Effects of metamitron on fruit set and photosynthetic biological characteristics of apples.

With dwarfing interstock Fuji apples as the test materials and water treatment as the control (CK), we examined the fruit thinning effect and its influences on leaves' photosynthesis by spraying 200, 300, and 400 mg·L-1 metamitron during the young fruit period to solve artificial fruit thinning problems (time-consuming, much labor, and low efficiency). The results showed that metamitron application could significantly reduce the inflorescence and flowers' fruit-setting rate by 16.5%-22.8% and 50.9%-53.9%, respectively. The treatment of 300 mg·L-1 metamitron had the strongest fruit thinning effect, with a single fruit rate of 46.6% and a double fruit rate of 18.3%. As a photosynthesis inhibitor, metamitron application reduced the chlorophyll content of leaves and strongly affected photosynthesis. The inhibitory effect on chlorophyll content disappeared after 15 days of the treatment, while that on the net photosynthetic rate disappeared gradually after 11 days of the treatment. The application of metamitron significantly reduced the maximum quantum yield of PSⅡ reaction center (Fv/Fm), actual photochemical efficiency (ΦPSⅡ), photochemical quenching coefficient (qP) and non-photochemical quenching coefficient (NPQ), with such inhibitory effect having been lasted for 15 days. OJIP analysis showed that metamitron caused damage to the apple leaves' oxygen-evolving complex, especially limiting the transfer of electrons in the PSⅡ reaction center from QA to QB. Metamitron treatment increased Wk, and significantly decreased ψo, RC/CSm, and PIabs. Besides, 300 mg·L-1 metamitron had the most significant effect. Our results showed that metamitron destroyed the structure of the PSⅡ reaction center of apple leaves and hindered the transfer of electrons from the donor to the receptor of PSⅡ. Consequently, the photosynthetic rate was affected, and the young fruits fell off due to the lack of accumulation of photosynthetic products.

[Analysis of the outcomes of squamous cell carcinoma of maxillary sinus with 3 different comprehensive treatments].

PURPOSE: To study the medium or long-term survival rates of different methods used in the treatment of advanced squamous cell carcinoma of the maxillary sinus (SCMS). METHODS: Patients were treated by one of the following methods: 231 patients were treated with induction chemotherapy, followed by radical resection and radiotherapy (CSR); 128 patients were treated with preoperative irradiation (RS), and 87 patients underwent adjuvant radiotherapy (RSR). A total of 446 cases of SCMS from June 1985 to December 2008 were managed with unscheduled application of the above 3 kinds of treatment options. The dose of 231 patients with CSR and 128 patients with RS was 60-70 Gy/30-35 times/5-7 week and 40-50 gy/20-25 times/4-5 week, respectively. Dose in RSR accounted for half of that in CSR. The number of cases undergoing total resection of maxilla, subtotal resection of maxilla and extended excision of maxilla were 299, 111 and 36, respectively (13 cases had orbital exenteration). The number of patients with therapeutic radical neck dissection, functional neck dissection and supraomohyoid neck dissection were 49, 73 and 56, respectively. The data was analyzed with SPSS16.0 software package. RESULTS: Five-year survival rate in 446 cases was 45.96% (205/446), and 220 patients died of tumors, among which 84.09% (185/220) of death were due to local recurrences. The 5-year survival rate of CSR, RS, and RSR were 45.88% (106/23), 46.09% (59/128) and 45.97% (40/87), respectively; Totally 83.33% of CSR, 85.71% of RS and 83.72% of RSR died of local recurrences. There was no significant difference in the survival rates among CSR, RS and RSR. CONCLUSIONS: Unscheduled comprehensive treatment have a higher 5-year survival rate in this advanced SCMS. Elective neck irradiation and neck dissection are necessary for medium or advanced squamous cell carcinoma of maxillary sinus.

[Grade IV myelosuppression after induction chemotherapy of TPF on oral cancer: clinical analysis of 29 cases].

PURPOSE: To observe and evaluate the clinical features and treatment strategies of IV myelosuppression after induction chemotherapy of oral mucosa squamous cell carcinoma under conventional dosage. METHODS: Twenty-nine patients of oral mucosa squamous cell carcinoma pathologically diagnosed between 2006 and 2012 were enrolled into this study. The patients received induction chemotherapy with docetaxel-cisplatin-5-fluorouracil (TPF) and suffered from grade IV myelosuppression. Regulations and treatment strategies of the bone marrow myelosuppression were analyzed, retrospectively. RESULTS: Twenty-nine cases had bone marrow suppression 9-14 days after induction chemotherapy, and the median time was 10 days, with a "U"-shaped fluctuation pattern. There were 26 cases with colony-stimulating factor(CSF) therapy completing treatment according to the schedule and 2 cases were required to radiotherapy because of unsatisfied effect of CSF therapy. One case died and the death rate after chemotherapy was 0.68% in this group. CONCLUSIONS: The incidence of grade IV myelosuppression is normal and fatal. This study shows the starting time of the "U"-shaped fluctuation and the necessaries of adding CSF therapy at the same time. The emergency treatment of myelosuppression should be used including single disinfected ward mouthwash and therapy of CSF drug.

[Responses of primary photochemical reactions in apple fruit peel to the changes of incident PFD and air temperature in sunny days].

Taking Malus domestica Borkh as test object, this paper studied the primary photochemical reactions and xanthophyll cycle in its fruit peel in response to the diurnal changes of incident photon flux density (PFD) and air temperature in sunny days. With the increase of PFD and air temperature in a daily cycle, a severe photo-inhibition of the primary photochemical reactions in M. domestica fruit peel occurred from 12:00 to 14:00. The relative variable fluorescence at 300 micros of chlorophyll a fluorescence transient (Wk) did not change significantly through the day, which indicated that the activity of oxygen evolving complex (OEC) was not damaged by strong light and high temperature. However, the efficiency that a trapped exciton moved an electron into the electron transport chain beyond QA(-) (Psio) was reduced from 12:00 to 14:00, indicating that the acceptor side of PS II in apple fruit peel was damaged. Strong light decreased the density of PS II reaction centers per excited cross-section (RC/CS), which induced the increase of the energy absorption per active reaction center (ABS/RC). However, the excited energy was not able to be efficiently used via photochemical reaction (TRo/RC), resulting in an increase in non-photochemical energy dissipation per active reaction center (DIo/RC). Along with the appearance of photo-inhibition, the de-epoxidation level of xanthophyll pigment pool (PRI) increased markedly, showing that the xanthophyll cycle in fruit peel was enhanced by strong light to dissipate excess excitation energy to prevent photosynthetic apparatus from further damage. Both strong light and high temperature enhanced the photo-inhibition in apple fruit peel, and the effect of strong light was significantly more prominent than that of high temperature during a day.