MIFE working principles and focused on its applications in detecting ion responses to various abiotic stresses.

Isolation and Functional Analysis of ZmLTP3, a Homologue to Arabidopsis LTP3.

Plant lipid transfer proteins (LTPs) are encoded by multigene families and play important roles in plant physiology. One full-length cDNA encoding an Arabidopsis LTP3 homologue was isolated from maize by RT-PCR and named as ZmLTP3. RT-PCR analysis indicated that the ZmLTP3 expression is induced by salicylic acid (SA), mannitol and salt. Furthermore, in different tissues the ZmLTP3 displayed different expression patterns, indicating that ZmLTP3 may play multiple roles in stress resistance. Over-expression of ZmLTP3 in wild-type Arabidopsis resulted in the increased salt tolerance. Under salt stress condition, compared to wild-type (WT) plants, transgenic Arabidopsis grew better, had higher seedling fresh (FW), dry weight (DW), seed yields, proline content and lower MDA content and relative electric conductivity level. Our results suggest that maize ZmLTP3 might encode a member of LTPs family and play roles in salt resistance.

[Effects of exogenous silicon on the pollination and fertility characteristics of hybrid rice under heat stress during anthesis].

Taking two medium-maturing indica rice hybrids Jinyou 63 and Shanyou 63 as test materials, this paper studied the effects of applying silicon fertilizer on the flag leaf chlorophyll content, photosynthetic properties, antioxidant enzyme activities, malondialdehyde (MDA) content, pollen vigor, anther acid invertase activity, pollination, and seed-setting of hybrid rice under the heat stress during anthesis. This study was conducted in pots and under growth chamber. Soluble solution of silicon fertilizer applied as Na2SiO3 x 9H2O was sprayed on the growing plants after early jointing stage, with three times successively and at an interval of one week. The pots were then moved into growth chamber to subject to normal temperature vs. high temperature (termed as heat stress) for five days. In treatment normal temperature, the average daily temperature was set at 26.6 degrees C, and the maximum daily temperature was set at 29.4 degres C; in treatment high temperature, the average and the maximum daily temperature were set at 33.2 degrees C and 40.1 degrees C, respectively. As compared with the control, applying silicon increased the flag leaf chlorophyll content significantly, improved the net photosynthetic rate and stomatal conductance, decreased the accumulative inter- cellular CO2 concentration, improved the leaf photosynthesis, reduced the MDA content, and improved the activities of SOD, POD and CAT under heat stress. In addition, applying silicon improved the anther acid invertase activity and the pollen vigor, increased the anther basal dehiscence width, total number of pollination per stigma, germinated number, germination rate of pollen, and percentage of florets with more than 10 germinated pollen grains, decreased the percentage of florets with fewer than 20 germinated pollen grains, and thus, alleviated the fertility loss of Jinyou 63 and Shanyou 63 under heat stress by 13.4% and 14.1%, respectively. It was suggested that spraying exogenous silicon in the early growth period of rice could mitigate the decrease of seed-setting at flowering stage, and improve the heat resistance of hybrid rice.

[High temperature stress on rice anthesis: research progress and prospects].

High temperature-induced rice sterility at anthesis is characterized by its organ-specific, high severity, and low predictability of occurrence. This paper summarized the research advances in rice sterility at anthesis under high temperature, including occurrence period, injury temperature regime, differences in responses among varieties, damage mechanisms, evaluation methods, genetics of tolerance traits, and molecular biology of anther dehiscence and pollen abortion, etc. Based on the relevant researches in Japan as well as the studies in Jianghan Plain, China on the climate conditions under which high temperature-induced damage on middle-season rice hybrids occurred, some key points and main options for the further research were suggested.