Study On The Physiological Effects And Mechanism Of Cut Rose During Vase

Using sodium nitroprusside (SNP) as a nitric oxide (NO) donor, the effects of NO treatment on vase life, wilt rate, fresh mass increase, MDA content, relative membrane permeability, anthocyanin content, PAL activity, endogenous hormone content, and the corresponding enzymatic activity of respiration and ethylene synthesis of cut rose'Kardinal'were studied.Using sodium nitroprusside (SNP) as a nitric oxide (NO) donor, 2-phenyl-4,4,5,5 -tetramethylimidazoline-1-oxyl-3-oxide (PTIO) as a NO scavenger, Nω-nitro-L-arginine (LNNA) as a NOS inhibitor, Ca²⁺, thylene-glycol-bis(β-aminoethyether) N,N,N,N-tetracetic acid (EGTA) as a Ca²⁺ chelator, trifluoperazine (TFP) as a calmodulin (CaM) antagonist, The mechanism of Ca²⁺ in regulation of ethylene biosynthesis modulated by nitric oxide, and the role of Ca²⁺ in NO signal transduction were discussed. The results as follows:1. The results showed that NO resulting from 0.1mmol·L-1 SNP aqueous solution for 3 hours markedly decreased wilt rate, increased fresh mass, prolonged vase life of cut rose.2. Exogenous NO obviously slowed down the increase of MDA content and the relative membrance permeability in petals of cut rose during vase. At the same time, nitric oxide also slowed down the increase of anthocyanin content and PAL activity in petals of cut rose, and deferred the accumulation of the flower color begotten by the senescence of cut rose.3. COX together with AO and PPO participated in the respiration of cut rose. COX and AO exert to the respiration in petals of cut rose during the former vase (4 day before); but PPO played an important role in the respiration of cut rose during the latter vase (2 days after). Exogenous NO inhibited COX, AO and PPO activities, decreased the respiration rate, delayed the respiration peak of cut rose during vase.4. Treatment with Exogenous NO inhibited the increase of LOX, ACS, and ACO activities, decreased ACC accumulation. The contrary results were obtained in PTIO treated flowers. These results above indicated that NO on modulation to senescence were possibly be related to the ethylene biosynthesis in petals of cut rose.5. Multiplicate plant endogenous hormones (including ethylene, ABA, IAA, GA, ZR) were concerned with the regulation on the senescence of cut rose. Ethylene and ABA accelerated the senescence of cut rose. The increase of ethylene and ABA contents were more important than the others, but it were also necessary that IAA and ZR contents double-quick decreased in petals of cut rose for the senescence of cut rose; In this time, GA content was just a small change. Exogenous NO significantly inhibited the increase of endogenous ethylene and ABA contents, delayed endogenous the reduction of IAA content in petals of cut rose, maintained relative lower levels of ZR and GA in petals of cut rose during vase.6. The NOS-like activity was detected in petals of cut rose, and NOS catalyzed the production of NO. In the former phase of during vase, with gradual decrease of NOS activity, Endogenous NO content reduced, which induced the increase of the endogenous ethylene content in petal during vase, so cut rose began to senesce. With the development of the senescence of the tissue, endogenous NO content quickly increased again.7. Exogenous Ca²⁺ treatment improved NOS activity during the former vase, delayed the decrease of NOS activity induced by cut rose senescence, maintained relative higher NO content in petals. Furthermore,Ca²⁺ treatment also postponed the increase of NOS activity during the latter vase. Consequently, it inhibited destruction of high concentration NO to which conversion of L-arginine catalyzed by NOS. Further study showed that EGTA and TFP treatment stimulated ACS and ACO activity, accelerated the increase of ACC content, advanced the ethylene biosynthesis in petals during vase; At same times, PTIO (NO scavenger) also inhibited the decrease of ACS, ACO activities and ACC content which induced by Ca²⁺ treatment. Therefore, this also proved that Ca²⁺ and CaM participated in regulation of endogenous ethylene biosynthesis and signal transduction of ethylene during cut rose senescence.